Download Ch08 lecture hea02

Chapter 8
Nutrition:
Eating for Optimum
Health
PowerPoint® Lecture Slide Presentation
prepared by
Michael Hall
Copyright © 2008 Pearson Education, Inc.,
publishing as Pearson Benjamin Cummings
Objectives
 Examine the factors that influence dietary choices.
 Discuss how to change old eating habits, including how to use
MyPyramid.
 Summarize the major essential nutrients.
 Discuss food as a form of medicine and the facts related to
new trends in nutrition.
 Distinguish among the various forms of vegetarianism.
 Discuss issues surrounding gender, exercise, and nutrition.
 Discuss how unique situations in your life can influence
dietary needs.
 Discuss the unique problems college students face when trying
to eat healthy foods.
 Explain food safety concerns facing Americans and people in
other regions of the world.
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Assessing Eating Behaviors
 Hunger – lack or shortage of basic foods needed to
provide the energy and nutrients that supports health
 Appetite – a learned desire to eat that may or may not
have anything to do with feeling hungry
• We eat for many reasons that have nothing to do
with being hungry.
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Eating Influences
Cultural and social meanings
attached to food
Emotional comfort
Convenience
Social interaction
Habit or custom
Advertising
Availability
Economy
Weight/body image
Regional/seasonal trends
Nutritional value
Environmental conditions
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Eating For Health
 Nutrition – the science that investigates the
relationship between physiological function and the
essential elements of the foods we eat
 Nutrients – the constituents of food that sustain
humans physiologically: proteins, carbohydrates, fats,
vitamins, minerals and water.
 Calorie – a unit of measurement that indicates the
amount of energy obtained from a particular food
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Eating For Health
 Nutrients and calories from:
• Proteins
• Fats
• Carbohydrates
 Vitamins
 Minerals
 Water
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Eating For Health
 Adequate: provides enough energy, nutrients and fiber
to maintain health
 Moderate: portion control, awareness of the amount of
nutrients
 Balanced: proper combinations of food groups
 Varied: different colors mean you’re getting better
coverage of vitamins and minerals
• Americans typically get 38% of their calories from
fat, 15% from proteins, 22% from complex
carbohydrates and 24% from simple sugars.
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Estimated Daily Calorie Needs, by Age
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Table 8.1
Trends in Caloric Intake
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Figure 8.1a
Trends in Caloric Intake (continued)
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Figure 8.1b
The Digestive Process
 Digestive process – the process by which foods are
broken down and either nutrients are absorbed or
unused portions excreted by the body
 Saliva – aids in chewing and swallowing, contains
enzymes that begin CHO breakdown
 Stomach – digestive organ that mixes food with
enzymes and acids, protein breakdown begins
 Small intestine – digests and absorbs nutrients
 Liver major organ that determines whether nutrients
are stored, sent to cells or organs, or excreted
 Large intestine reabsorbs salts and water and sends
remaining waste along tract
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The Digestive Process
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Figure 8.2
Obtaining Essential Nutrients
 Water
• Can survive longer w/o food than water
• Dehydration can occur in a few hours
• Body is 50-60% water
• Aids in fluid and electrolyte balance
• Transports molecules and cells throughout body
• Major component of blood
• Carries oxygen and nutrients to tissues
• Removes metabolic waste
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Proteins
 Proteins are major component of every cell
 Are made up of amino acids and have 4 calories/gram
 There are 9 essential amino acids the body doesn’t
make and must be obtained from diet
 The other 11 are produced naturally by the body
 Complete protein foods contain the 9 essential amino
acids. Typically animal products contain complete
protein
 Food from plant sources are typically incomplete;
however is it possible to use a combination of plant
sources to obtain all 9 essential amino acids
 Americans rarely suffer from protein deficiency
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Complementary Proteins
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Figure 8.3
Calculating Your Protein RDA
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Figure 8.4
Carbohydrates (CHO)
 Supply us with energy to sustain daily activity
 Carry 4 calories/gram, quicker, effecient metabolism
 2 major types of CHO
• Simple Sugars
• glucose, fructose (monosaccharides)
• sucrose, lactose, galactose (disaccharides)
• Complex CHO (polysaccharides) are found in
grains, cereals, certain vegetables, beans and
potatoes
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Carbohydrates and Fiber
 Complex Sugars: 2 major forms
• starches: breads, pastas, rice, potatoes store as
glycogen
• Fiber or cellulose
 Fiber – the indigestible portion of plant foods that
helps move foods through the digestive system plays an important role in good nutrition
 Most Americans do not get the recommended daily
amount of 20-35 grams
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Fiber
 Insoluble fiber – associated w/ GI benefits and lower
risk for some cancers. Found in bran, whole-grain
breads and cereal, and most fruits and vegetables.
 Soluble fiber – factor in reducing cardiovascular
heart disease by lowering blood cholesterol levels.
Found in oat bran, dried beans, and some fruits and
vegetables
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Fiber Benefits
 Protection against colon and rectal cancer
 Protection against breast cancer
 Protection against constipation
 Protection against diverticulosis
 Protection against heart disease
 Protection against diabetes
 Protection against obesity
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Increasing Fiber
 Aim for 20-35 grams/day
 Select whole-grain breads (not just whole wheat)
 Choose bread w/ 3 or more grams fiber/serving
 Eat fruit and vegetable skins
 Choose fruit over fruit juices
 Sprinkle ground flaxseed on cereals and baked goods
 Use whole-grain pastas, crackers, cookies, etc
 Limit consumption of highly refined white flour
products
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Fats
 Fats (lipids) – vital role in maintaining health skin and hair,
insulating body organs against shock, maintaining body
temperature, and promoting health cell function
• They contain 9 calories/gram
• They make foods taste better
• Carry fat soluble vitamins A,D,E,K
• Provide concentrated form of energy in the absence of
CHO
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FATS
 Triglycerides – most common form of fat circulating in the
blood (95 percent of body fat). The liver converts excess
calories into triglycerides
 Cholesterol – the remaining 5 percent of body fat, can
accumulate on the inner walls of arteries. Is a component of all
cell membranes and is a necessary part of our diet.
• Plaque – the build up of cholesterol; major cause of
atherosclerosis
 HDL: high density lipoproteins, transport circulating
cholesterol to the liver. High HDL “good cholesterol”
levels are desirable; increased w/ regular aerobic exer.
 LDL: low density lipoproteins, play a role in clogging
arteries. Lower LDL levels are desirable to reduce the
risk of heart disease. “Bad cholesterol”
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FATS
 Fat cells consist of chains of carbon and hydrogen
 Saturated fats are unable to hold any more hydrogen
• They generally come from animal sources like
meats and diary products
• They are solid at room temperature
 Unsaturated fats have room for additional hydrogen
atoms in their chemical structure
• They come from plant and vegetable oils
• They are generally liquid at room temperature
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PUFAs and MUFAs
 MUFAs, monounsaturated fatty acids and PUFAs,
polyunsaturated fatty acids, refer to the number of
hydrogen atoms that are missing from their chemical
structure.
 MUFA: preferred fats due to possible lowering of
LDL levels. Examples include olive and peanut oils
 PUFA: less desirable than MUFA, associated with
lowering levels of HDL. Examples include corn,
safflower and sunflower.
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Trans-fatty Acids
 Trans-fatty acids – fatty acids that are produced when
polyunsaturated oils are hydrogenated to make them
more solid and extend shelf life.
 They are known to:
• Raises LDL and lower HDL
• Increase risk of heart disease
• Increase risk of certain types of cancer
• New FDA rules require labels to tell consumers
how much trans fat is the food but only for amounts
greater than 500mg. If a product claims to be transfat free it just has less than 500mg…
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Percentages of Saturated, Polyunsaturated and
Monounsaturated Fats in Common Vegetable Oils
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Figure 8.5
Essential Fatty Acids
 Linoleic acid and alpha-linolenic acids are 2 fats that
are needed to make hormone like compounds that
control immune function, pain perception and
inflammation.
 Linoleic acid: part of the omega-6 family of fats.
Found in soybeans, peanuts, corn and sunflower
seeds. Helps reduce LDL levels.
 Alpha-linolenic acids: part of the omega-3 family of
fats. Found in flax, canola, sardines, green leafy
vegetables, walnuts, salmon and tuna.
 Americans eat far more omega-6 fats
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Choosing Good Fats In Your Diet
 Read food labels
 Pick MUFA/PUFA w/ least amount of calories
 Use olive oil, peanut oil, canola oil
 Eat fish high in Omega 3’s
 Choose lean meats
 Add walnuts and flaxseeds
 Select low fat dairy products
 Limit processed and convenience foods
 Eat fatty fish twice weekly
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Vitamins
 Vitamins – essential, organic compounds that promote
growth and help maintain life and health
• Convert food energy to body energy
• Age, heat can destroy vitamins in foods
 Fat soluble – are absorbed through the intestinal tract
with the help of fats (vitamins A, D, E, and K)
• Tend to be stored in the body and toxic levels can
accumulate in the liver
 Water soluble – easily dissolved with water (B
complex and vitamin C)
• Are easily excreted and cause few toxicity problems
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Minerals
 Minerals are inorganic, indestructible elements that
aid physiological processes w/in body
• w/o minerals body can not absorb vitamins
 Macrominerals: needed in fairly large amounts:
sodium, calcium, phosphorous, magnesium,
potassium, sulfur and chloride
 Trace minerals: needed in small amounts: iron, zinc,
manganese, copper and iodine
 See Table 8.4 on pg 258 for a guide to minerals.
Problems can occur with deficient and excessive
levels.
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A Closer Look at Sodium
 Sodium: daily recommendation is for 1,100 – 2,300
mg/day
• Average American consumes > 4000 mg/day
• There is a controversial link btwn sodium intake
and hypertension.
• High sodium intake may increase calcium loss in
urine increasing risk of osteoporosis
• Majority of sodium in diet comes from processed
foods and is used to enhance flavor and for
preservation
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A Closer Look at Calcium
 Calcium: plays a role in building strong bones and
teeth, muscle contraction, blood clotting, nerve
impulse transmission, regulating heartbeat and fluid
balance in cells.
 Recommended intake is 1,200mg for most adults.
 Vitamin D improves absorption of Ca. Sunlight helps
manufacture Vitamin D.
 Good sources of green leafy vegetables that contain
Ca include broccoli, pinto beans and soybeans
 Carbonated beverages contain phosphoric acid which
increases Ca excretion (Ca is pulled out from bones)
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A Closer Look at Iron
 Iron is found in every living cell of all living things
• Women 18-50 years old need about 18 mg/day
• Men of same age range need about 10mg/day
• Iron deficiency can produce anemia, which is the
inability to produce hemoglobin
• Iron deficient person feels tired and run down and
women are at higher risk. Why?
• Hemochromatosis is iron toxicity due to ingesting
too many iron-containing supplements. Symptoms
include vomiting, diarrhea, rapid heartbeat, weak
pulse, shock and confusion. Can be fatal especially
in children.
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Determining Your Nutritional Needs
 Recommended Dietary Allowances (RDAs):
guidelines for the recommended average daily intakes
of energy and nutrients considered adequate to meet
the needs of most healthy people in the US
 Dietary Reference Intake (DRI): newer version of the
RDA. A set of nutritional values including more than
26 essential vitamins and minerals; applies to healthy
people.
 DRIs are considered the umbrella guidelines under
which the following categories fall:
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Dietary Reference Intakes
 U.S. Recommended Allowances (USRDAs):
reference standard for intake levels necessary to meet
the nutritional needs of 97-98% of healthy individuals
 Adequate Intake (AI): the recommended average daily
intake level of a nutrient by healthy people when there
is not enough research to determine the full RDA.
 Tolerable Upper Intake Level (UL): the highest
amount of a nutrient an individual can consume daily
without the risk of adverse health effects.
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Reading Labels for Health
 Reference Daily Intakes (RDIs): recommended
amounts of 19 vitamins and minerals (micronutrients)
 Daily Reference Values (DRVs): recommended
amounts for macronutrients like total fat, saturated fat,
cholesterol, total carbohydrates, dietary fiber, sodium,
potassium and protein.
 Together the RDIs and DRVs make up the Daily
Values (DVs) that you read on food and supplement
labels listed as a percentage (% DV)
• also includes info on serving size, calories, calories
from fat/serving and percentage of trans fats.
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Reading a Food Label
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Figure 8.6
The MyPyramid Plan
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Figure 8.7