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C H A P T E RO U T T I N E
An Overview
of l\utrition
Food Choices
The Nutrients
Nutrientsin Foodsand in the Body
The Energy-YieldingNutrients: Carbohydiate,
Fat, and Protein
The Vitamins
The Minerals
Water
The Science of Nufiition
Conducting Research
Analyzing Research Findings
Publishing Research
Dietary ReferenceIntakes
Welcome to the world of nutrition. Although you may not always have been aware
of ir, nutrition has played a significant role in your life. And it will continue
to at_
fect you in major ways, depending on the foods you select.
Every day, several times a day, you make food choices that influence your
body's health for better or worse. Each day,s choices may benefit or harm your
health only a little, but when these choices are repeated over years and decades,
the rewards or consequencesbecome major. That being the case, paying close
attention to good eating habits now supports health benefits later. Conversely,
carelessnessabout food choices can contribute to many chronic diseasesI prevalent in later life, including heart disease, diabetes, and cancer. Of course,
some
people will become ill or die young no matter what choices they make, and
others
will live long lives despite making poor choices. For the majority of us, however,
the food choices we make each and every day will benefit or impair our health in
proportion to the wisdom of those choices.
Although most people realize that their food habits affect their health, they
of_
ten choose foods for other reasons.After all, foods bring to the table a variery
of
pleasures,traditions, and associationsas well as nourishment. The challenge,
then,
Estatrlishing Nutrient RecommendationsI
EstablishingEnergyRecommendations
Using Nutdent RecommendatioDs
Comparing Nutrient Recommendations
Nutrition Assessment
Nutrition Assessmentof Individuals
Nutrition Assessment ol populations
Diet and Health
ChronicDiseases
RiskFactorsfor ChronicDiseases
Highlight
I Nutrition tnformation and
Misinformatio[-On the Net and in the News
i) In genera[,
a chronicdiseaseprogresses
srowty
or with tittle change
andlastsa longtine. By
comparison,
an acutediseasedeve[ops
quickty,
produces
sharpsymptoms,
andrunsa short
course.
. chronos- time
. acute= sharp
is to combine favorite foods and fun times with a nutritionally balanced diet,
Food Choices
Peopledecide what to eat, when to eat, and even whether to eat in highly personal
ways, often based on behavioral or social motives rather than on in u*ua"r"r"
of nutritions importance to health. A variety of food choices can support good
health, and an understanding of human nutrition helps you make sensible selec_
tions more often.
Personal Preference As you might expect, the number one reasonpeople choose
foods is taste-they like certain flavors. Two widely shared preferencesare for the
sweetnessof sugar and the savorinessofsalt. Liking high_fat foods also appears
ro
be a universally common preference.Other prefereacesmight be for the hot pep_
pers common in Mexican cooking or the curry spices of lndian cuisine. Reseirih
nutrition: the science
offoodsandthe nutrientsand
othersubstances
theycontain,
andof theiractions
withjnthe body(inctuding
ingestion,digestion.
absorption,
transport,metabotism,
andexcretion).
A
broader
definitionjnctudes
the sociat,economic,
cutturat,
andpsychologicat
implications
of foodandeating.
foods:productsderivedfromplantsor animalsthat can
betakeninto the bodytoyietdenerqyandnutrients
forthe maintenance
of tifeandthe growthandrepairof
ttsSues.
diet: the foodsandbeverages
a personeatsanddrinks.
suggests that genetics may influence taste perceptions and therefore food
likes
and dislikes.r Similarly, the hormones of p."gnarr.y ,""- to influence
food crav_
ings and aversions (seeChapter l5).
Habit Peoplesometimes select foods out ofhabit. They eat cereal every mormng,
for example, simply becausethey have always eaten ce;eal for breakfast. fating'a
familiar food and not having to make any decisions can be comfortrng.
Ethnic Heritage or Tradition Among the strongest influences on food
choices
are ethnic heritage and tradition. people eat the foods they grew up eating.
Every
country, and in fact every region of a country, has its own typical foods and
ways
of combining them into meals. The ,Ameriian diet,, inclujei many ethnic
foois
from various countries, all adding variety to the diet. This is most evident
when
eating out: 60 percent of U.S. restaurants (excluding fast_foodplaces) have an
eth_
nic emphasis, most commonly Chinese, Italian, or Mexican.
Social Interactions Mosr people enjoy companionship while earing. Ir,s fun
ro
go out with friends for pizza or ice cream. Chapter 9 describes how people
tend
to eat more food when socializing with others. Meals are often social events,
and
sharing food is part of hospirality-regardless of hunger signals. Social customs
invite people to accept food or drink offered by a host or shaied by a group.
S
o
An enjoyabteway to tearn about other cultures is
to taste their ethnic foods.
Availability, Convenience, and Economy people often eat foods rhar
are ac_
cessible,quick and easy to prepare, and wirhin rheir financial means. Consumers
who vahre conveniencefrequently eat out, bring home ready_to_eatmeals,
or have
food delivered. Even when they venture into the kitchen, ih"y *u.,, ro prepare
a
meal in 15 to 20 minutes, using less than a half dozen ingredients_and
those
"ingredients"
are often semiprepared foods. such as carrneJ soups. Alternatively,
some consumers visit meal-preparation businesseswhere they can assembleseveral meals to feed their families from ingredients that have been purchased and
portionedaccording to planned menus.2Those who frequently prepare
their own
meals eat fast-food less often and are more likely to meet dietary guidelines for
fat,
calcium, fruits, vegetables,and whole grains.3
Consumer emphasis on convenience limits food choices to the selections
of_
fered-on menus and products designed for quick preparation. Whether decisions
based on convenience meet a person's nutrition needs depends on the choices
made. Eating a banana or a candy bar may be equally convenient, but the fruit
provides more vitamins and minerals and less sugar and fat.
Rising food costs have shifted some.orrru-"ir.priorities and changed
their
shopping habits. They are less likely to buy higher piiced convenience foods
and
more likely to buy less-expensive store brand items and prepare home_cooked
meals. In fact, rltore than 80 percent of U.S. consumers are eating home_cooked
meals at least three times a week.4
Positive and Negative Associations people tend to like particular foods
as_
sociated with happy occasions-such as hot dogs at ball games or cake and
ice
a1 brlthday narries. By the same roken, people can develop aversions and
1te-13
dislike foods rhat rhey are when they felt sick oi that they were forced to eat
as a
child. By using foods as rewards or punishments, parents may inadvertently
teach
their children to like and dislike certain foods.
Emotions Some people cannot eat when they are emotionally upset. Others
may
eat in response to a variety of emotional stimuli_for example, to relieve boredom
or de-pressionor to calm anxiety. A depressedperson may choose to eat rather
than
to call a friend. A person who has returned home from an exciting evening
out may
unwind with a late-night snack. Thesepeople may find emotiona'icomfori, in
pa.i,
becausefoods can influence the brain,s chemistry and the mind's response.
Carbo_
hydrate and alcohol, for example, tend to calm, whereas p.otein ani caffeine
are
more likely to activate.Eating in responseto emotions can easily lead to overeating
and obesity, but it may be appropriate at times. For example, sharing food ar
timei
of bereavementserves both the giver's need to provide ctmfort anj the receiver,s
need to be cared for and to interact with others, as well as to take nourishment.
iaiues Food choices may reflect people'sreligious beliefs, political views, or
environmental concerns. For example, some Christians forgo meat on Fridays
Juring Lent (the period prior to Easter),Jewish law includes an extensive set of
Jietary rules that govern the use of foods derived from animals. and Muslims fast
oetweensunrise and sunset during Ramadan (the ninth month of the Islamic calrndar). Somevegetarians select foods based on their concern for animal rights. A
:oncerned consumer may boycott fruit picked by migrant workers who have been
:rploited. People may buy vegetablesfrom local farmers to save the fuel and en';ironmental costs of foods
shipped from far away.They may
:lso select foods packaged in containers that can be reused
:r recycled. Someconsumers accept or reject foods that have
reen irradiated, grown organically, or genetically modified,
:epending on their approval of these processes(seeChapter
rnd Highlight 19 for a complete discussion).
=
;ody Weight and Image Sometimes people selecr certain
:..'odsand supplements that they believe will improve rheir
,-hlsical appearance and avoid those they believe milht be
:etrimental. Such decisions can be beneficial when based on
.-.und nutrition and fitness knowledge, but decisions based
:n fads or carried to extremesundermine good health, as
:ointed out in later discussionsof eating disorders (Highrsht 8) and dietary supplements commonly used by athletes
,-lighlight 14).
l;,Jtrition and Health Benefits Finally, of course,many
:..nsumers make food choices that will benefit health. Food
I
ranufacturers and restaurant chefs have responded to sci.ntific findings linking health with nutrition by offering an
:rundant selection of health-promoting foods and beverages.
@
-.rods that provide health benefits beyond their nutrient
To enhanceyour health,keepnutrition in nind whensetectingfoods.To
-.ntributions are called functional foods.5 Whole foods-as
protect the environment,shop at locat markets and reuse cloth shopping
:atural and familiar as oatmeal or tomatoes-are the sim- Dags,
:lest functional foods. In other cases,foods have been modi
ed to provide health benefrts,perhaps by lowering the fat contenrs. In still other
-:ses, manufacturers have fortified foods by adding nutrients or phytochemicals
:1at provide health benefts (see Highlight 13). i Examples of these Iunctional
) FunctionaI
foodsmayincLude
who[efoods,modi-rods include orange juice fortified with calcium to help build strong bones and
fied foods, or fortified foods.
:nargarine made with a plant sterol that lowers blood cholesterol.
Consumers typically welcome new foods into their diets, provided that these
:..ods are reasonablypriced, clearly labeled, easy to find in the grocery store, and
-.rnvenient to prepare.Thesefoods must also taste good-as good as the traditional
-hoices.Of course,a person need not eat any "special" foods to enjoy a healthy diet;
rany "regular" foods provide numerous health benefits as well. In fact, ,,regular,'
-rods such as whole grains; vegetablesand legumes;fruits; neats, frsh, and poultry;
rnd milk products are among the healthiest choicesa person can make.
I N SUMMARY
A person selects foods for a variety of reasons. Whatever
those reasons may be, food choices influence health. Individual food selections neither make nor break a diet's healthfulness, but the balance of foods
selected over time can make an important difference to health.6 For this reason, people are wise to think "nutrition" when makinq their food choices.
The Nutrients
:, -.eically speaking,people eat to receivenourishment. Do you ever think of
::.elf as a biological being made of carefully arranged atoms, molecules, cells,
.=res. and organs?Are you aware of the activiry going on within your body
functionaIfood5:foodsthat containphysiotogicatty
activecornpounds
that providehealthbenefitsbeyond
their nutrientcontrib!tions;sometimes
catteddesrgref
uticals.
foods ot nutroce
phytochemicat5
(FIE-toe-KE14-ih-caLs);
nonnutrjent
compounds
foundin pLant-derived
foodsthatflave
biotogicat
activityin thebody.
. phyto= ptant
molecules' and cells of
even as you sit still? The atoms'
even though
"..t, t.au contiluously move and change'
your. exand
organs
of your tissues and
lhJ t;".ltt"t
r skin'
ou
\
vel).
conitant
n relarr
,;;";i ;;;;rt""..'remai
r
e
p
l
a
c e de n i
s
w h i c h h a s c o v e r e dy o u s i n c e) o u r b i r t h
fat beneath your
tiTelv by new cells every 7 years The
ago Your
.t ir.r i, ttot the same fat that was there a year
entire
the
and
old'
days
120
is
only
oldest red blood cell
lining ol your digestive lract is renewed every 3 to 5 days'
"self,' you must continually rePlenish,
To m"aintain youi
f r o m f o o d s ,l h e e n e r g ya n d l h e n u t r i e n t 5 ; o u d e p l e t ea s
your body maintains itself.
Nutrients in Foodsand in the Body e-u'-
energy, structural
. ingly, our bcidies can clerive all the
from the foods
we
need
! mite.ials, and regulating agents
that foods
nutrients
"^,. This section introduces the
€
" *"
the
dynamic
in
d"hu", and shows how they participate
processesthat keep people alive and well
Foodsbring pteasure-andnutrients.
mostlipidsarefats.
5 exptains,
I AsChapter
of nutrients:
I sixcLasses
. Carbohydrates
. Lipids(fatt
. Proteins
. Vitamins
. llinerats
as a tomato
Nutrient Composition of Foods Chemical analysis of a food such
solid mateof
the
(95
Most
percent)
water
of
shows that it is composed primarily
materithese
remove
could
lf
you
I
proteins
and
rials are carbohydraies, hpids,
compounds'
other
and
minerals,
vitamins,
of
ui., yoo rvonld hnd a tiny residue
minerals found
Water, carbohydrates,lipids, proteins, vitamins, and some of the
11ses
for the
the
body
I
of
nutrients-substances
in foods represent the six clasies
its
tissues'
maintenance, and repair of
growth,
'
This book focuses mostly on the nutrients, but foods contain other compounds
others Some
as well-fibers, phytochemicals, pigments' additives, alcohols' and
of the book
Later
sections
harmful
few
are
n
are beneficial. som" ,." ,r"ur.ul, u,,d
I
h
e
i
r
5
i
S
,
n
i
h
c
a
n
c
e
r o u c ho n t h e . ec o m p o u n d sa n d
would
Nutrient Composition of the Body A chemical analysis of your body
(see
1-I)'
FiSure
show that it is made of materials similar to those found in foods
1,.:.:t..ir:'ll
lil,l';.;,'1.air
I "rou** ,-,
l'.:.lirlii:l,;jl:fi:ii:;
Body Compositionof Healthy-WeightMen and Women
simitarto thosefoundin foods-mostlywater
Thehumanbodyis madeof compounds
(60Dercent)andsomefat(l3to2lpercentforyoungmen,23to3lpercentfory
andotherminorconstituents
protein,vitamins,minerals,
with carbohydrate,
women),
of too little or too
hazards
health
the
describes
(Chapter
8
makingup the remai;der.
muchbodyfat.)
Key:
% Carbohydrate,
Prolginl
I
m neras Inlneoooy
vitamins,
to dowork.Theelerg!i" foodi'
enerqv:tre capacilv
thieche-nr(a
Tnebodycanconvert
enerqv.
.hemicat
or heatenergy.
etectricat,
to nechanjcat,
energy
obtainedfrornfoodand
substances
nltrients: chemical
materiats,
structuraI
energy,
usedin thebodyto provide
growtn,
malntenance,
to support
agents
andreguLating
andrepairofthe body'stissues.Nutrientsmayatso
therisksof somediseases.
reduce
;
o
!
z Fatin the oody
ffi
% waterin the body
-\ healthy 150-pound body contains about g0 pounds of water and abour 20 to 45
pounds of fat. The remaining pounds are moitly protein, carbohydrate,and the
major minerals of the bones. Vitamins, other minerals, and incidental extras con_
stitute a fraction of a pound.
Chemical Composition of Nutrients The simplest of the nutrients are the min_
arals.Each mineral is a chemical element;irs atoms are all alike. As a result. its
-dentity never changes. For example, iron may have different electrical charges,
but the individual iron atoms remain the same when they are in a food, when a
Dersoneats the food, when the iron becomespart of a red blood cell, when the
:ell is broken down, and when the iron is lost from the body bv excretion. The
rert simplest nutrient is water, a compound made of two elements-hydrogen
:nd oxygen. Minerals and water are inorganic nutrients, which means they do not
. ' n t a i nc a r b o n .
The other four classesof nutrients (carbohydrates, lipids, proteins, and vita_
:lins) are more complex. In addition to hydrogen and oxygen, they all contain
:,:rbon, an element found in all living things. They are therefore called orqanic
:-.mpounds (meaning, literally, "alive"). This chemical definition of orsanic dlffers
::om the agricultural definition. As Chapter 19 explains, organic
Jaring relers rc
-o$'ing crops and raising livestock according to standards set by the U.S. Depart_
=ent ofAgriculture (USDA). Protein and sornevitamins also contain nitrosen and
:rar contain orher elements such as sulfur as well (seeTable l_l).
o
=
=
;
lssential Nutrients The body can make some nutrients, but it cannot make
: , of them. Also, it makes some in insufficient quantities to meet its needs and,
-rerefore, must
obtain these nutrients from foods. The nutrients that foods must
:jpply are essential nutrients. When used to refer to nutrients, the word essential
]reans more than just "necessary"; it means ,.neededfrom outside the body,,_
-'rmally, from foods.
The Energy-YieldingNutrients: Carbohydrate,Fat, and
--fOIeIn
In
body, rhree organic nutrienrs can be used to provide energy:
-the
:=rbohydrate, fat, and protein. 0 In contrast to these energy-yielding nutrients,
: iamins, minerals, and water do not yield energy in the human body.
lf,ergy Measured in kCalories The energy released from carbohydrate, fat.
:.d protein can be measured in calories-tiny units of energy so small that a sin_
=: apple provides tens of thousands of them. To ease calculations, energy rs ex_
::essed in 1000-caloriemetric units known as kilocalories (shortenedto kcalories,
-l commonly called "calories"). When you read in popular books or magazines
TABLE
r-r Elements in the Six Classesof Nutrients
\rtice that organicnutrjentscontat'n
carbon.
Carbon
Nydroger
:-organic
rulrlents
i'ietats
oxygen
Nitrogen
Minerals
I Carbohydrate,
fat, and protejn are sometines
caltedmacronutrients becausethe body requires
themjn reLativety
[argeamounts(manygrams
daity).In contrasL,
vitaminsand mineralsare
rnicronutrients,requjredonlyin snat[amounts
(mitUgrams
or nicrograms
daity).
inorganicnotcontaining
carbon
or pertainjng
to fiving
things.
organic:in chemistry,
a substance
or motecule
containing
carbon-carbon
bonds
or carbon-hydrogen
bonds.
Thisdefinition
excludes
coal,diamonds,
anda
fewcarbon-contajning
compounds
thatcontain
ontya
singte
carbon
andro hydrogen,
suchascarbon
dioxjde
(C02),
catcium
carbonate
(CaCoJ,
magresium
carbonate
(MgCoJ,
andsodjum
(NaCN).
cyanide
essentialnutrients:nutrjentsa personmustobtain
fromfoodbecausethe
bodycannotmakethem
foritsetf
in sufficientquantitytomeetphysjologjcaI
neeos;arso
cattedindispensabte
nutrients,About40 nutrjentsare
currentty
i<nown
to beessentiatfor
human
beings.
energy-yietding
nutrients:the nutdentsthat break
downtoyietdenergythe
bodycanuse:
. Carbohydrate
. Protein
r*-aminsb
/
,
'r:-: rroteinsalsocontainrhe nineralsulfur,
r:_: /itanins containnjtrogen;somecontainminerats,
aatoriest
unitsbywhich
energyis
measured.
Food
jn krlocololieJ
energyismeasured
(1000caloriesequaL
1 kjtocatorie),
abbreviated
kcalodesor kcat.One
kcatorie
is theamount
of heatnecessaryto
raise
the temperature
of 1 kjlogram(kg)ofwater1.C.The
scientificuseofthe termkcalone
is the sameasthe
poputaruseofthe termcolorie.
_!
t-
.} TheinternationaI
foodenergy
unitfor rneasurinq
Toconof uorkenergy.
is thejoute,a measure
muttiply
by4.2;t0
to kilojoules,
vertkca[ories
by0 24.
multipLy
to kcalories,
kilojoutes
conveft
"100 calolies,"it actuall)'means 100kcalorie-sThis book
that an apple provides
uses the ier-m kcalorie and its abbreyiatiotr kcal throughout, as clo olher scientrhc
"llow To" providesa few tips on "thir.rkboohs andjournals i' The accomPan)'ing
ing metric."
Think Metric
nutrition
Likeotherscientists,
scientistsusemetricunitsof measure
foodenergyin kitocalories,
Theymeasure
peopte's
people's
heightin centirneters,
andthe weightsof
weightin kitograms,
foodsandnutrientsin grams,mittiqrams,
Foreasein usingthese
or micrograms.
that the
it helpsto remember
measures,
prefixes
on the gramsimpty1000.For
a k ogramis 1000grams,a mllliexamp[e,
gramis 1/1000of a gram,anda fficrogram
is 1/1000of a mittigram.
I4ostfood labetsandrnanyrecipebooks
"duaImeasures,"
[istingboth
provr'de
, c ha sc u p sq, u a r t s
h o r s e h o tm
d e a s u r esi u
such
andmetricmeasures,
andteaspoons,
liters.andgrams.ThispracasmilfiLiters.
tice givespeoptean opportunjtyto gradu"think metric."
at[ylearnto
Volume:Liters (L)
(mL)
1 t: 1000mitlititers
0.S5L=lquart
1mL= 0.03fluidounces
240mL=lcup
"think metA pefsonmightbeginto
the measure-by
ric" by simplyobserving
in a 2-titer
of
soda
amount
noticingthe
suchexThrough
for
example.
bottte,
famiIar
periences,
a personcanbecome
to
do any
having
measure
without
with a
conversions.
manY
Tofacjfitatecommunication,
scientific
internationaI
of the
members
haveadopteda commonsystem
community
System
lnternationaI
of measurement-the
metrrc
to
using
(SI).
In addition
of Units
commonun]ts
the SI estab|'ishes
measures,
the 51unit
For
exampte,
of measurement.
rood
joule
is
the
energy
i"g
for rneasur
Ajouteis the amountof
(notthe kcatorie).
Is moved
when1 kitogram
energyexpended
jouteis
The
1
newton.
:l meterby a forceof
the
whereas
energy,
of
work
thus a measure
of heotenergy.White
is a measure
kcatorie
journa[s
reporttheir
manyscientistsand
( ksJ ) ,m a ' r yo f h e r s .
f i n o i n q s ' kni L o j o u l e
, se
p a r t i c J l a rI,hy o s ei n t h e U n i t e dS t a t e ' u
(kcal).Toconvertenergymeakcalories
muttiply
to kitojoules.
suresfrom kcatories
b y4 . 2 .l - o re x a r n p l ae ,5 0 - k c a l o rci eo o k i e
provides210kilojoutes:
50kcalx 4.2: 210kJ
factorsfor theseand
Exactconversion
arein the Aidsto
otherunitsof measure
C a r c u L d Ls. eo Ln L i oo"rl t h e l a s tt w o p a g e \
o ft h eb o o k .
C E N G A G E, , l
F o ra d d i t i o n apl r a c t i c el o g o n t 0 w w w ' c e n g a g e
"ffi6
E
G)
0 n €c u pi s a b o u t2 4 0m i L L i L i t ear sh;a l f _ c uopf
l i q u i di s a b o u t1 2 0m i t t i t j t e r r '
A l i t e r o f t i q u i di 5 a p p r o x i m a t eot yn eu S q u a r t
t o r et h a n
( F o u rl i t e r sa r eo n i ya b o u t5 p e r c e nm
a gauon.)
Weight: Grans (g)
1 q = 1 0 0 0m i t t i s r a i r s( m g )
1 g = 0.04 ounce(oz)
1 o z : 2 8 . 3 5 S ( o r3 0 g )
1009=3t7.ot
1 k i l o q r a m( k s ) : 1 0 0 0g
1 k q = 2 . 2 p o u n d s( l b )
4 5 4g : I t b
F{ffi =.
ffi:
P n
oE
y o r et h a n
A k i l o g r a nj rs s L i g h t i m
2 t b ; c o n v e r s e tay ,p o u n di s a b o u t
V, kg.
A h a t f c u po f v € g e t a b l ews e i g h sa b o u t1 0 0
g r a m so; n ep e aw e j g h sa b o u t1 / ?g r a m
A 5 - p o u n db a go f p o t a t o e sw e i g h sa b o u t
2 k i t o g r a m sa,n da 1 7 6 - p o u npr le r 0 n w e r g r s
80 kjLograms.
to centimeters'
andyourheightfromlnches
to ki[ograms
yourbodyweightfrompounds
Convert
m
Calculate the Energy Available from Foods
TocaLculate
theenergy
avail
::le froma food,multiplythe number
'gramsof carbohydrate,
protein,and
=.rby4,4, and
9, respectjvety.
Thenado
:-e resuttstogether.Forexample,1 slice
:'bread with 1 tabtespoon
of peanut
: - r t e r o n i t c o n t a i n1s 6g r a m sc a r b o h y : - l t e , 7 g r a m sp r o t e i na, n d9 g r a m sf a t
:6 9 .d'bohyd'ale L lcal/g - 6t rcal
7 g proter'n
x 4kcaL/g: 28 kcaL
9 g f a t X 9 k c a y g : 8 1k c a t
Total= 173kcaL
:-!m this jnformatjon,you
can calculate
:-e oercenLage
of kcatorieseachofthe
::ergy nutrientscontributes
to the totat.
-:
determine
the percentage
of kcatories
r )n fat. for example,ivide
d
the 8i fat
. :aloriesbythe tota[ 173kcatories;
81fat kcal+ 173totatkcal= 0.468
(rounded
to 0.47)
Thenmuttiply
by100to getthe
percentage:
0.47x100:470k
Dietaryrecommendations
that urge
peopteto limit fat intaketo 20 to 35 percent of kcaloriesreferto the day'stotat
energyintake,not to jndividuatfoods.
Stitt,ifthe proportionoffat in each
foodchoiceLhroughout
a dayexceeds
35 percentof kcalories,
then the day's
total suretywitt,too. Knowing
that this
snackprovides
47 percentof its kcatories
fromfat atertsa personto the needto
make[ower-fat
selections
at othertime5
that day.
TABLE1-2 kCalorie Values
of Energy Nutrientsa
Nutrients
Energy
(kcatlg)
Carbohydrate
4
N0TE:Atcohol.ontributei 7 k.atofjesperqEm that caf,be tr\eo
forenergy,but it ls not considered
a nurrief,tbecause
ir interferes
, a i n t e n a n caen,dr e p a i r ,
w i t ht h e b o d y !g r o w t hm
: F o r t h o sues i n qk i t o j o u L el sq: . a r b o h ! d r a i=e
1 7k J ;
I g pfotein= 17 kJ; I g fat = 37 kJj and 1 q at.ohot= 29 tJ.
CENGAGEI]OW
ForadditjonaI practjce log on to www,cengage
Catculate
the energyavaitabte
froma beanburritowith cheese(55qramscarbohydrate,
ltl
15 gramsprotein,and12 gramsfat). Determine
the percentage
of
. :aLories
fromeachof the energynutrients,
-iJy iroin !-oods The amour.rtof energya food provides dependson how much
.::rohydrate, far, and protein it contains. l When completely troken down in the
-h. a gram of carbohyclrateyields about 4 k.alories o1 eneigy; a gram of protein
.-. r'ields 4 kcalories; and a gram of lat yields 9 kcalories (seeTable 1_2).The ac_
:rpanying "How To" explains how to calculate the energy availablefrom foods.
Secausefat provides more energ) per gram. it ha> a grearcr energy density
:-,n either carbohydrateor protein. Figure 1-2 (p. t0) comparesthe energyden_
. . o[ rwo breakfastoptions,and later chaptersdescribehow considerinqa food,s
::rgy density can help with weight management.I
Jire othcr substancecontributes energy-alcohol. Alcohol, hower,er,rs not
:riidereda nutrienr. Unlike the cssentialnutrients,alcoholdoesnot sustainlife.
tact, it interfereswith the growth, maintenance,and repair of the body Its
-,\ common characteristic
with nutrienrsis that it yields energy(7 kcaloriesper
-:.-n.r)when metabolizedin the body.
\1ost foods contain all three energy-yieldingnutrients, as well as \rlamrns,
:-nerals,water,and other substances.
For example,meatcontainswater,fat, vita_
: rns.and minerals as well as protein. Breadcontainswater, a trace of fat. a little
::-rrein, and some vitamins and minerals in addition to its carbohydrare.Only a
..r foods are exceptionsto this rule-the common onesbeing sugir (pure carbo_
. drate) and oil (essentially pure fat).
:..:rEy in the tsody The body uses the en€rgy-yieldingnutrienrs to fuel all irs
. -iivities.When the body usescarbohydrate,fat, or protein [or energy,the bonds
-:iNeenthe nutrient's aroms break. As tl.re
bonds break, they releaseenergy.I
::me oI this energy is releasedas heat, but some is used to send electricalim_
:--:lses
through the brain and nerves,to synthesizebody compounds.and to move
:-.:scles.
Thus the energyfron fooJ supporr, everl,acrivityfiorn quret thought to
iorous sports.
I Theenergy-yietding
nutnents:
. Carbohydrate
. Fat
. Protein
t Foodswith a high energydensjtyhetpwrth
weightgain,whereas
thosewith a low energy
densityhelpwith wejghtloss.
I Theprocesses
by whichnutrjentsarebroKen
downto yield energyor usedto makebody
structures
areknownas metabotisrn(defined
and described
furtherjn Chapter
7)
energydensity:
a measure
oftheenergy
a foodprovjdes
retative
to theamount
pergram).
of food(kcaLorjes
=
10
FrcuRE 1.2 Energy Density of Two Breakfast Options Compared
Gram
for gram,
ounce
forounce,
andbiteforbite,foodswitha highenergy
densjty
defiver
morekcatories
thanfoodswitha lowenergy
density.
Bothof thesebreakfast
provide
optjons
500kcatories,
butthecereal
withmitk,fruitsalad,
scrambted
egg,
turkeysausage,
andtoastwithjamoffersthreetimesasmuchfoodasthedoughnuts
(based
onweight);
it hasa lowerenergy
density
thanthedoughnuts.
Setecting
a varietvof foodsatsohetos
to ensure
nutrient
adeouacv.
e
e
@
LOWER
ENERGY
DENSITY
This450-gram
breakfast
deUvers
500kcatories,
for an energydensityof 1,1
(500 kcat+ 450g : 1.7 kcaL/g).
HIGHER
ENERGY
DENSITY
This144-gram
breakfast
defivers
500 kcalorjes,
for an energydensityof 3.5
(500kcat+ 144g: 3-5kcaL/g).
II the body does not use these nutrients to fuel its current activities, it converts
them into storage compounds (such as body fat) to be used between meals and
overnight when fresh energy supplies run low. lf more energy is consumed than
expended, the result is an increase in energy stores and weight gain. Similarly, if
less energy is consumed than expended, the result is a decreasein energy stores
and weight loss.
When consumed in excess of energy needs, alcohol, too, can be converted to
body fat and stored. When alcohol contributes a substantial portion of the energy
in a person's diet, the harm it does far exceeds the problems of excessbody fat.
(Highlight 7 describes the effects of alcohol on health and nutrition.)
Other Roles of Energy-Yielding Nutrients In addition to providing energy,
carbohydrates,fats, and proteins provide the raw materials for building the body's
tissues and regulating its many activities. In fact, protein's role as a fuel source is
relatively minor compared with both the other two energy-yielding nutrients and
its other roles. Proteins are found in structures such as the muscles and skin and
help to regulate activities such as digestion and energy metabolism. (Chapter 6
presents a full discussion on proteins.)
The VitaminS
The vitamins are also organic, but they do not provide energy. Instead, they facilitate the releaseof energy from carbohydrate, fat, and protein and participate in numerous other activities throughout the body.
Each of the 13 vitamins has its own special roles to play.n One vitamin enables
the eyesto seein dim light, another helps protect the lungs from air pollution, and
still another helps make the sex hormones-among other things. When you cut
yourself, one vitamin helps stop the bleeding and another helps repair the skin.
Vitamins busily help replace old red blood cells and the lining of the digestive
tract. Almost every action in the body requires the assistanceof vitamins.
vitamins:organic,essentiaI
nutrjentsrequired
in smatt
amounts
bythebodyfor heaLth.
*Th€ wateFsoluble ritamins are vitamin C and Lhe eighl B vitamins: ihiahin, riboflarin, niacin, vilamins 86
and BD, folate, biotin, and pantothenic acid. The tat soLuble vitamins are vilamins A, D, E. and K. The watersoluble vnamins are lhe subjecr ot Chapter r0 and rhe fat soLuble viramins, of chaplei ll.
u
. riamins can function only if they are intact, but
becausethey are complex
::::ric molecules,they are vulnerableto destructionby heat, light, and
chemi_
i- :gents. This is why the body handles them carefully and whi nutntion_wise
,-:--.. do, too. The strategies of cooking yegetablesat moderate temperatures
for
::::: rimes and using small amounts of water help to preserve the vitamins.
=
]he.MinefalS
tn the body, some minerals are put together in orderly arrays
: .:ch srructures as bones and teeth. Minerals are also found in the fluids of the
:, ':'. 1\hich influences fluid balance and distribution. Whatever their roles.
min_
.---i.'Jo nor 1 ield energy.
-1nlr' 16 minerals are known to be essential in human nutrition.* Others are
:F:: studied ro determine whether they play significant roles in the human
body.
>- other minerals, such as lead, are environmental contaminants that displace
- rntriem minerals from their workplaces in the body, disrupting body iunc_
r-':. The problems causedby contaminant minerals are described in- Chapter
13.
l.:ause minerals are inorganic, they are indestructible and need not be han_
: r: rrth the special care that vitamins require. Minerals can, however, be
bound
:- .rbsrances that interfere with the body's ability to absorb them. They
can also
t ,ost.during food-refining processes or during cooking when they leach into
-::er rhat is discarded.
il{atef
Wate. ptovides rhe environment in which nearly all the body,s acriviries
::: ionducted. lt participates in many metabolic reactions and supplies the
me_
:,:m for transporting vital materials to cells and carrying waste pioducts a-ay
-::D rhem.
Water is discussed fully in Chapter fZ, bui itls mentioned in every
-:-:Dter. If you watch for it, you cannot help but be impressed by water,sparticipa_
r in all life processes.
: :; S UMMARY
Foods provide nutrients-substances thar support the
:rowth, maintenance, and repair of the body! tissues. The six ciasses of
uutrients include:
. Carbohydrates
. Vitamins
. Lipids (fats)
. Proteins
. Minerals
. Water
Foods rich in the energy-yielding nutrients (carbohydrate, fat, and protein)
provide the major materials for building the body,s tissues and yield energy
forthe body's use or storage. Energy is measured in kcalo.ies. Vitamins, min_
:rals, and water facilitate a variety of activities in the body.
:hout exaggeration,nutrients provide the physical and metabolic basis for
::,:rlr all that we are and all that we do. The next section introduces the science
of
::rition with emphasis on the researchmethods scientists have used rn uncover,
:: rhe wonders ol nutrition.
Water itsetf is an essentiaInutrient and naturallv
carriesmanyminerats.
The Scienceof Nutrition
l:-i scienceofnutrition is the study o[ the nutrients and other substancesin foods
,.-d the body's handling of them. Its foundation dependson severalorher
sci_
..-;es. including biology,biochemisrry.and physiology.As sciencesgo, nurrrrron
. r oung, but as you can see from the size of this
book, much has happened in
,':Iion's short life. And it is clrrrently experiencing a tremendous g.owth
spurt
-.. .-rentists apply knowledge gained from sequencing the human genome. The
. -.rior mineralslre calciurn, phosphorus, porass,um, sod,um. chtoride,
rnasnesrum, and sllrate. The rrace
: : . : . ; a r e i . o n , l o d i n e , z i n . . c h r o n i u n . s . L e n , u m ,f l u o n d e , m o t ) b d e n u m ,
r o p ; e , , r n . l u a n s a n e s e .c h a p r e . s
r c r h pa " j o r i n o I d . e m , n e r i i . r e . D e . \ ( t \ .
minerats:
inorganjc
etements.
SomemineraLs
are
jn snallanrounts
essential
nutrients
requjred
bythe
bodyforheaLth.
genome
(GEE-nome):
thecompLete
setofgenetjc
(DNA)
material
in anorganism
or a cett.Thestudyof
genomes
is catted
genomics.
t2
biology ha.s,oP-eneda whole
integration of nutrition, genomics, and molecular
scienceof how nutrients afnew world of study called nutritional Senornics-tht
between diet and
interactions
if genesand how geies af{ecr the
ii- ,fr" ^"*1,*t
the science
shaping
is
atr""r".; ttchftght 5 describes hoi nutritional Senomics
later
throughout
"xamples of nutrient-gene interactions appear
"il"irni"",1"i
sections of the book.
Conducting
or eventis
accountof an experience
a A DersonaI
sciretiable
as
accepted
an anecdoteand is not
entific information.
. anekdotos= unpublished
Resgarch
maydependon personalexperience
consumers
researchersuse
I to gather information on nutrition' but
ft"-it""ds
"ti"p"t"
figure shows'
thc
As
(see Figure l-3)
rhe scientific method to guide their work
"What foods
question For example'
r"r""r.lt "t*uy, t"glns with a problem or a
answer'
against the common cold?" In search-of an
o, ,to,rt""o -ighipro,".,
""r,
"foods rich in vitamin C
iucated guess (hypothesis) such as
..i".r,ir,, -^t "
,yrt"-utlcally conduct research
reduce the number of common colds.i ih"r, th"y
(see the glossary for definii" .. -, data that will test the hypothesis
,i"J*
t..
I "rou*" r-. TheScientificMethod
new
generates
fotlowthe scientificmethodNotethat mostresearch
scientists
Research
in
continues
research
and
anew'
begins
sequence
Thusthe
q""rii""r, "", fi*L answers.
waY.
cYcticaI
a somewhat
ANDOUESTION
OBSERVATION
ldentifya problemto be solvedor ask
a specificquestionto be answereo
t
t
ANDPREDICTION
HYPOTHESIS
a hypothesis-atentative
FofmuJate
solutionto the problemor answ-er.to
the question-andmakea pfedLctlon
ihatcan be tested.
I
+
EXPERIMENT
Desiqna studyandconductthe
rese;rchto collectrelevantdata'
i.t
g
V
ANDINTERPRETATIONS
RESULTS
analyze,and interprei
Summarize,
thedata;drawconclusions
.//
{
,
\
SUPPORTED
HYPOTHESIS
s c i e n c eo f h o wr u l r i e a l (
n u t d t i o n a l g e n o m i c sl h e
a t i e c t t h e a c t i v i t i e so l q e r e s( n u t r i g e n o m i c s )a n dh o w
g e n e sa f f e c t t h ei n t e r a c t i o n sb e t w e e nd i e t a n dd i s e a s e
(nutrigenetics).
DeveloPa theory that integrates
conclusionswith those lrom
numerousother studles
NEWOBSERVATIONS
ANOOUESTIONS
l3
TABrEr-3 Strengthsand Weaknessesof ResearchDesigns
: af Resea
rth
Strenglhs
Weaknesses
:ridemiologicatstudiesdetermine
the incroence
.-: ristrjbutionof diseases
in a poputatjon.
tpj::-'r.ogicat studiesinctudecross,sectionat,
case:: :'lr, and cohort(seeFigure1-4).
. Cannarrowdownthe Listof possiblecauses
. Ca1raisequestions
to pu-sue
rhrougnolre.
typesof studies
-:boratory-based
studiegexpLore
the effectsof
. ,:::jfic variabteon a tjssue,cetL,or motecule.
,,:r'atory-basedstudiesare oftenconducted
in
_ : i : : r b e s( i n v i t r o )
oronanjmals.
-Jfian interventionor ctinicattrials invotve
,-:_ beingswhofottowa specjfied
regimen.
. Cancontrolconditions
. Candetermr'ne
effectsof a variabte
. Cannot
controlvariabtes
that mayjnfLuence
the developrnert
or the preventjon
of a
drseaSe
. Cannot
causeandeffect
. Cannot
apptyresutts
fromtesttubesor
anjmats
to humanbejngs
. Cancontrolconditjons
(forthe mostpart)
. Candpplyfirdi-gr to sonegroupsot hunan
beings
Cannot
generatize
findjnqs
to allhuman
beings
Cannot
usecertaintreatments
for chnicalor
ethicatreasons
. -.i researchtenr.rs).Becauseeach type of study has strengths and weaknesses,
:. :rovide shonger evidencethan others (see Table l_3). Some examplesof
-: -: tvpes of researchdesignsare presentedin Figure l_a (p. f+).
----..iremptingto discover
whether a nutrient relieves symptoms or cures a dis_
:-: ::searchersdeliberatelymanipulareonr variablc ([or example.the amount
-,.nin C in the diet) and measureany observedcharges(perhapsthe number
;s r.As n.tuchas possible,all other conditionsare helclconstant.The follow_
:: ,:agraphsillusrratehow this is accomplished.
ai! In studiesexamining the effectiveness
of vitamin C, researcherstypi_
:ilide rhe subjects into two groups. One group (the experimental group)
., ::> a r,irarlin C supplement,and the other (the control group) does not. Re_
'- -:rs observeboth
groups to determinewhether one group has lewer,milder,
. - ::ier colds than the other. The following discussiondescribessorneof the
- - . inherent
in an experiment of this kind and ways to avoid them.
- iorting subjectsinto two groups, researchersmust ensure that each p€r_
- -:s an equal
chance of being assignedto either the experimental groui or
- rtrol group. This is accomplishedby randomization; that is, the subjects
': . -r5enrandomly
from the same population by flipping a coin or some other
-. -:.1 involving
chance.Randomizationhelps to ensurethat the two groupsare
,:- and that observed differences reflect the treatment ancl not othe'r factors.S
,
..
'l'.lrl;,,
1 _: experiment:
anexperirfent
- : :hesubjects
donotknow
_:: --:rey aremembers
of the
: : - : n t a t g r o uopr t h ec o n t r o I
(Thjsdoesnotmean
thatA causes
B orvjceversa.)IfA
increases
as
B decreases,
orifA decreases
asB
jncreases,
the correlation
is negative.
(ThisdoesnotmeanthatAprevents
B
orviceversa.)
Some
thirdfactornay
account
forbothA andB.
double-blind
experiment:an
experiment
in whichneitherthe
subjects
fortheresearchers
know
:_:'Et group:a groupotindivjduals whjchsubjects
aremembers
ofthe
- .-'- ailpossibLe
respects
to
expenmeitat
groupandwhjchare
. : ,:':mentatgroupexcept
for
serving
ascontrolsubjects,
untjl
: : :-:::.rent.IdeaLLy,
js over,
thecontrol
afterthe€xperiment
,: -:.jvesa pLacebo
whit€the
. :. :rtaI groupreceives
experimentaI
group:a groupof
a feal
jndividuats
jn aLL
simitar
possjbte
respects
to thecontroI
groupexcept
-:lrtion
=
(C0RE-ee-LAY-Shun):
the forthetreatment.
Theexperimentat
:: -eousincrease,
decrease,
or
groupreceives
thereaL
treatment.
:,= _ twovariables.
If Aincreases
-.as€s,
j-POTH-eh-sis):
:
orifA decreases
hypothesis
(h
asI
an
- !:::!, thecorrelatjon
is pojifiye.
unprovei
statement
thattentatjveLy
jpsbetween
exptains
theretatjonsh
twoor morevariabtes,
jn which
peerreview:a process
a panet
of scjentists
rjgorously
evaluates
a research
studytoassure
thatthescientific
method
was
followed.
placebo(pLa-SEE-bo):
anjnert,
harmtess
nredjcatjon
givento provjde
comfort
ard hope;a sharn
treatment
usedin controtted
research
studi€s.
ptaceboeffect:a chanqe
thatoccurs
in response
to expectations
about
the effectiveness
of a treatment
thatactuatty
hasnopharmaceutjcaI
effects.
randomization
(RAN-dorn
ih-ZAYshun):a process
ofchoosingthe
rnernbers
of theexperimental
and
groups
controL
withoutbias.
replication(REPLih-KAY-shui):
repeating
anexperiment
andg€ttjng
thesarne
resutts.
5ubjects:thepeopte
oranimats
particjpatjng
project.
in a research
theory:a tentatjve
exptanatjon
that
rftegrates
manyanddjverse
findings
to furtherthe
understandjng
ofa
definedtopic.
vatidity(va-LID-ih'tee):
having
the
qualityofbeing
founded
onfactor
variables:
factors
thatcharge.
A
valiabte
maydepend
onanother
varjabte
(forexanrple,
a chjtd's
heightdepends
on lrjsage),orit
naybeirdependent
(forexarnple,
a chiLd's
hejghtdoesnotdepend
oi
th€cotorof hereyet.Sometjmes
bothvariabtes
corretate
witha thifd
variabte
(achjtd's
heightandeyecotor
bothdepend
on genetjct.
=
;
14
I
I
Designs
I rrcune r-l Examplesof Research
STUDIES
COHORT
SlUDlES
CASE-CONTROL
CROSS.SECTIONAL'STUDIES
o
E
observehow muchand whal
Researchers
krndsofioods a groLlpof peopleeat ano
ho\^hear'hyl^ose oeooleo'e l'e r f cdi^gs
identifyfactors that rnight inlluencethe
In vanous
incidenceof a dLsease
popuLatlons
I
L
@
Researcherscompate peopJewho do and
do not havea givenconditionsucn as a
disease c osely matching them n age,
oender,and otherkey variablesso tnal
;lfferences in other factors wlll stand out'
These dlfJerencesmay accounl lor lne
condition in the grouP that has it
Exampte.Ma.y peap\e in lhe l/lediterranean region drlnk more wlne eat more
fat from olive oil and yet have a lower
ncidenceol heartdlseasethan northern
Europeansand NorthAmerlcans
Example.Peoplewith gojter lack iodine
in theirdiets.
LABORATORY-BASED
STUDIES
INVITRO
LABORATORY-BASED
STUDIES
ANIMAL
Bloodcholesterol
Researchersanalyzedata collected lrorn
a selectedgroupof people(a cohort)at
inlervalsoveTa certalnperlodot time
Example.Da'aca ec'ed oer oo'cdllvover
Lhepa<-severaloecades1om ove'5000
rl_eLo!v'o'
oeooF ra^oo'"]'vselecteolrorn
'l
F-am'^qhamlvassa.^usetLs 1948have
reveale-dthat the risk of heart attack
ol l_c'easFs
increasesas o ooo cFoLe5te
HUMANINTERVENTION
(oRclrNlcAL)TRIALS
-E
E
q
b
d
s
o
feed an malsspecialdiets
Researchers
that provideor omit specfic nutrjents
and lhen observeany changesin heath
Such sludies tesl Possble disease
and lreaimentsln a Laboratory
caLrses
whereall conditlonscan be controlleo
Example.l\4icefed a hlghjat dret eat
lesslood than mice qlvena ower-lal
diet, so they receivethe same number
ol kcalories-but the mice eatlng tne
fat-rich diet becorne severelyooese
Researchersexaminethe effects ol a
specjficvarab e on a tlssue,cell' or .
moleculesolatedfroma livingorganlsm'
'sh
li'o trat
sLudies
Exanple I aoa'a|re t\
oils inh bit the growlh and activityof lhe
bacteriairnplcatedin ulcerlormaton
ask peopleto adopta.new
Reseafchers
rrull
behavior(forexample,eat a cLtTUs
or exerclse
take a vitaminC supplement,
dailv).Thesetrias heLpdelermrnetne
efie;tveness of such intervenlionson lne
of disease
or prevention
development
Example Heart disease rlsk factors lffltlrove when men receiveiresh-squeezed
oranqe i.l ce dai,y or Iwo morrhs co^-lod'ed
w Ir.ihose oa d o et low n vltar'l' C even
when both qfoups lollow a diet high in
satLlraleolar.
must,have the same
Importantly, the two groups-of people must be similar,and
the possibility that observed differtrack record with respect to colds to ;le out
might have occurred anyway lf'
ences in the rate, severity, or duration of colds
catih twice as many colds as the
lor example, the control group would normally
group, then the findings Prove nothing
experimental
also be siminvolving a nutrieint' the diets ol both groups must
ir, "*p"ri-!rl,.
the expenin
studied lf those
if".. "roi.inffv *ith ,especi to the nutrient being
:trEr[al group were receiving less vitamin C from their usual diet, then any effects
ir :r]e supptement may not tre apparent.
*::ple
Size To ensure that chance variation between the two groups does not
ui:ence the results, the groups must be large. For example, if o-nemember of a
r=r:p of five people catches a bad cold by chance, he wilipull rhe whole group,s
.Feragetoward bad colds; but if one member of a group of 500 catchesa bad coid,
de x-ill not unduly affect the group average.Statistical methods are used to deter_
me whether differences between groups of various sizes support a hypothesis.
l!6cebos lf people who take vitamin C for colds believeit will cure rhem. their
rfrrmes of recovery may improve. Taking anything believed to be beneficial may
hxru recovery. This phenomenon, the result of expectations. is known as the
effect. In experiments designed to determine vitamin C.s effect on colds,
lhbo
fte mind-body effect must be rigorously controlled. Severity of symptoms is o[_
h E subjective measure, and people who believe they are receiving rreatmenr
mr report less-severesymptoms.
df.'lq!
Lh{'e
de nst know (are blind to) wherher they are membeis of the experimental
receiving treatment) or the control group (receiving the placebo).
Blind When both the subjects and the researchers do not know which
r are in which group, the study is called a double-blind experinent. Berng
human beings and having an emotional and sometimes financial invest_
m a successfuloutcome, reseaichersmight record and interpret results with
i r-n the expected direction. To prevent such bias, the pilli are coded by a
partr'. rvho does not reveal to the experimenters which subjects are in which
r mtil all resultshavebeenrecorded.
ReSeafCh Findings
Research
findingsmusrbe analyzed
with an awarenessof each study's limitations. Scientists must be
about drawing any conclusions until they have accumulated a bodv of
fiom multiple studies that have used various rypes of research desilns.
:ace accumulates,scientists begin to develop a theory that integrates the
Fndings and explains the complex relationships.
tions and Causes Researchersoften examine the relationships between
nore variables-for example, daily vitamin C intake and the number of
r lhe duration and severity of cold symptoms. Importantly, researchers
b able to observe, measure, or verify the variables selected.Findings some_
no correlation between variables (regardlessof the amount of vita_
cmsumed, the number of colds remains the same). Other times. studies
a positive correlation (the more vitamin C, the more colds) or a neqa_
rtion (the more vitamin C, the fewer colds). Notice that in a positive
both variables change in the same direction, regardlessofwheiher the
is -more" or "less"-"the more vitamin C, the more colds,,is a oositive
L just as is "the less vitamin C, the fewer colds.', In a nesative correlatwo variables change in opposite directions: .the less vitamin C. the
b- or "the more vitamin C, the fewer colds.,'AIsonotice thar a oositrve
does not necessarily reflect a desired outcome, nor does a negative corars reflect an unwanted outcome.
evidence proves only that variables are associated,not that one
se of the other. People often jump to conclusions when they notice cor_
Lot their conclusions are often wrong. To actually prove thai A causesB,
15
z
o
=
t6
scientistshavetofindevidenceofthemechanism-thatis,anexplanationofhow
A might causeB.
F
a
Knowtedgeabout the nutrienis and their effects
on heatth comesfrom scientific studies.
Cautious Conclusions When researchersrecord and analyze the results oftheir
For
experiments, they must exercise caution in their interpretation of the findings
the
of
segrnent
a
specific
may
use
scientists
study,
"tu-pI", in ur.,"pidemiological
conclusions'
draw
scientists
the
When
years
old
30
popuLtion-say, men 18 to
perthey are careful ttot to generalizethe findings to all people Similarly' scientists
to
findings
their
applying
in
cautious
are
animals
for-ing research studies using
and
tentative
always
are
study
,","urch
o.ta
f-urry
humaribeings. Conclusions
As
take into acc"ountfindings from studies conducted by other scientists as well
recommendations
making
about
evidence accumulates,scientists gain confidence
that affect people's health and lives. Still, their statementsare worded cautiously'
'A ileihlgh in fruits and vegetablesmay protect against somecancers"
such as
one research question' they
Quite often, as scientists approach an answer to
are never lacking Furprojects
research
future
raise several more questions, so
"What subsuch as
questions
to
answer
ther scientific invesiigation
"within then seeks
fruits and vegetablesprovide protection?" lf those
stance or substances
then
substancesturn out to be the vitamins found so abundantly in fresh produce'
"How much is needed to offer protection?" "How do these vitamins protect agarnst
"ls it their action as antioxidant nutrients?" "If not, might it be another
cancer?"
action or even another substance that accounts for the protection fruits and vegquesetablesprovide against cancer?" (Highlight 11 explores the answers to these
disease
and
)
nutrients
tions and reviewJ recent research on antioxidant
Publishing
Reseafch
submitted
study-are
Thefindingsfroma research
the
to a board of riviewers composed of other scientists who rigorousll' evaluate
peer
as
known
process
followed-a
study to assure that the scientific method was
review. The reviewers critique the study's hypothesis' methodology, statistical
significance, and conclusions They also note the funding source' recognrzrng
9
th"atfinancial support may bias scientific conclusions lf the reviewers consider
research has
the conclusions to be welL supported by the evidence-that is, if the
journal
where othin
a
scientific
validity-they endorse the woik for publication
found
on the
information
ers can read it. This raises an important point regarding
review
Conpeer
of
scrutiny
lnternet: much gets published without the rigorous
and
the
data
examining
for
sequently, readeis mnst asst me greater responsibility
I
Highlight
citations
ofjournal
conclusiorrspre.ented-often without the benefit
1-4
Table
reliable
is
information
offers guidance in determining whether website
describes the parts of a typical research article
Even whena new finding is published or released to the media, it is still only
preliminary and not very meaningful by itself. Other scientists will need to conbody
hrm or disprove the finiings through replication To be accepted into the
TABLE1-4 Parts of a Research Article
. Absfro.t.Theabstractprovidesa brief overviewof the articte'
.Introduction.Ihehltoductionclearlystatesthepurposeofthecurrentstudy
. Review
reviewof the literaturerevealsa[[ that sciencehas
A comprehensive
of Litercture.
on the subjectto date.
uncovered
.Methodology..|henethodologysectiondefineskeytermsanddescribestheinstrumentsand
the study.
procedures
usedin conducting
.fiesulfJ.Theresultsrepo.tthefindingsandmayincludetabtesandfiguresthatslrrnmarizethe
information,
.Conclusiol?s.Theconctusionsdrawnarethosesupportedbythedataandreflecttheoriginat
andraiseseveral
a fewquestions
theyanswer
Usuat[y,
asstatedin the introductjon.
ouroose
more,
of thesubjectandshoutdinclude
s knowledge
. Rerelences.
reflectthe invesLigato.
Tnereierences
yearsotdaswetlascurrent
gtudies
('nctuding
several
keysfudies
an'extensive
tistor relevant
ones).
t6
ofhow
scientists have to find evidence ol rhe mechanism-that is, an explanation
A might causeB.
rir,,iri-iy
o
Knowtedgeabout the nutrients and their effects
on heatth comesfrom scientific studies.
their
Cautious Conclusions When researchersrecord and analyze the results of
For
findings
of
the
experiments, they must exercise caution in their interpretation
of
the
segment
""i-pl", ir.t un .pidemiological study, scientists may use a specifrc
conclusions'
draw
pop.,irtlor,-rny, men 18 to 30 years old. When the scientists
perihey are careful not to generalizethe findings to all people Similarly, scientists
to
findings
their
forming research studies using animals are cautious in applying
and
tentative
always
humarr"beings.Conclusions f-- uny ott" research study are
As
take into aciount findings from studies conducted by other scientists as well
evidence accumulates,scientisb gain confidence about making recommendations
that affect oeople'shealth and lives. Still, their statements are worded cautiously'
'A iieihigh in fruits and vegetablesmay protect against somecancers"
such as
one research question' they
Quite often, as scientists upp.ouih an answer to
Furraisi several more questions,;o future research projects are never lacking
"What subther scientific investigation then seeks to answer questions such as
stance or substances within fruits and vegetables Provide protection?" lf those
then
substancesturn out to be the vitamins found so abundantly in fresh produce'
"How
"How much is needed to offer protection?"
do these vitamins Protect agarnst
"Is it their action as antioxidant nutrients?" "lf not, might it be another
cancer?"
vegaction or even another substance that accounts for the protection fruits and
questhese
etablesprovide against cancer?" (Highlight 11 explores the answers to
tions and reviewi recent research on antioxidant nutrients and disease)
Publishing
Research
submitted
study.are
Thefindingsfroma research
the
to a board of r-eviewerscomposed of other scientists who rigorously evaluate
peer
as
study to assure that the scientific method was followed-a processknown
review. The teviewers critique the study's hypothesis, methodology, statistical
significance, and conclusions. They also note the funding source' recogmzlng
9
th"atfinancial support may bias scientific conclusions If the reviewers consider
has
the conclusions io be well supported by the evidence-that is, if the research
journal where othvalidity-they endorse the w;;k for Publication in a scientific
found on the
information
regarding
point
import;nt
raises
an
This
ers can read it.
review ConInternet: much gets published without the rigorous scrutiny of peer
the data and
for
examining
responsibility
greater
assume
must
sequently, readers
Highlight t
citations
ofjournal
benefit
the
wiihout
pr"r"rrted-often
.or,.ltrior.t,
Table 1-4
offers guidance in determining whether website information is reliable
describes the parts of a typical research article'
Even when a new finding is published or released to the media, it is still only
preliminary and not very meaningful by itself Other scientists will need to conbody
hr* o, dirpro-l" the finiings through replication To be accepted into the
TABLE1"4 Parts of a Research Article
. ,4bstrorf.Theabstractprovidesa brief overviewof the article'
.Introduction.Iheinltoductionctearlystatesthepurposeofthecunentstudy'
reviewof the literaturereveatsaltthat sciencehas
. Review
of lterotwe. A comprehensive
on the subjectto date.
uncovered
.MethodoLagy.Ihemethodologysectjondefine5keytermsanddesclibestheinstrumentsand
procedures
usedjn conductingthe study.
.Results.Theresu|tsreportthefindjngsandmayincludetablesandfiguresthatsumma
information.
.corclui,ons.Theconclusionsdrawnarethosesupportedbythedataandreflecttheorig
ihey answera few questionsandraiseseveral
DlrDoseasstatedjn the introduction.Usuatly,
more.
of the subjectandshoutdinclude
knowtedqe
. Refererces.
reflectthe investiqator's
Thereferences
yearsotd aswelLascurrent
(incLLrding
severaI
key
studies
studies
of
retevant
"n'exlensjvetlst
ones).
fi
'dminon
knowledge, a finding must stand up to rigorous, repeated testing in
qErrEenrs performed by several different researchers.What we ,,know', in nu_
uins re:ults from years of replicating study findings. Communicating the latest
Siin= 111
i15plepsr conrext wirhout disrorting or oversimplifying the messageis
rg&.o l<4gs for scientists and journalists alike.
t-:: each report from scientists, the field of nutrition chanses a little-each
contributes another piece ro the whole body of knowledge. people who
&
bo\' science works understand that single findings, like single frames in
)r
are just small parts of a larger story. Over years, the picture of what is
: nn nutrition gradually changes, and
dietary recommendations change ro
a rhe current understanding of scientific research. Highlight 5 provides a
ikd look at how dietary fat recommendations have evolved over the past sev*rzdes as researchershave uncovered the relationships between the varrous
o{ lat and their roles in supporting or harming health.
=
SUMMARY
Scientists learn about nutrition by conducting experiments
Sllos/ the protocol of scientific research. In designing their studies, rerandomly assign control and experimental groups, seek large samprovide placebos, and remain blind to treatments. Their findinqs
be reviewed and replicated by other scientists before being accepted as
of well-designed research have enabled scientists to study the
1511[nutrients in the body. Such researchhas laid the foundation for quannLrs much of each nutrient the body needs.
ReferenceIntakes
the results oI thousands of research studies, nutrition experts have pror.at ofstandards that defrne the amounts of energy,nutrients, other dietary
ents. and physical activiry that bcst support health. Thes-e-recomrrrcndarc .-alled Dietary Refeieirce IntdFes (DRI), and they ieflecr the collaborao[ researchers in both the United States and Canada.*I0 The inside
of this book provide a handy referencefor DRI values.
Nutrient RecommendatiOnSrn" DRtcommittee
'
E
of highly qualified scientists who base their estimates of nutrient needs
x e \ a m l n a L r o na n d l n t e r p r e t a l l o no l s c i e n l i h ce v i d e n c eT. h e s er e c o m j
'Jlpfly ro heahhype,ople
and iiraynor be appropriare-for
peoplewith
LhalIncrease
or decrease
nutrientnedd's.
The"riextseveralparagraphs
Aecific aspects of how the committee goes about establishing the values
up the DRI:
@
Dont let the DRI "atphabetsouD"of nutrien!
intake standardsconfuseyou. Their namesnaKe
sensewhen you learn their purposes.
Esnmared AverageRequirements (EAR)
hrrmmended
Dietary Allowances (RDA)
-ldequate Intakes (AI)
Iokrable Upper lntake Levels (UL)
Average Requirements
(EAR) The committee reviews hundreds
a nJ. roles in supporting various actiyities in the body and in reducing
r risks-rr
+Tlrnination of all the available data reveals that each person's body is
ead has its own set of requirements. Men differ from women, and needs
-':..
tr{:r.
rre produced by rh€ Food and Nutition Board. tnstiture ot Medicine ot rhe Nationat Acadrn\olvemenr ofscienrisrs lrom Canada.
DietaryRefeience
Intakes(DRI):a setof nutrient
intakevatuesfor heatthypeoplejn the UnjtedStatesand
Canada.
These
vaLues
areusedforptanning
andassessing
dietsandinclude:
. Estimated
Average
(EAR)
Requjrements
. Reconmended
Dietary
ALtowarces
(RDA)
. Adequate
(AI)
Intakes
. Toterabte
UpperIntakeLeveL5
(UL)
requirement:the lowestcontinuingintakeof a nutrient
thatwiLlmajntain
a specjfied
criterjon
ofadequacy.
t8
FrcuRE1.5 EstimatedAverageRequirements(EAR)and
RecommendedDietary Allowances (RDA)Compared
a personwith uniquenutrjtjonalrequireEachsquare
in the graphsbetowrepresents
threeof thesepeopte-A,B, andC.)Somepeopterequire
ments.(Thetext djscusses
fatl
onlya smattamountof nutrientX andsomerequirea [ot. f4ostpeopie,however,
in
middte,
somewhere the
a
o
o
E
z
E
z
for nutrieniX (un ts/day)
Da y requirement
Dar,yeq-irerrenl o aut'e1l y /u'iq/dar')
The Est mated Average Requirement
(EAR)fora nutrent s the amountthat
covershalfof the population(shown
hereby the red line)
DietaryA owance
The Recommended
(shownherein
(RDA)fora nLrtrlent
green)is set we abovethe EAR,
cover ng about 98o/.of the popLlation.
change as people grow from infancy through old age.For this reason, the comrnittee clusters its recqmmeDdationsfor people into groups based on age and gender'
Even so, the exact requirements for people of the same age and gender are likely
to be different. For example, person A might need 40 units of a particrllar nulrient
Aah a;t; p".ron n mlght need 35; and person C, 57. Looking at enough people
might reveal that their individual requirements fall into a symmetricai distribution, with most near the midpoint and only a few at the extremes (seethe left side
of Figure 1-5). Using this information, the committee determines an Estimated
Average Requi(ement (EAR) for each nutrient-the averageamount that appears
suffi.cientfor half of the population. ln Figure 1-5, the Estimated AverageRequirement is shown as ,+5units.
(EAR):the av€rage
EstimatedAverageRequirement
maintain
a specjfic
of a nutrientthatwiLL
dailyamount
physjoLogicat
function
in hatfthehealthy
bjochemicalor
group.
peopte
ofa gjvenageandgender
DietaryAtlowance(RDA):the average
Recommended
adequate
to meet
daityamou.tof a nutrjentconsidered
attheatthy
ofpracticaLLy
the kfowf nutrientneeds
'or
peop.e:
d 9od o'etaryi"tdkeovind'viduats.
whichatrnost
theamount
of a nutrientbetow
deficient:
peopte
to
overtime,
aLL
healthy
canbeexpected,
experience
deficiencysymptoms.
Recommended Dietary Allowances (RDA) Once a nutrient rcquirementis established, the committee must decide what intake to recommendfor everybodythe Recommended Dietary Allowance (RDA). As you can seeby the distribution
in Figure l-5, the Estimated AverageRequirement (shown in the frgure as'+5
units) is probably closest to everyone'sneed. However, ifpeople consumed exactly
the averagerequirement oI a given nutrient each day, half of the population would
develop deficiencies of that nutrient-in Figure l-5, for example, person C would
be among them. Recommendations are therefore set high enough above the Estimated AverageRequirement to meet the needs oI most healthy peopl€
Slnall amounts above the daily requirement do no harm, whereas amounts below the requirement may lead to health problems. When people'snutrient intakes
are consistentlydeficient (less than the requirenent), their nutrient stores decline, and over time this decline leads to poor health and deficiencysymptoms.
Therefore. to ensure that the nutrient RDA meet the needs o[ as many people as
possible,the RDA are set near the top end of the range of the population'sestimated requirements.
In this example, a reasonableRDA might be 63 units a day (see the right side
Figure
1-5).Such a point can be calculatedmathematicallyso that il covers
of
percent
of a population. Almost everybody-including person C whose
about 98
needs were higher than the average-would be covered il they rnet this dietary
goal. Relativelyfew people'srequirementswould exceedthis recommendation,
and even then. they wouldn't exceedby much.
-.r-i€quateIntakes (AI) For somenutrients, such as calcium, there is insuffi_
-z-::.cienriftcevidence
to determinean Eslimated
Average
RequirerTl*"rlt
i-ni.f,l
i::rded to r"t an RD1). In thesecases,the committeeaitebliift, urr7a"qr,ut"
h,rlie (AI) insteadof an RDA.An Al reflectsthe averaseamountof a nutrieni that
consumes.
rike rhe-Fo,q.
thfet ruy beusedasa nurrilgrrp,:f h:r 1.,_h
| .people
E[ :]al lor rndLvtcluals.
-i$ough both the RDA and the Al serve as nurrient intake soals lor individure rheir differences are noteworlhy. An RDA for a given nuirient is based on
oqsh scientific evidence to expect that the needs of almost all healthy people
i,fl 5€ met. An Al, on the other hand, must rely more heavily on scientific judgr..rr< becausesufficient evidence is lacling. The perc?ntageof people covered by
h.u t unknown; an-Ai ii expecrea to exieed ulr.r"g" ,eir.,i."-"nts, but it may
-ins
more or fe*eipeople than an RDA would cover (if an RDA could be detEr5aJ-for the-s?reasots, Al values are inore tentatiye than RDA. The table on
ft rn-ide front cover identifies which nutrients have an RDA and which have an
,f,- Lftr chapters present the RDA and AI values for the vitamins and minerals.
Eable
Upper Intake tevels (UL) As mentioned earlier, the recommended
tor nutrients are generousrand they do not necessarily cover every indih&c
fe.re,;ery nutrient. Nevertheless,it is probably best not to exceedthese rec|lbi
by very much or very often. Individual tolerancesfor high doses of
rzr1., and somewhere above the recommended intake is a Doint bevond
a rurrient is likely to become toxic.l2 This point is known as the Tolerable
Intake Level (UL). It is naive-and inaccurate-to think of recommendats drrnlmum amounts. A more accurate view is to see a Dersons nutrient
a falling within a range, with marginal and danger zones both below and
rt seeFigure 1-6).
artention to upper levels is particularly useful in guarding against the
of nutrients, which may occur when people use large-dose dinpplements and fortifred foods regularly. Later chapters discuss the danu i t h e x c e : s i v e l yh r g h i n r a k e so f v i r a m i n sa n d m i n e r a l s ,a n d t h e
ftou cover (p. C) presents tables of upper levels for selectednutrients.
Energy Recommendations
t9
FIGURE
1"6 Inaccurateversus
Accurate View of Nutrient Intakes
TheRDAor AI for a givennutrientrepresentsa pojntthat lieswithina rangeof
appropriate
andreasonabte
intakesbetween
toxicity and deficiency,Bothof theserecommendations
arehighenoughto provide
reservesin times of short-termdietaryinadequacies,
but not so highasto approach
toxicity. Nutrientjntakesaboveor below
thjs rangemaybe equatty
harmfut.
Inaccurate
view
Accurate
view
rn contrast
to theRDA
Energy Requirement (EER) The enerqyrecommendation-called
Macronutrient Distribution Ranqes (AMDR) peopledon,reat
nrh-: they derive energy from foods containing carbohydrates,fats, and
tach of these three energy-yielding nutrients contributes to the total
and those contributions vary in relation to one another. The DRI
has determined that the composition of a diet that provides adequate
untrients and reduces the risk of chronic diseasesis:
6i percent kcalories from carbohydrate
3i percent kcalories from fat
35 percent kcalories from protein
are known as Acceptable Macronutrient Distribution Ranges
=
Requirement
taXueslor nutrients, the recommendation for energy is not generous. Excannot be readily excreted and is eventually stored as body fat. These
nas be beneficial when food is scarce, but they can also lead to obesity
health consequences.
Energy Requirement (EER)-represents the averagedietary energy
per day) that will maintain energy balance in a person who has
hodr- rveight I and level of physical activity. Balance is key to the energy
Enough energy is needed to sustain a healthy and active life,
energy can lead to weight gain and obesity. Becausedlly amount in
trergv needs will result in weight gain, no upper level for energy has
=
I Reference
aduLts:
. [4en:19-30yr. 5 ft 10 in, and 154 tb
. Women:19-30 yr, 5 ft 4 in, and 726 tb
AdequateIntake (AI)t the average
dailyarfountofa
nutdentthat
appears
sufficientto
maintain
a specified
criterion;
a valueusedasa quidefor nutrjentintake
whenanRDAcannot
bedetermined.
TotetabteUpperIntakeLevet(UL):the maximum
dajty
amountof a nutrientthat appears
safefor mostheatthy
peopteand
beyond
whichtherejsanincreased
rjskof
adverse
heattheffects.
EstimatedEnergyRequirement
(EER):
the average
dietary
energyintake
thatmaintains
energy
batance
and
goodheatth
in a person
ofa givenage,gender,
weight,
hEight,andLevelof physicat
activity,
Acceptabte
MacronutrientDistributionRanges
(AMDR):
ranges
ofintakes
fortheenergy
nutrjents
that
provideadequate
energyandnutrientsandreducethe
riskof chronic
diseases.
z0
Using Nutrient Recommendations
theintentofnutrient
Although
recom;endations seems simple, they are the subject of much misunderstanding
and controversy. Perhaps the following facts will help put them in perspective:
;
1. t5tlmates 0I
I A registered dietitian (RD) and a dietetic technician, registered (DTR)are cottege-educated
who arequaljfood and nutritionspeciaLists
nutritionaIhealthand
fiedto evaluatepeop[e's
l
for
moreon whatconstineeds.SeeHr'ghtight
tutes a nutrjtionexpert.
and nutrient intakes aPPIYto
2. Recommend tions are not minimum requirements, nor are they nec
all individuals. Recommendations can target only
ilv ootimal intakffor
in txtrl
genetics'
about
knowledge
of
t66i.".rild6.iott
ent rreeds-yet. iiu"tt
to
the day may be fast approaching when nutrition scientists will be able
l3 Until then, registered
needs
nutrient
optimal
deter;ine an lndivlduil's
dietitians I and other qualihed health professionals can help determine lf
recommenclationsshould be adjusted to meet individual needs
-3.
Most nutrient goals are intended to be met through diets comPosedof a vari-
Bffis
"iy or;-a, *nineverpossible.
ih-eT?€IltEr more than just those nutrients covered by
tia;i,nnutftnfs,
the recommendations. Excessintakes of vitamins and minerals are unlikely
w h e n t h e yc o m el t o m f o o d . r a t h e rt h a n d i e t a r l s u p p l e m e n t '
e a i l y i n t a k e s l r y i n g l o m e e lt h e r e c o m 4 R e c o m m e n d a l i o nasp p l \ t o a v c r c g d
a n d u n n e c e s r a r vl.h e
ffiull
length o[ time over which a person's intake can deviate from the average
witiout risk of deficiency or overdose varies for each nutrient, depending
(such as
on how the body uses and stores the nutrient For most nutrients
thiamin and vitamin C), deprivation would lead to rapid development of
A
deFciency symptoms (within days or weeks); for others (such as vitamin
(over
or
months
and vitamin Brr), defrciencieswould develop more slowly
t
years).
rtll"?i"T"ti:'$"f
erraluatenutri"tion piogru-t for gtoups such as schoolchildren or military
oersonnel. The RDA (or Al if an RDA is not available) can be
Upper Intake Levels serve as a reminder
soals fo, in7;i;;;i;:Tolerable
tntak"-s below amounts that increase the risk of toxicity-not
[Apfitrr6t
a common problem when nutrients derive from foods, but a real possibility
for some nutrients if supplements are used regularly
With these understandings,prolessionalscan use the DR1for a variety of purposes
Comparing Nutrient Recommendations
naAt least+0different
tions a-ndinter-national organizations have published nutrient standards similar
ro those used in the United Statesand Canada.Slight differences may be apparent'
the stanreflecting differences both in the interpretation of the data from which
populaof
the
activities
physical
and
habits
dards *Jre derived and in the food
are
from FA0/WH0
l Nutrientrecommendations
1.
providedin Appendix
tions they serve.
Many countries use the recommendations developed by two international
(World Health
groups: FAO (Food and Agriculture Organization) and WHO
sufficient to
considered
are
6.su;ir"tiot.t). I The FAO/WHO recommendations
worldwide'
malntain health in nearly all healthy people
The Dietary ReferenceIntakes (DRI) are a set ol nutrient
II{ SUMMARV
intake values that can be used to plan and evaluate diets for healt\ people'
The EstimatedAverageRequiremenl{EAR) de6nesthe amount ola nulrient
The
that supports a specific function in the body for half of the populationAverage
Estimated
(RDA)
the
on
is
based
necommended Oietary Allowance
Requirement and estatlishes a goal for dietary intake that will meet the needs
of almost all healthy people. An Adequate Intake (AI) serves a similar Pur-
zl
rhen an RDA cannot be determined. The Estimated Energy Requirement
) defnes the average amount of energy intake needed to -uintrio
"o..gy
z
re, and the AcceptableMacronutrient Distribution Ranges(AMDR) defre proportions contributed by carbohydrate, fat, and protein to a healthy
Ih€ TolerableUpper Intake Level(UL) establishesthe hiqhestamount
p
z
safe for regular consumption.
=
Assessment
when a person doesn't get enough or gets too much of a nutrient or
Ifthe deficiency or excessis significant over time, the person experiences
ns of nalnutrition. With a deficiency of energy. rhe pe.son may develop
foms of undernuttition by becoming extremely thin, losing muscle tis_
hrcoming prone to infection and disease, With a deficiency of a nutriIErson may experience skin rashes,depression, hair loss, bleeding gums,
sms, night blindness,or other symptoms.With an excessof energl
rnaybecomeobeseandvulnerableto diseasesassociated
with overnuas heart disease and diabetes. With a sudden nutrient overdose, the
experience hot flashes, yellowing skin, a rapid heart rate, low blood
or other symptoms. Similarly, over time, regular intakes in excess of
also have adverseeffects.
tion symptoms-such as diarrhea, skin rashes, and fatique-are easv
rusethey resemblethe symptoms o[ other diseases.But"aperson*ho
how to use assessmenttechniques to detect malnutrition can identify
r conditions are causedby poor nutrition and can recommend steps ro
This discussion presents the basics of nutrition assessment:manv more
ollered in later chapters and in Appendix E.
Assessmentof
Individuals
To preparea nutririonas-
a registered dieritian; dietetic technician, registered; or other trained
professionaluses:
in[ormation
measulements
examinations
testS
3 methods involves collecting data in various ways and interpreting
in relation to the others to create a total picture.
IDformation One step in evaluating nutrition status is to obtain inebout a person's history with respect to health status, socioeconomic
ase, and diet. The health history reflects a person'smedical record and
. disease that interferes with the persons ability to eat or the body's
Lts.The person's family history of major diseasesis also noteworth%
cooditionssuch as heart diseasethar havea genetictendencyto run
Eco_nomiccircumstances may show a financial inability to buy enough
irods or inadequate kitchen facilities in which to prepare them. Social
as marital status, ethnic background, and educational level also influand nutrition status. A drug history, including all prescribed
medications, may highlight possible interactions that lead to
(as described in Highlight 17). A diet history thar examines
of foods, beverages,and dietary supplements may reveal either a
of nutrients or energy.
dict history, the assessorcollects data about the foods a person eats.
p be collected by recording the foods the person hu" "ut"n orr". u p"urs,3 days, or a week or more or by asking what foods the person
and how rnuch of each. The days in the record must be fairly typical
matnutrition:anyconditioncaused
byexcess
or
defrcjentfood
energyor nutrientjntakeor byan
imbalance
of nutrients.
. nal = bad
undernutritlon:deficientenergyor nutrients.
overnutrition:excess
energyor nutrients.
hutritior assessment:
a comprehensive
anatysis
of a person's
nutritionstatusthat useshealth,
socjoeconomic,
drug,anddjet histories;anthropometric
measurements;
physicaI
examinations;
andtaboratory
22
r..:.i,:....
,.:..
,.:
.. :",.,r:...
the Dietary Intake
FtcURE1.7 Using the DRI tO ASSeSS
of a Healthy Individual
zesmustbe recorded
sizes
s diet,andportionsi
persons
of theperson
ofthe
To detelminethe amountsol nuurentsconaccurately.
usuallyentelsthe foodsand theil
sumed,the assessor
I
::T:il1't::,1.,,,"Jililrff:il::T""*T:T
:i:"fi#il"ri#lr",rheDRrroAssessrheDierarvrntake
I
porl ion sizesinlo a computeru"ing a diet analysispro-
rh,s:,"p.:11:]::T,1:""::::lillL:T:
gram
n'1 ,rrj;,
rntake
ii:8ffi:il:Y:ii?JT"5l';l;io*"
h#n*"*:-"jt5*j:itr;jgl|
*ihi,'ffi[3#i##i#"
oeooe
Lhe'eeoso'al-.osta
above
falLs
usualintake
lf a person's
Hsh
t
I
I
-RDA-irua-
probably
adequate
adgry-at"
I
5; |I
EI
E L!i:[:,
5 |
:
I]
adequalebecausethe RDAcovers
people.
almosta tI peopte.
needsot atmost
the
ir'e neeos
rl,i. sren can alsobe done manually by lookup
each food in a table of food composition such as
rng
book The assessorthen compares
Appendix H in this book.
i n t a k t with the DRI to detern
u
l
r
i
e n l intakes
nutrient
t h e calculated
the
calculated
"-"-
","..;;ill":ffiitfti
mrne
rheprobabili,,
I
the :l::,::::1"rt::l|:li.ii*"Hffi
against
berween
comparedagainst
inrake
tha*ars
ff:.,:fJ[.',i;;tl:
be compared
Ausuar
might be
history might
diet history
the
the diet
rernaLivelv.
ternatively,
the
I1e
ldllsbetween
berweec
I Lalethat
Ihd lalls
A usual
rs-a'intake
I
or Dietarv
FoodGuide
suchastheUSDA
:strtJi","t#il,%::5""r';;8, standard;
GuidetinesJorAmett'""'1d-1:','1T]'::Yl\:l:l:^ffii;!?T+1";A'i";;;;q';;i
a
kom "
intakes from
inadequate
nutrient intakes
thatit ls inadequate
that
energy and nutrient
estimateof energy
An estimate
i :il1?,''t;x',i#,:l;,',:""1,,I
":ijjl"y."lifdl#'j"tlg.r"
I";;;jr"
cI
I
JJ:i;'::1il#ilfi|
i.l*fi'"','*T:;xT:t1f
:r';:"i'i"'?ii.ti
1ffi
-fffi
|
iHH""':#:il[til,ll
(chapter8presenr,,",",-ii;"":#IlT:[i:ff
includes growth charts lor children)
Measurements taken periodically and compared with previous measurements
but they
reveal patterns and indicate trends in a persons overall nutrition status'
ol
provide llttle information about specific nutrients lnstead' measurements.out
rn chlLdren'
iine with expectations may reveal such problems as growth tailure
that may
and
obesity-conditrons
in
adults,
tissues
body
of
wasting or sielling
reflect energy or nutrient deficiencies or excesses
A third nutrition assessment technique is a physical
Physical Examrnations
inspectron oI tne
examination looking for clues to poor nutrition status Visual
I
I
I
I
I
I
l
I
I
ft
anthroponetric(AN-throw-poe-14ET-rick):
suchasheiqhtand\aeitht.
. anthropos= human
. metric= measurinq
A peekinsidethe mouthprovidescluesto a person'snutrition 5
miy indicate a deficiencyof one of the B vitamins' and mottted
toricity. for exanpte.
trrs- skin, posture,tongue,and fingernailscan prorh clues.The examinationrequiresskill because FIGURE
r.B Stagesin the Development
;ftssicalsignsreflectmorerhan one nutrientdefi- of a Nutrient Deficiency
G toxicity-or even nonnutrition conditions. Like
assessmenttechniques, a physical examination
not yield firm conclusions. Instead, physical
reveal possible imbalances that must be
other
assessmenttechniques, or they con\
from other assessmentmeasures.
InternaIchangesprecedeoutwardsignsof deficiencies.
Howevetoutwardsignsof sicknessneednot appearbeforea persontakescorrective
measures.
Laboratorytests can hetpdeterminenutrient statusjn the
earlystages.
Tests A fourth way to derecta developing
WHATHAPPENSIN
THEBODY
WHICHASSESSI\iIENT
METHODSREVEALCHANGES
imbalance, or toxicity is to take samples of
uine, analyze them in the laboratory, and comrEsultswith normal values lor a similar populatests are most useful in uncovering early
before symptoms appear. In addican confirm suspicions raised by other assessThe mineral iron can be used to illusin the development of a nutrient deficiency
techniques useful in detecting them.
c outward, signs of an iron deficiency appear
ofa long sequence of events. Figure 1-8 dehappens in the body as a nutrient deficiency
shows which assessmentmethods can rebody has too little iron-either becauselron
the person's diet (a primary deficiency) or
prson's body doesn't absorb enough, excretes too much, or uses iron
(a secondary deficiency). A dier history provides clues to primarl
e health hisrory providescluesto secondarydeficiencies.
body begins to use up its stores of iron. At this stage, the deficiency
ribed as a subclinical deficiency. It exists as a covert condition, and al_
rbe derectedby laboratory tests, outward signs are not yet apparent.
body's iron stores are exhausted.Now, it cannot make eno,rsh irorri Hood cells to replace those that are aging and dying. Iron iJneeded
ctlls to carry oxygen to all the body's tissues. When iron is lackHood cells are made, the new ones are pale and small. and everv
f feels the effects of oxygen shortage. Now the overt symptoms of
fatigue, pallor, and headaches,reflecting the ironrhe blood. A physical examination will reveal these svmptoms.
of POpulations
Toassess
a popularions
nu-
conduct surveys using techniques similar to those used
The data collected are then used by various agenciesfor numerous
the development of national health goals.
,| The integratedsurveyis caLledWhqtWe Edtin
Anenca.
Surveys The NationalNutrition Monitoringprogramcoorsurveysand researchactiviriesofvarious federal
ol two major national surveys 0 provides comprehensive
One survey collects data on the kinds and amounts offoods people
rchers calculaterhe energyand nurrientsin r he foodsand compare
umed with a standard. The other survey examines the people
antbropometricmeasurements.
physicalexaminations,and Iabdata provide valuable information on severalnutrition-related
:|s growth retardation, heart disease, and nutrient deficiencies.
qll€d the cdrinuins survey ofFood lnrakesby tndividuals(csFrr).
conductedby
iculfue (USDA).
ftc National Heahh and Nurrition Examinarion Survey (NHANES).
overt (oh-VERT)i
out in the openandeasytoobserve.
. ouwir= to open
prlmarydeficiency:a nutrientdeficiency
causedby
inadequate
dietaryintakeofa nutrient,
secondary
deficiency:a nutrientdeficiency
caused
bysomething
otherthananjnadequate
intakesuchas
a disease
conditionordruginteractionthat reduces
absorption,
acceLerates
use,hastens
excretion,
or
destroys
the nutrient.
subcllnlca
I deficiency:a deficiency
in the eartystages,
beforethe outwardsignshaveappeared.
covert(KoH-vert):
hidden,asifundercovers.
. (ouvrit=tocover
23
=
24
(low-income famiNational nutrition surveys otten oversample high-risk groups
and Mexican
lies, pregnant women, a;lolescents,the elderly, African Americans'
status'
ameilcans) to glean an accurate estimate of their health and nutrition
surveys is
nutrition
national
the
from
information
The resultiig wealth of
to
information
this
uses
Congress
For
example,
used for a variely of purposes
the
and
programs'
assistance
food
education,
establish public policy on nutrition
research
,"g.,lutlon of tt " food ,opply. Scientists use the information to establish
relations
public
in
guide
decisions
to
data
these
prtrities. The food induitiy uses
major reports
and product development The Dietary Referencelntakes and other
information
on
depend
health
and
diet
that examine the relationships between
for develbasis
the
provide
also
data
These
collected from these nutritron surveys
goals'
oping and monitoring national health
.E
Surveysprovide valuabteinformation about the
kindsdf foodsPeopleeat.
the nations
National Health Goals Healthy People is a program that identifi'es
disease At
prevent
and
health priorities and guides poliiies that promote health
health
nations
the
improving
the start of each decade,the program sets goals for
nueach
with
areas'
focus
during the following ten year;. Nutrition is one of many
Apand
objectives'
merous objectives.iable-l-5 lists the nutrition and overweight
p;ovides a table of nutrition-related objectiYesfrom other focus areas
pendixJ
'
and overAt mid.-decade,the nations progress toward meeting its nutrition
14
and
in
overweight
Trends
bleak
weight Healthy People goals *^, ,o-"-hut
and
grains
whole
and
obelity *orser,ed. oije.iit es to eat more fruits, vegetables,
"what we
Clearly'
to irr.r"ur" physical activity showed little or no improvement
goals
eat in America; must change if we hope to meet the Healthy People
N a t i o n a l T r e n d s W h a t d o w e e a t i n A m e r i c a a n d h o w"a
h a s i t"c h a n g e d o v e r t h e
lot We eat more meals
past 40 years? The short answer to both questions is
portions W€
n*uy fro- ho-", particularly at fast-food restaurants We eat larger
foods
drink more sweetened.beveragesand eat more energy-dense,nutrient-poor
habits'
dietary
such as candv and chips. We snack frequently As a result of these
TABLE1-5 Healthy People Nutrition
and Overweight Objectives
HealthyPeopte:a nationatpubticheatthinitiative
of Heatth
ofthelJ.SDepartment
underthejurjsdictjon
the most
(DHHS)
thatidertifies
Services
andHuman
threatsto heatthandfocuses
sjgnificantpreventabte
them.
effortstowardetirnjnating
. Increasethe proportionof aduttswhoare
at a healthyweighL
. Reduce
the proportionof adultswho are
obese.
. Reduce
the proportionof childrenand
ot abese.
whoareoverweight
adotescents
. Reduaegtowth tetordolio,?among[owunderage5 Years.
incomechildren
. Increasethe proportionof personsaged2
at leasttwo
yearsandotderwhoconsume
dailyservingsofffuit
. Increasethe proportionof personsaged
at least
2 vearsandolderwhoconsume
with at
thiee dailyservingsof regetdbles,
leastone-thirdbeingdarkgreeoor ofange
vegetables.
. lncreasethe proportionof personsaged2
at leasts]x
vearsandotderwho consume
iaity servingsof gtroinprodurtr,with at
leastthreebeingwhotegrains.
. Increasethe proportionof personsaged2
lessthan
leaG andolderwhoconsume
fdt.
i0 percentof kcaloriesfrcr. sdtututed
. Increasethe proportionof personsaqed2
no morethan
vearsandolderwhoconsume
frcn totalfot
fo percentof kcatories
. Increasethe proportionof personsaqed2
yearsandolderwhocons!me2400mgor
lessol sodium.
. lncreasethe prcportionof personsaged2
yearsandolderwho meetdietaryrecomfor cal6irm.
mendations
. Redtceirondefrciency
amongyoungchilage,and
dren,femalesof childbearing
pregnantfema[es.
pregnant
. Reduce
drerridamong[ow-income
fematesin their third trimester.
and
. Increasethe
proportion
of chitdren
aged6 to 19 yeafswhose
adolescents
intake of neIk ond snacks0t schoolcon'
tributesto goodoveralldietaryquatity.
. Increasethe proportionof worksitesthat
oftet nutition ot weiqhtnanagenent classes
or counseung.
office
. Increase
of physician
the proportion
visjts madeby patientswith a diagnosisof
diabetes,or hyper_
disease.
cardiovascutar
or educafipjdemiathat includecounseling
tion relatedto diet ond nuttition,
. Inctease
food securityamongU's. householdsandin sodoinqreducehunger.
NOTE:"NutritionandOverweighfisoneof2sfocusareaseachwithnumerousobjectivesSeleratoftheotherfocus
added'
in AppendixJ Emphasis
nutritjon retatedobjectives.andthesearepresented
NeatthyPeopte20lo, wwwhealthvPeopte.qov
SOURCE:
---I
25
i![i['::i:-- intake has risen and, consequently,so has
the incidence of overweight
n&: ::i: t'.. Overweightand obesity,in turn, profoundly
influenceour health_as
me rtr ::.tion explains.
,,
r r..i-.:! People become malnourished when they get
too litrle or too
-'':nergy or nutrients. Deficiencies, excesses,and imbalinces
of nutrients
ha: :: Irtalnurrition diseases.To detect malnutrition in
individuals, health_
r:
:i.-'fessionals use a combination of four nutrition assessment
methods.
k-to
mg historical information on diet and health may suggest
a possible
ra-:rn.problem.
Laboratory rests may detecr a possibie nriirltion p.obl"m
r L. -arliest stages,whereas anthropometric measurements
and physical
rlr*ff:nations pick up on the problem only after
it causes symptorirs. National
s-r-'i i use similar assessmentmethods to measure people,s
flod consump_
'
m;-nd
to evaluate the nutrition status ofpopulations.
=
Ilbt and Health
i-urc-.::r a_r'italrole in supporting health.r5 Early nutrition
researchlocused on
MJ.::rg
the nutrients in foods that would prevent such common
diseasesas
crc:ad scurvy, the vitamin D- and vitamin C_deficiency
diseases.With rhis
m,rrt:ge. developed countries have successfully delended
against nutrient defi_
-u:--rase.
h u n g e ra n d n u l r r e n td e h c i e n c vd i r e a s e " s . r j pl ro s ea m a J o r
.\\orid
* r: rieat in developing
countries, however,but notiecause of a lack ofnutrition
(as Chapter 20 explains). More recently, nutrition
m-.-:-ie
researchhas focused
m :h. nic diseasesassociatedwith energy and nut.ient
excesses.Once thoughr to
n :.::- :..untries' problems,,,chronic diseaseshave now
becomeepidemic in devel_
rro! _:unrries as well-contributing to three out of five deaths
worldwide.L6
t::niC
DiSeaSeS
Table t-6 lisrs the ren leading causesof death in the
-m:i Srares.These "causes,,are stated as if a slngle
iondition such as heart
r:*:s' :aused death, but most chronic diseasesarise from
muhiple factors over
iu:
i3rs. A person who died of heart diseasemay have
been overweight,had
rg:- '....d pressure,been a cigarettesmoker,and spentyears
eatinga diet high in
a - - : , J f a ra n dg e l r i n gr o o l i r t l ee x e r c i s e .
l: -:urse, not all peoplewho die ofheart diseasefit this
description,nor do all
p::r.: :, irh thesecharacrerisrics
die of heart disease.peoplewho'are overweight
:-g: :re from the complications of diabetes insteacl, or tirose
who smoke might
n. -:_:;ncer. They might even die fron something
totally unrelated to any of
rr:- :crors such as an automobile accident. Still, siatistical
studies have shown
rr:: _::rain conditions and behaviors are linked to certain
diseases.
'' ;: ie
that TableI-6 highlights four of the top six causeso[ death
as having a
rr. ;rh diet. Since 1970,as knowledge about these diet and
disease
relationships
-.'; -he death rates for three of these_heart disease,cancers,
and strokes_
r--:.::ed.17 Death rates for diabetes-a chronic clisease.tor"ifur"o.iut"arvitt
:-ri-: . -incfeased.
TABT.E
r-6 Leading Causes of
Death in the United States
Per(entageof
Totat0edthg
1. Heartdisease
2. Cancers
3. Strokes
4. Chronic
Iungdiseases
5. Accidents
6. Diabetesmettitus
7, Atzheimertdisease
8. Pneumonia
andinfluenza
9. Kidney
djsea5es
10, Btoodinfections
26.5
22,a
5.9
5.3
4.7
3.1
2.9
2.6
1.8
1.4
N0TF:Thediseases
hiqhtighied
in boldhaverelationshipswith
diet.
S0URCE:
NationatCenterforfeatth5tatistirs,
www.cdc.gov/nchs
J-< Factors for Chronic Diseases Factors
thatincrease
or reduce
-si;
,-o[ developingchronic diseasescan be identified by analyzing
statistical
_:. ,:, strong association between a risk factor and a disease
means that when
-. -:ior is present, the lihelihoodof developing the disease
increases.It does not
.. -- :hat all peoplewith the risk factorwill developthe
disease.Similarly,a lack
:-.i lactorsdoes not guaranteefreedom from a jiven
disease.On the average,
" : ,.1. rhe more
risk factors in a person,slife, the"greater that person,s
chances
:: . eloping the disease. Conversely, the fewer rislifactors in
a person,slile, the
' , .: rhe chances
for good heahh.
:actors Persist Risk factors tend to persist over time.
Wirhout rnterven_
: : \'oung adult with high blood pressurewill most likely
continue to have
chronicdiseasesidjseases
characterjzed
bya slow
progression
andtongduration.
Examples
include
heaft
dlsease,
canceL
anddiabetes.
riskfactor:a condition
or behavior
associated
withan
plevateo
hequencv
ot a disease
butnotproveo
ro oe
,isl fa(to.s,orchronic
causat.
Lead'ng
disedses
i-ctude
obesity,
cjgarette
smoking,
hjghbloodpressure,
high
btoodcholesterol,
physicalinactivjty,
anda djethjghin
saturated
fatsandlowjn vegetabtes,
fruits,andwh;te
grarns,
. 2 5
high blood pressure as an older adult, for example Thus, to minimize the damage,
early interventionis mosl ef{ective.
Risk Factors Cluster Risk factors tend to cluster. For example, a person who is
obese may be physically inactive, have high blood pressure, and have high blood
cholesterol-all risk factors associatedwith heart disease. lntervention that focuses on one risk factor often benefits the others as well. For example, physical
activity can help reduce weight. Physical activity and weight loss will, in turn,
help to lower blood pressure and blood cholesterol.
Risk Factors in Perspective The most prominent factor contributing to death
in the United Statesis tobacco use, I followed closely by diet and activity patterns,
and then alcohol use (seeTable I-7).18Risk factors such as smoking, poor dietary
habits, physical inactivity, and alcohol consumption are personal behaviors that
can be changed. Decisions to not smoke, to eat a well-balanced diet, to engagein
regular physical activity, and to drink alcohol in moderation (if at all) improve
the likelihood that a person will enjoy Sood health Other risk factors, such as
genetics,gender, and age,also play important roles in the development of chronic
diseases,but they cannot be changed. Health recommendations acknowledge the
influence of such factors on the development of disease,but they must focus on
the factors that are changeable. For the two out of three Americans who do not
smoke or drink alcohol excessively,the one choice that can influence long-term
health prospects more than any other is diet.
for oneof every
is responsible
I cjgarettesmoking
fivedeathseachyear.
TABLE1-? FaCtOrSCOntributing
to Deaths in the United States
Fa(tors
Percentage
of Deaths
Tobacco
18
Poordiet/inactivjty
Within the range set by genetics, a person's choice of diet
IN SUMMARY
influences long-term health. Diet has no influence on some diseases hut is
linked closely to others. Personal life choices, such as engaging in physical activity and using tobacco or alcohol, also affect health for the better or worse.
MicrobjaI
agents
Toxicagents
Ilotor vehicles
The next several chapters provide many more details about nutrients and how
they support health. Whenever appropriate, the discussion shows how diet influences each of today's major diseases.Dietary recommendations appear again and
again, as each nutrient's relationships with health are explored. Most people who
follow the recommendations will benefit and can enjoy good health into their
Sexualbehavior
Ilticjt drugs
1
ofdeathin
50!RcE:A,H, 'ilokdadandcoauthots,Actuatcause5
! 'e LnirpdSla es. 2000 tou'4oloJt\e tner.or tte&.olAstotio'
tiah 29I l2Aaq, !Ba-7?45, with cotrectjons from J,,rndl ot f/le
AneticaniledXolAtso.iotion293\200\):293.
later years.
Each chapter in this book ends with simple Nutrition Portfolio activities that invite you to review key messagesand consider whether your personal choices are
meeting the dietary goals introduced in the text By using the information you
are recording in Diet Analysis +, the dietary tracking software that accompanies
this text, and keeping a journal of these Nutdtion Portfolio assignments,you can
examine how your knowledge and behaviors change as you progress in your study
of nutrition.
Your food choices play a key role in keeping you healthy and reducing your risk
of chronic diseases.
After you have recorded at least one day's foods in Diet Analysis +, please look
at that day's choices and record your answers to the following in your journal:
. Identify the factors that most influence your food choices for meals and snacks.
.E
@
Physlcatactivity can be both fun and beneficiat.
. List the chronic diseaserisk factors and conditions (listed in the definition of
risk factors p.25) that you have.
. Describe lifestyle changesyou can make to improve your chances of enjoying
good health.
lej tn:lf6
fLU5f
-
To completet his exercise.go I o your D iet Analysis Plus
al r.rww.cengage.com/sso.
27
tutrition on the Net
=. =-:i .Dw
;ir -,--_='::udy oftopjcscovered
jn this chapter,logonto www.cengage
-rr=O
}:::r
for "nutrition" at the U.S. Government health
i:. rurrition information sites:www.healthfinder.gov
;r! E-rr$.nutrition.gov
-::'i-:-
more about basicscienceresearchfrom the
rnal ScienceFoundation and Research!America:
r.rr.nsf.gov and researchamerica.org
L:-:l
the Dierary Referencelntakes: www.nap.edu
View progresson Healthy People2010and 2020:
www.heahhypeople.gov
Visit the Food and Nurrition secrionof Health Canada:
www.hc-sc.gc.ca
Learn about the national nutrition survey: www.cdc.gov/
nchs/nhanes.htm
Create a chart of your family health history at rhe U.S.
Surgeon General'ssite: familyhistory.hhs.gov
Find credible health inlormation from rhe Cenrers for Disease Control and Prevention: www.cdc.gov/healthyliving
i-:'r:\\ nutrition recommendations from the Food
::- ,l.Ericulture Organization and the World Health
--:::lzation: www.fao.org and www.who.int
Beferences
:
::Der, Nulri!ional implica!ions ofgenetic taste variation: The
-: : : PROP
sensitiviry and other taste phenotypes, Annr.ll Rerielv oJ
, ' : : , ' l 8 ( 2 0 0 8 ) :3 6 7 3 8 8 ; A . A . B a c h m a n o va n d G . K . B e a u c h a m p ,
-. . ::.epror genes,Atlrl dl Rsview oJN rrftionz1 (2007): j\g 4h;
. : :rh€ml and coauthors. Nurrigenomics of taste lmpact on
: :::::ferences and food producrion, Foruln o/Nl|r-trion 60 (2007):
. r l K . K e , l d l o a n d e o a u r h o r , . s a m " B e n e l r c c o m p o n eunnr_s
= . : . .i lffere n t measures of sweet taste pre feret\ce, AmericanJournal
- : i : i n l r - u t r - i t i o n8 6 ( 2 0 0 7 ) : 1 6 6 l - 1 6 6 9 ; M . R . y e o m a n sa n d c o a u : r: Human hedonic responses ro sweerness:Role of raste geneiics
i:: :.-rrorny. Ph]siolog) a d Beha.,,ior9I (2007): 264_27j;A. Knaapila
:: ::rurhors, Food neophobia shorvs heritable varialion in humans,
: ' i: . ,.{_\'dnd Befiavior 91 (2007): 571-578; D. R. Reed, T. Tanaka, and
- - l.lc Daniel. D ivere rastes: G enetics of sli,eer
and bitrer perceprion.
; . j : , - ' . d n d B e h a } i o r g B ( 2 0 0 6 ) :2 1 5 - 2 2 6 .
r=:rier. Hey everyone, dinner's ready . . . two *,eeks ago,Jo'rnal o/
' : -.-1.t ican Dietetic Associdti
on lA7 (2007): 26,)7 .
j:'.rn and coauthors, Food pr€pararion by young aduhs is
associ_
i : : i :rh betrer die! qu ality, I oLtrllctloJthe Al eriajn Dieteti. Associatiotl
lf06): 2001-2007.
- : : r : \ l a r k e t i n g I n s t i r u r e ,w w w f m i . o r g / r e s e a r c h ,a c c e s s e d
Seprember
_ t.'.r8.
- : r-.
::.in of ihe American Dieretic Association: Funcrional foods,Jour. : : ' : l . eA m e r i c d nD i e t e i i cA s s o . i d t i o r 1 0 4 ( 2 0 0 4 ) rB t 4 - 8 2 6 .
- I .- r.rn of rhe American
Dieteric Associarion: Toral dier approach ro
:.-::nicating
{ood and nurrition in formation ,lournal of the Afiericqn
: : : . : i . - { s s o c i a t i o n1 0 7 ( 2 0 0 7 ) . 1 2 2 4 - I ) t .
- - :ran and M- Muller, Nurrigenomics: From molecular nutrition ro
: : .:llion of disease,Jovr nal oJth e Am er ican D ietetic AssociationlA 6
:
: : 569-576;J. Ordovas and V Mooser, Nutrigenomics and nulri:.- !'.'.cs.Currcnt Opinion in Lipid,ologJ1,5Q0A5): 10r-I08.
' r : D{gosrino,Jr. and R. B. DAgostino,
Sr., Esrimating rrearmenr ef_
: r:: u: ing observational d,ata,lournal ol the American MeAicdl Associa_
::197 (2007)r314-316.
lesser and coaurhors, Relaiionship between fundlng source and
: r: usion among nurrition-related scienrifrc articl€s. pLoS M.di.in€ 4
- : : 11001-0006.
:-r1irlee on Dierary Relerence tnrakes. Dietaty ReJerence
Intahes
.'.rrtr. Potassium,Sodinm, Chloride, ana S
Jate (Washingron, D.C.:
National Academies Press. 2005); Commiftee on Dierary Reference
Ifi^kes, Dietary ReJerenceIntd hesJor Eneryj, Carbohldrate, Fiber, Fat,
Fattl A.ids, Choiesterul,Protein, an.l Amino Acids (Washington. D.C_:
National Academies Press, 2005); Commitr€e on Dierart Reference
lntakes, DietdrJ RejerenceIntakesJor Vitdmin A, VitaminK, Arsenic,
Boron, Cbomium, Copper,Ioline, Iron, Ma gd,nese,
MalJbdenun, Niclrcl,
Silicon, vanaaium, and,Zin. (Washingron, D.C.: Narional Academies
Press, 2001); Commitree on Dierary Referencetnrakes, Dierary R4erenceInLaheslor Vitamin C, Vitamin E, Selenium,and Cdr.oreroi,ls(Washington, D-C.: National Academies Press. 2000)t Commirtee on Dierary
Re|rence hrt akes, Diet dr), ReJtren.eIfltdhesJor Thiami!1,Ribo&a.vin,
Niacin. Vital in 86, Folate, Vitamin Bt|. Pantothe ic Atia, Biotin, and
Choline (Washington. D.C.: Narional Academies Pr€ss, 199B); Committee on Dietary ReferenceInrakes. Ditfd,) ReJerekceIntahesJor Calcium,
Phosphotus,Magnesium, Vitamin D, and Fluorias (Washing ton, D.C.:
National Academies Press, 1997).
11. R. M. Russell, Current framework for DRI development: What are the
pros and cons? Nuirition Reriews 66 (2008): 455-458.
r2. C. L. Taylor, Highlights of "a rnodel for establishing upper levels of
intake lbr nr.rtrientsand relared subsiances: R€port ofajoinr FAO/
WHO technical workshop on nurrienr risk assessmenr,May 26, 2005,',
N u t r i t i o n R e l i e 1 r s6 5 ( 2 0 0 7 ) :3 1 - 3 8 .
13. P J. Stoi'er, lnfluence ofhuman genetic variarion on nutritional
requirements, Americdn Journal oJClitical Nurrition B3 (2006):
4365 4425.
14. U.S. Departmen! of Heafth and Human Seri ces, Health) people 20i0
Midcorrse Review (Washington, D.C.: U.S. covernment prinring Office,
D e c e m b e r2 0 0 6 ) .
15. D. R. Jacobs and L. C. Tapsell, Food, no! nutrienrs. is rhe fundamental
unit in nulritlon, Nutrition Reviews65 (2007): 439-450.
16. B. M. Popkin, clobal nurrition dynamicsr The world is shifring rapidly
toward a diet linked with noncommunicable d\sease,American low al
oJClinical Nutrition 84 (2006): 289-298.
17. A.Jemal and coauthors, Trends in the leading causes oI dearh in the
United States, 1970-2002, lanrnal oJthe American Meait:al Associ'.tion
294 (2005): 1)55 1259.
18. A. H. Mokdad and coaurhors, Actual causes of dearh in the Unired
States,2000.Jonndl oJthe A erican Medical Asso.idrio 29l (2004):
r238-1245.
=
28
I_lIGHI_,IGHT
I,{utritton
an
Inforryation
MisinformationOntheNIetand
in theNews
Howcan peoptedjstinguishvaUdnutrition informationfrom mjsjnformation?
is to notjcewhois providing
0ne exce[entapproach
"who"
behjndthe informationis not atways
the jnformation.The
in the wortdof electronicmedia.Keep
evident,though,especiatly
in mind that peopledevelopCDsand DVDSand createwebsites
, s t a s p e o p l ew r i t e b o o k sa n dr e p o r tt h e n e w s .
o n t h e I n t e r n e Lj u
e h e t h etrh e p e r s o ni s
r se e dt o d e t e r m i n w
I n a l [ c a s e sc. o n s u m e n
quatifiedto providenutritionjnformation.
T h i sh i g h t i g hbt e g i n sb y e x a m i n i ntgh e u n i q u ep o t e n t i aaLsw e t l
of retyingon the Internetandthe mediafor nutriasthe probtems
of how to idention information.It continueswith a discussion
tifv retiab[enutrition informationthat apptiesto a[[ resources,
practiceexperjence.
SeeaLso
diefefi.
technician,registered(DTR).
thecase
approved;in
aacredited:
or universities,
of rnedical
centers
by
recognized
certified
byar agency
Department
of Education.
thel.l.S.
dietetictechnician,registered
who
technician
(DTR):a dietetic
examination
haspassed
a national
reqistration
througlr
andmaintains
professionaI
education.
contjnujng
AnericanDieteticAssociation
trainedin
organizatjon dietitian:a person
(ADA):theprofessjonaL
anddiet
foodscience,
States.
The
nutrition,
in the United
of dietitians
js Dietitjans
pLanning.
of
Seealsoregisfered
canadjan
equivatent
simiLarly.
canada,
whichoperates
certified nutdtioni5tsor
DlRt seedietetictechnicion,
celtifi ed nutritionaI consuttanis
registered,
or certified nutrition therapists:
the pronotion,
f raudutent:
a person
whohasbeengranted
gain,of devices,
forfinancial
dec[arjng
hjsor her
a documeft
plans,
oI
5ervrces,
asa nutritionprofessionaL. treatmentS,
authority
products
(inctudjng
dietsand
Seealsonutritiorisf.
thatalterorcLairr
supptementt
a person
dietetictechnician:
without
condition
to attera human
a minjmum
whohascompLeted
proofof safetyor effectiveness.
degreefroman
of anassociate's
lnternet (the Net):a worldwide
and
or coLlege
accredjted
unjversity
network
of mittjons
of computers
dietetjc
technicjan
anapproved
information.
together
to share
tinked
program
thatincludes
a supervjsed
dw-z
gtossaryB
.
accompanying
t n dt h e n e w s (The
i n c l u d i n tgh e ] n t e r n e a
definesretatedterms.)
Nutrition on the Net
Got a question?The Internet hasan answer'The Internet offers
endlessopportunjtiesto obtain high-quatityinformation.but it
or inaccuof incomptete,misteading,
atsodetiversan abundance
pubtish
anything.
rateinformation.lSimptyput: anyonecan
W i t h h u n d r e d so f m i t [ i o n so f w e b s i t e so n t h e W o r l dW i d e
for nutritioninformationcan be an overwheLming
Web,searching
registereddietitian(RD):
a
whohascompleted
a person
from
degr€e
minimum
of a bachelor's
univ€rsity
orcoLlege,
anaccredjted
coursework
approved
hascornpteted
program,
practice
anda supervised
examinatjon,
a national
haspassed
through
registration
maintajns
or rnisteadinq and
faLse
rnisinformation:
professjonai
education.
continuing
information.
registrationrListing;wjth respect
who
nutritionistia person
listing
to heatthprofessionats,
in thestudyof nutritjon.
specialjzes
organization
wjtha professiona[
doesnot
definition
Notethatthis
work,
specific
course
thatrequires
qualificatjons
andrnayappty
specify
of an
andpassing
experience,
but
dietitians
notonlyto registered
examination,
whose
experts
atsoto self-described
websites:Internetresources
14ost
states
trajningjs questionabte.
fites,
of textandglaPhic
composed
define
the
laws
that
haveLjcensing
(Uniform
LJRL
eachwitha unjque
forthosecaLting
scope
of practice
thesite
thatnarnes
Resource
Locator)
nutritionists.
themseives
(forexampte,
www.usda.gov).
pubticheatthdietitians:dietitians
WortdWideWeb(theWeb,
in providing
whospecjalize
www):a
abbreviated
organized commonty
through
nutrjtionservices
graphical
subset
of theInternet.
efforts.
communjty
licenseto practicerpermissjon
[aw,qrarted
understateorfedera[
to use
crjteria,
specifjed
onmeeting
asdietitian)
a certaiftjtte (such
Licensed
andoffercertainservices.
dietitiansmayusethejnitialsLD
aftertheirnames.
RDtseeregistercddietitian.
29
. . : . - m u c h [ i k ew a L k i ni n
g t oa ne n o r m o u s
: L hn : l l i o n so l b o o n s m
, agazines.
Determine Whether a WebsiteIs Reliable
. , - ' . a f d v i d e o sA
. n d l i k ea b o o k s t o r e ,
' - . - : : o f f e r sn o g u a r a n t e e s
of the accu. Why?Whyis the sjte givingyouthis
Todeterninewhethera web: - : ' i f o r m a t i o n f o u n dt h e r e - m u c ho f
siteoffersreliab[enutritioninformation,
information?
Is the site providinga
: --: fictron.
askthe fo[[owjngquestions:
publicserviceor se[[inga product?
. - . - q t h e I n t e r n e t k, e e pi n m j n dt h a t
Manycommerciai
. Who?Whois responsibte
sitesprovideacforthe site?
r : : ,' health-related
informationavai[curate
inforrnation,
but somedo nor.
Is it staffedby quatifiedprofession: : a b r o a dr a n g e .Y o um u s te v a l u a t e
prime
When
money
is
the
motivation,
als?Lookfor the authors'namesand
.
- ' . - i h e j r a c c u r a c yj ,u s t [ i k e e v e r y
be
aware
that
the
information
maybe
credentr'ats.
Haveexpertsrevjewed
-he
the
- -.
a c c o m p a n y i "nHgo wT o "p r o b
i
a
s
e
d
.
contentfor accuracy?
:: ' - leterminjnw
g h e t h ear w e b s i t e
ts
Ifyou aresatjsfiedwith the answers
. When?Whenwasthe site last upto
previous
a[[
questions,
of
the
then
ask
'
dated?Because
nutritionis an ever.
: - : m o s tt r u s t w o r t h ys j t e su s e db y
this finaIquestion:
'
changing
science,
sitesneedto be
. - : o t h e r si s t h e N a t j o n a L
I ibrary
. What?Whatis the message,
datedandupdatedfrequently.
: t b M e d .w h c h p r o v ' d e :f r e ea c andis
-:
it
in
tine
.
with
other
retiabte
sources?
Where?
Where
is the information
. r . 1 0n l l l i o na b s t " a c t(ss n o r r
comlnformationthat contradicts
common
ing fron?Thethreelettersfotlowjng
.
. : i r e s e a r cp
h a p e r sp u b l i s h e idn
jdentjfythe
knowtedge
- - shouldbe questioned.
i\'4any
the dot jn a Webaddress
- ' - e t s a r o u n dt h e w o r t d .M a n ya b provide
reliabie
sites
links
to
other
sjte'saffitiatjon.Addresses
: - ' : L i n k st o w e b s i t e sw h e r ef u t l
ending
"edu"(edu" ' , . .. -'.ableF
sitesto facititateyourquestfor knowtin "gov"(government),
. i g u r eH 1 - 1( p . 3 0 )i n t r o ,
': : -::Leres0urce.
edge,but this provisjonalonedoes
cationaIinstitute),and"org"(orga. = : : ' v e t h e e - m a i Iw a r r ] i n g
n o Lg u a - a n t eaer e p u t a b t e ' n t e r L i o n .
nization)generatty
provjderetiabLe
about
"corn"(commercial)
: - : : : - ? n a s c a u s i n gt h e d i s e a s "en e Beawarethat anysite can[inkto an,
information;
sites
othef
sitewithoutpermission.
represent
- : . : : ' : ' s ' ? I f s o ,y o u ' v be e e ns c a m m e d
businesses
and,depending
. ' : : - ' ' r n f o r m a t i o n .W h e nn u t r i t i o n
on theirquafifications
andintegrity,
, : - : - - ' . e s i n u n s o t i c i t eed- m a i L sb,e
mayor maynot offerdependabte
information.
. , - : . : - d i n g i t t o y o u d i d n ' tw r j t ei t
.
- ' . ' : ' : . C e t e r m i nweh od i d o r i f t h a t
: - _ : 1 U O ne x p e r t .
- - ' . : : : : r , , , a rt dh i s t oe v e r y o n e y o u
"W" questions
Visita nutrjtionwebsiteandanswer
the five
to determjne
whetherit is a retiableresource.
--'s js
- : : -.
n o t a h o a x "a p p e a r s
: : : : - : - : : i a r eg o o d t h a t i t i s .
. ' = : : : - - : ; i i o n a I a n dy o u ' v en e v e h
r e a r da b o u tj t f r o m
- : : : : : __ : a s .
- : : - . - : - ' . . n p h a t i ca n dt h e t e x t i s s p r i n k l ew
dithcapi, : : , . : : - - : e x c L a m a t im
o na r k s .
: t . . - - : . - : - g i v e f o r ,i f p r e s e n ta, r eo f q u e s t i o n a b [ e
- -r
: : : - : : : e e nd e b u n k eodn w e b s i t essu c ha sw w w
mlEc(r:::-. org or urbanlegends.abOUt.com.
Soffiritionin the News
, - r r E - - - - _ : - o f t h e i r n u t r i t i o ni n f o r m a t i o n
fromInteru s r : - r- : - - ' : i o n n e w sa, n dm a g a z i naer t i c l e sw, h j c hh a v e
't:--. . . :-::s of how
d j e t i n f l u e n c etsh e d e v e l o p m e n t
--- ' , - - a : s b e n e f i ft r o m n e w sc o v e r a goef n u t r i t i o n
, ' - + : : - : : - a k e l i f e s t y l ec h a n g etsh a t w i l l i m p r o v e
their
h e a t t hS
. o m e t i m e sh,o w e v e rp,o p u l a r e p o r t sm i s t e a d
consumers
a n d c r e a t ec o n f u s i o nT. h e yo f t e n t e t t a t o p s i d e sd t o r yb a s e do n
a few testjmonjalsjnsteadof presentingthe resultsof research
s t u d i e so r a b a l a n c oe f e x p e r to p i n i o n s .
T i g h td e a d t i n easn d [ i m i t e du n d e r s t a n d i n
g r n e t j m emsa k ej t
so
difficu[tto providea thoroughreport.Hungryfor the latestnews,
the mediaoften report scientificfindingsprematurety-without
b e n e f i to f c a r e f u jI n t e r p r e t a t i o nr .e p i i c a t i o na, n d p e e rr e v i e w .
usual[y,the reportspresentfindingsfrom a singte,recenttyreleasedstudy,makifg the newscurrentand controversial.
Consequently.the publicrecejvesdiet and heatthnewsquick[y,but not
alwaysin perspective.
Reportersrnaytwr'stinconclusive
findinqs
i n t o " m e a n i n g f udI j s c o v e f j e sw" h e n p r e s s u r etdo w r j t e c a t c h y
h e a d t i n easn ds e n s a t i o nsatIo r i e s .
A s a r e s u t t ". s u r p r i s i nnge wf i n d i n g ss" e e mt o c o n t r a d i cot r e
a f o t h e r ,a n d c o n s u m e rf e
s e l f r u s t r a t e da n d b e t r a y e dO. c c a s i o n a[[y,the reportsare downrightfa[se,but moreoften the apparent
c o n t r a d j c t i o nasr e s i m p t yt h e n o r m a Ir e s u l to f s c i e n c ea t w o r k .
A s i n g l es t u d yc o n t r i b u t etso t h e b j g p i c t u r e b
, u t w h e nv i e w e d
e, it can easjly distort the image. To be
the conc[usions
of anystudymust
meaningfu[,
withinthe contextof
cautiously
be presented
findings.
otherresearch
Identifying Nutrition
Experts
Internet Resource
FIGURE
H1.1 PUBMED(vvvvw.pubmed.gov):
for Scientific Nutdtion References
PubMedwebsiteofferstutoriatsto helpteach
The U.s. NationatLibraryof Medicine's
beginnersto usethe searchsystemeffectivety.often, simpl.yvisiting the site, typing a
"Go"wittyietdsatisfactory
results.
queryin the "Search
for" box,andclicking
"calcium
catciumandboneheatth,typing
concerning
Forexample,
to find research
bone"nets morethan 30,000results.Try setting timits on dates,types of artictes,[anto peruse.
numberof abstracts
guages,
andothercriteriato obtaina moremanageable
of whetherthe mediumis electronic,
RegardLess
print, or video,consumers
needto askwhether
person
is qualified Typesearch
the
information
behind
the
If
the
creator
of an In- termshere
to speakon nutrition.
pineeating
three
website
recommends
ternet
gym
weight,
a
trainer
at
the
a
day
to
lose
apples
praisesa high-proteindiet, or a heaLth-store
clerk suggestsan herbaIsupplement,shou[d Reflne
the
you believethese people?Canyou distinguish searchby
betweenaccuratenews reports and infomer- settinglimits
cialson television?Haveyou noticedthat many
are presentedby Usetutorlal
tetevisednutrition messages
to
resources
food edi- answer
cetebritjes,athletes,psychologists,
tors, and chefs-that is, a[mostanyoneexcept questions
a dietitian? Whenyou are confusedor need
sounddietaryadvice,whomshouldyou ask?
Phvsiciansand Other
He-alth-careProfessionals
$
ddrh
g
f i :: A4lFlll
t
ftLl
g
Bft
",ii{Hm
. Enter one or more *dch lerns. or cli.t I'!tr!t!t!!!lr\
for
. Ente! .r rhL,r![ Li\ as smilhjc. Inhiah e optional
. Enlertl tlLiLrrr j! in full or asMEDLINE
Use theli,Lt x \ l).txb.LJ.to lind jounal titles
abb.eviadons.
to devetopdiet plans
Few,however,havethe time or experience
and provide detaiteddiet instructionsfor clients. Often they
wisely refer clients to a quatifiednutrition expert-a registered
dietitian (RD).
professjonpeopleturn to physicians
or otherhealth-care
i\.4any
to
know
about
aL[heatthexpecting
them
atsfor dietaryadvice,
accurate
and
of
relatedmatters.But aretheythe bestsources
necesbackground
percent
dietitian(RD)hasthe educationaI
30
of
al[
A registered
on nutrition?0nly about
currentinformation
To
become
an
and
care.l
advice
retiable
nutrition
sary
to
deliver
to takea
in the UnitedStatesrequirestudents
medicalschools
about
requiring
person
degree
an
undergraduate
must
earn
25
RD,a
lessthanhalfrequire
the minimum
nutritioncourse;
separate
andotherrelatedsubAcad60 credithoursin nutrition,foodscience,
recommended
bythe Nationat
hoursof nutritioninstruction
pass
jects;
year's
internship
or
the equivaLenU
clinical
complete
a
reading
this
text
moststudents
Bycomparison,
emyof Sciences.2
maintain
upthe
ADA;
and
by
examination
administered
provides
hours
a
national
an average
of 45
aretakinga nutritionctassthat
participating
in
required
by
and
registration
knowledge
to-date
of instruction.
taking
seminars,
suchasattending
activities
(ADA)asserts
continuing
education
that stanTheAmericanDieteticAssociation
research.
conducting
courses,
or
in the curricula
shoutdbe inctuded
dardized
nutritioneducation
physician's
physicians,
Somestatesaltowanyoneto usethe title djetitianor nuprofessionats:
nurses,
for a[[ health-care
physicat
theratritionist, but othersaltowontyan RDor peoptewith specified
andoccupationaI
dentaIhygienists,
assistants,
dietitians.Manystatesprovide
qualifications
provide
to cat[themselves
directly
pists.socialworkers,
services
anda[[otherswho
or [icense
certification,
guarantee:
state
registration,
a
professionats
relevance
of
a
further
understand
the
to c[ients.Whenthese
people
havemet
who
practice.
identjfy
In
this
way,
states
prevention
andhave
to
of diseases
nutritionin the treatmentand
these
state
StiL[,
and
experience.
peopte
of
education
minimal
standards
then atl the
command
of reliablenutritioninformation,
Simitarty,
some
an
RD.
those
defining
may
falL
short
of
standards
theyservewi[[atsobebetterinformed.
graduates
quatify
as
certiprograms
their
educationaI
professionals
bealternative
appreciate
the connections
iqosthealth-care
in ctinified nutritionists,certifiednutritionaIconsultants,or certified
tweenhealthandnutrition.Thosewhohavespeciatized
but [ack
that soundauthoritative
nutrition theraDists-terms
on the subject.
wet[quatified
to speak
caInutritionareespeciatty
RegisteredDietitian (RD)
emptoyees
do not haveextensive
forma|'training
in nutrition,and
theirabitityto provide
accurate
information
mavbe[imited.
Identifying Fake
Credentials
.
o
his rnembershipcertificate to an associationof
coosultants.
His humancompanion.
ConnieDiekman,is
dietitianand past presidentof the AnericanDietetic
::ls of an RD.In fact, even Eddie,an Enqtishcocker
ra: abteto obtain a certjficateof membership
from the
*5Dciation of NutritionatConsultants.a
Derforma multitudeof dutiesin manvsettinosin
"r-ities.Theyworkin the food industry,pharmaceutj. hornehea[thagencies,
tong-termcareinstitutions,
ce,pubtichealthdepartments,
research
centers,
edu-
-qs, fitnesscenters,
and hospitats.Depending
on thejr
. dietitianscanassumea numberof differentjobreandpositions.In hospitals,administratjve
dietitians
tbE =oodservice
system;clinicatdietitiansprovidectient
-L:r'ition support
team djetitianscoordinatenutritjon
c!:er health-care
professionats.
In the food industrv.di_
,:Jct research,
developproducts,and marketservices.
dietitianswhoworkin government-funoeo
aqenc'r rotein detiveringnutritjonservjces
to Deoplein the
linong their manyroles,publichealthdietitianshetp
:--iie, and evaluatefood assistance
programs;act as
= otheragencies;
managefinances;
ano mucnmore.
c Technician,
ered(DTR)
fu|=--:ies,a dietetic technician assistsreqistereddieti:Jrninistrative
andctinicaIresponsibilities.
A dietetic
-es beeneducated
andtrainedto workunderthe guid_
-c:-:tereddietitian;
upon passinga nationalexaminatiL: ihangesto dietetic technician, registered (DTR).
DietaryEmployees
:: rhe dietetictechnician,otherdietaryemptoyees
rnay
. aides,cooks,porters,and assistants.
Thesedietary
In contrastto registereddietitjans,thousandsof peopteobtain
fake nutrition degreesand ctaimto be nutrjtion consuttantsor
doctorsof "nutrimedicine."
Theseand othersuchtittes maysound
meaningfu[,but most of these peopletackthe estabtishedcredentiatsand trainingof an ADA-sanctioned
dietitian.If you took
ctose[y,
you canseesignsof their fakeexpertise,
C o n s j d eerd u c a t i o n abla c k g r o u n fdo, r e x a m p L e
T.h e m i n j m u m
standards
of educationfor a dietitianspecifya bache[or
of science
(BS)degreein food scienceand humannutrition or retatedfietds
from an accreditedcotlegeor university.*Sucha degreegeneratty
requires4 to 5 yearsof study. Simitarty,minimumstandardsof
educationfor a dietetictechnicianspecifyan associate,s
degree
that typicattyrequires2 yearsof study.In contrast,a fake nutrition expert may disptaya degreefrom a 6-monthcourse.such
a degreesimplyfatls short. In somecases,businesses
posinqas
schoolsoffer eventess-they settcertificatesto anyonewho fays
the fees.To obtainthese"degrees,"
a candidateneednot attend
anyclasses,readanybooks,or passanyexaminations.
To safeguard
quality,an accreditingagencyrecogeducationaI
nizedby the u.5. Department
(D0E)certifiesthat cerof Education
tain schoo|,s
meetcriteriaestabtished
to ensurethat an institution
providescompleteandaccurateschooting.
lJnfortunately,
fakenutrition degreesare availablefrom schoo[s"accredited,,by
phony
accrediting
agencies.
Acquiringfalsecredentjats
is especialty
easy
today,with fraudutentbusinesses
operatjngvia the Internet.
Knowjngthe quatifications
of someonewho providesnutrjtion
informationcan helpyou determjnewhetherthat person,s
advice
mightbe harmfu|'
or hetpfu[.Don'tbe afraidto askfor credentiats.
TabteH1-1lists credibtesourcesof nutritioninformation.
Red Flags of Nutrition
Ouackery
FigureH1-2featureseight red flagsconsumers
canuseto identify
nutritionmisinformation.Salesof unprovenand dangerous
products haveatwaysbeena concern,but the Internet now provides
merchants
with an easyand inexpensive
wayto reachmjttionsof
customers
aroundthe wor[d.Because
of the difficuLty
in regutating
the Internet,fraudutentandilLegat
satesof medicalproductshave
hit a bonanza.
As is the casewith the air, no one ownsthe Internet, andsimilarly,no one hascontroIoverthe pollutjon.Countries
. T o e r s u r et h e q u a L i t y
n ft i u t d t j o n a n dd j e t e t i c se d u a n dc o n t i n u ejdm p r o v e m e o
c a t r 0 np r o g r a m sa,n A D Aa g e n c yk r o w na s t h e C o n m j s s i oon, rA c c r e d i t a t i of o
nf
DietetjcsEducation(CAD[)estabLjshes
and enforceseLjgjbitjtyrequjrements
and
d c ( r e d r t aol 1 5 t a n d ad \ f o - o , o g r a mp5- e D a r l Ss t L o e n r .t o . c d . e e r .s . . e g T t e r e d
d i e t i r i a l so d i e t e r i .t F . l - r i c i a l s o
. o q - a f f r F F t i . gt h o . e . t a - d a r dd
. F rccredired
bv cADE.
32
HIGHI_,IGFIT
TABLEHl"1 Credible Sources of Nutrition Information
with reliablehealthand nutritior
provideconsumers
organizations
groups,andprofessional
consumer
assocratrons,
votunteer
agencies,
Government
inctude:
inforrnation
nutrition
of
sources
ClredibLe
information.
or cornmunity
at a university
. Nutritionandfoodscience
departrnents
college
Coopefative
or County
. LocaLagencies
suchasthe heatthdepartment
Service
Extension
. Governrnent
suchasr
heatthagencies
www.usda'gov
. Department
(U5DA)
of Agricutture
www.os'dhhs'gov
. Department
of HeatthandHuman
(DHN5)
Services
(FDA) www'fda.gov
. FoodandDrugAdministration
www.hc-sc.gc.ca/nutrition
. HeatthCanada
. Votunteer
suchas:
agencies
heaLth
www.cancef.org
. American
Society
cancer
www.diabetes.org
. AmericarDiabetes
Association
www,americanheart'org
. American
HeartAssociation
grouPs
suchas:
consumer
Reputabte
ard Health
. American
on Science
Council
. Federal
lnfornationCenter
Citizen
. lnternationat
Council
Foodlnforrnation
suchas:
heatthorganizatjons
ProfessionaI
. American
DieteticAssociation
. American
f4edicaLAssociation
. Dietitians
of Canada
sucha5:
Journals
. Americ1n
Nutritijn
Joumolaf ClinicaL
. JournaL
of theAneticanDietetic
. NewEngland
Journalaf Medicine
. NuttitionReviews
www.acsn.or9
www.puebto.gsa'gov
www.ifa.org
www.eatright,org
www.ama-a55n.ofg
www.dietitians.ca
www.alcn.org
www.adajournat.org
www.nejm.olg
www.itsi.otg
I rrcunn nr-z Red Flags of Nutdtion Ouackery
Satislaction
guaranteed
Marketersmay maKe
generouspromlses,tllll
consumerswonl 0e
ab e to collecton them.
Natural
Naturalis not
better
necessarily
or safer;any
productthatls
strongenough
to be elfectivels
strongenough
lo cause
sideeflects.
One product
does it all
No one productcan posslbly
treat such a diverse array ol
conditions.
ffi
fir
Time lested
Suchfindlngswouldbe widelY
publlcizedand accePtedbY
s.
heath professlona
Paranoid
accusations
And this products
company doesn't
want money?
At least the drug
company has
scientificresearch
proving the sately
and elfectiveness
of its products.
,v!::
w
i;"
Personal
testlmonials
is the
Heafsay
weakestlorrnol
evioence,
Meaningless
medicaliargon
Phonyterms rrlde
the lackof sclentiflc
proof.
33
. . : ---:ri Lawsregarding
salesof drugs,dietarysupplements,
,
: - : - : a l t h p r o d u c t sb,u t a p p t y j ntgh e s el a w st o t h e ] n t e r n e t
. : : : : : 1 sa l m o s it m p o s s i b t eE.v e ni f i t t e g aal c t i v j t j e sc o u t d
- : = ' . : : r d j d e n t j f i e df i,n d i n g t h ep e r s o nr e s p o n s i b t e f opr a r ::- j
:::':e is not atwayspossibte.
Websites
canopenandctose
- = : - . : ' : c u r s o rN. o w ,
n l o r et h a ne v e r c, o n s u m e m
r su s th e e d
'=:,
- 3 u y eb
r eware."
I n s u m m a r yw, h e ny o u h e a rn u t r i t i o nn e w s ,c o n s j d eirt s s o u r c e .
A s ky o u r s e [tfh e s et w o q u e s t i o n s] :s t h e p e r s o np r o v i d i n gt h e
jnformation
q u a t i f i e tdo s p e a ko n n u t r i t i o n ?i s t h e i n f o r m a t i o n
basedon valid scientificresearch?
if not, find a better source.
After att,your heaithdependson it.
ffiutritionon the Net
:: ..::
: ' : o p i c s c o v e r e di n t h i s H i g h t i g h t t, o g o n t o w w w . c e n g a g e
I
. - r : : - : ' , : : : o n aC
o u n cA
i t g a j n sH
t e a l t hF r a u d :
rr.-:a hf.org
- : - ' : : : . , e r e dd i e t i t i a ni n y o u ra r e af r o mt h e A m e r j c a n
:i:-:' - r. ! cciation:www.eatright.org
-
- : - : : - - : ' ' : ; c n p r o f e s s i o ni a
n lC a n a dfar o mt h e D i e t i t i a nosf
=-r:::,tivw.dietitians.ca
- : - r : - : - : t r e r a c o r r e s p o n d e ns c eh o ojIs a c c r e d j t ef d
rom
f : , E: - - . - : : : d u c a t i o n a n dT r a i n i nC
g o u n c iw
[:ww,detc.org
- an: --'
:-! retiableheaithinformationfrom the Heatth
: ww.hon.ch
! r : - n : : : : . l r d a t i o nw
F i n do u t w h e t h ear s c h o o1t sp r o p e r layc c r e d i t ef d
ora
dieteticsdegreefrom the AmericanDieteticAssociation:
www.eatright.org/cade
jnstitutions,professiona[[y
0btaina tistingof accredjted
accreditedprograms.
and candjdates
for accredjtation
from
t h e A m e r i c aC
n o u n co
i In E d u c a t i o w
n :w w . a c e n e t . e d u
Learnmoreaboutquackery
from StephenBarrett'sQuackwatch:www.quackwatch.org
C h e co
k u t h e a L t h - r e l a theoda x e as n du r b a nl e g e n d sw: w w
.snopes.com,
www.scambusters.org,
and urbantegends
.about.com
FindreIabteresearch
artictes:www.pubmed.gov
Erences
lrisi-: _ :' = r -:ricar DieteticAssociationi
Foodandnutrition
--.: - _ ,.,mal of theAmetican
nllr6|s_---:
DieteticAssociatian
106 lZA06)i
l l , . ' i- : : _ : .
: . : u t h o r s , S t a t u snouf t r i t i o n e d u c a t i o rnni n
edicat
- -:' :_ - ,:rrrraLaJClinic1L
dmmmmmmmm
Nutrition83 (2oa6\ 9415-9445.
. o!wi::-:_: = r-:iican DietetjcAssociation:
Therotesof registered
irM:=-: : - : :'=:::jc iechnjcians,
registered
promotion
in heaLth
and
diseaseprevention,Jorrnalaf the American
DieteticAssociation
106
(2006):1875-1884.
Who's
djshjngoutyournutrjtjonadvice?
Consumers
beware:
14ake
sureyourso!rcejs a registered
dietjtian,www.eatright.org,
for retease
lvlarch
3,2008.