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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.