Dr. David L. Gee
FCSN 245
Basic Nutrition

 Biologically :
– proteins are the most important molecues in the body

“action molecues”
 Nutritionally : (at least in the US)
– proteins are of the least concern for macronutrients in the diet
 protein deficiency very unusual
 excess protein generally not a problem

©2001 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning
™ is a trademark used herein under license.

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©2001 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning
™ is a trademark used herein under license.

©2001 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning
™ is a trademark used herein under license.

©2001 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning
™ is a trademark used herein under license.

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20 different amino acids
– Differ by type of side chain
Water soluble AA
– charged side groups
 Can form ionic bonds
– sulfer containing side groups
 Can form disulfide bonds
Fat soluble AA
– Fat soluble AA interact/dissolve with each other
These interaction/bonds between AA side chains cause proteins to form specific shapes

Protein Structure
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 Tertiary Structure
– folding of coil
– 3-dimensional structure
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Determined by AA sequence
Specificity of a protein’s function
 Diversity of protein functions

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9 “Essential” amino acids
– Amino acids that cannot be made and must be consumed in the diet (dietary essential)
 peptide bonds link amino acids together
 proteins typically contain a few hundred amino acids
– infinite combinations of amino acids
– tremendous diversity of protein types

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DNA, genes, chromosomes
– where the information is stored
“Transcription”
– making a copy of the information
– messenger RNA

“Translation”
– reading the information and making the protein

©2001 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning
™ is a trademark used herein under license.

©2001 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning
™ is a trademark used herein under license.

errors in the stored information
 Examples:
– Sickle Cell Anemia
– Cystic Fibrosis
– Familial Hypercholesterolemia
 LDL-receptor
 Human Genome Project
– Map the genome
 20-25,000 genes in human genome (10/04)
– Fix the genes ???

Have you eaten GM foods?
Are GM foods safe?
 2003 survey of US consumers
– Non-partisan Pew Initiative on Food and Biotechnology
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48 % opposed to GM foods, 25% in favor
– 2001 58% opposed to GM foods
24% say they’ve eaten GM foods
– 58% say they haven’t

Genetic Modified Crops:
Prevalence
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In 2003 (USDA) genetically modified crops accounted for:
– 40% of all corn
– 81% of soybeans
– 73% of cotton
In 2002
– 35% of corn
– 55% of soybeans
Grocery Manufactures of America (2003)
– 70-80% of processed foods contain GMO
USDA approval for
– potatoes, tomatoes, melons, beets
– nicotine free tobacco

Food and Health Issues
 Traditional animal and plant breeding
 Alteration of genetic material with tools of biotechnology
 Advantages:
– speed
– more specific, less random
– interspecies gene transfer

Benefits of Genetically
Engineered Foods
 Reduce use of pesticides
 Bacillus thuringiensis (Bt)
– “natural” pesticide used by organic farmers
– Bt produces a protein toxic to insect larvae
 Gene for Bt toxin incorporated into corn, etc.
– Corn plant produces Bt protein toxin

Benefits of Genetically
Engineered Foods
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Reduce erosion of topsoil due to tilling
– tilling for weed control
Monsanto’s “Roundup” (glyphosate)
– inhibits plant’s ability to make tryptophan
– tryptophan is an EAA for humans
 Roundup resistant plants (soybeans)
– spliced bacterial gene into plant that is resistant to effect of Roundup (still able to make tryptophan)

Benefits of Genetically
Engineered Foods
 Improved nutritional quality of plants
– “golden rice”
 rice with B-carotene gene
– improved protein quality & quantity
– higher in vitamins
 Improved sensory properties
– Tomato and strawberry flavor & texture

Genetically Engineered Foods:
Environmental Concerns
 Pesticide resistant insects
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Unintentional environmental effects
– monarch butterfly larvae - lab study
– affect beneficial insects (ladybugs)
– development of “superweeds”, “superbugs”
Control of Food Production
– Terminator gene
 GMO plants with gene to produce sterile seeds
– Biotech firms with too much control?

Genetically Engineered Foods:
Health Issues
(Theoretical problems?)
 Lack of long term feeding trials
– animal studies, human studies
 Food allergies
– antifreeze protein from fish
 Labeling Issue
– Pros: consumer has the right to know
– Cons: unnecessary, no evidence of environmental/health concerns, will hurt sales and stymie further development

Protein Functions
 Enzymes & related proteins
– Catalysts
– Membrane transporters
– Cell receptors
©2001 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning
™ is a trademark used herein under license.

sodium pumps

Protein Functions
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Protein Functions
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 Protein Hormones
– Insulin
– Glucagon
 Amino Acid Derived Hormones
– serotonin
– adrenaline

Protein Functions
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– impaired immune system with protein deficiency
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– albumin
– edema

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– buffer
– acidosis & alkalosis
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– Unlike fats, amino acids can be converted into glucose (required for CNS/brain function)
 starvation
 low carbohydrate diets
– body cannibalizes body proteins to make glucose

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– Quantity of protein
– Quality of protein

– How well a protein meets the body’s need for health, growth, etc…
 Digestibility
 Amino acid composition
– Essential Amino Acids composition

 Measures of protein quality
 Biological Value (BV)
– Measures body retention of food protein
– BV=100 => 100% of food protein retained
 Protein Efficiency Ratio (PER)
– Measures ability of protein to support growth
– g growth/g protein fed
– PER=3 => 3g growth per g or protein fed

100
90
80
70
60
50
40
30
20
10
0
Protein Quality: BV
Egg
Milk
Beef
Soy
Peas
Rice
Wheat
Lentils

4
3.5
3
2.5
2
1.5
1
0.5
0
Protein Quality: PER
Egg
Milk
Beef
Soy
Peas
Rice
Wheat
Lentils

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 Vegetarian Diets
– Is there a protein problem?
Plant proteins are “Incomplete proteins”
 Complementary Proteins
– Example: Mexican Food
 Tortilla: low lysine, hi methionine
 Beans: low in methionine, hi lysine

Tortillas & Rice with Refried
Beans
© 2002 Wadsworth Publishing / Thomson Learning™

Hummus (garbanzo beans) and
Pita Bread (wheat)
© 2002 Wadsworth Publishing / Thomson Learning™

Peanut butter (legume)

Vegetarian Diets:
Why become a vegetarian?
 Health benefits
 Environmental concerns about meat based diets
 Animal welfare/ethical considerations
 Economic reasons
 World hunger issues
 Religious beliefs

Vegetarian Diets:
Potential Health Benefits
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Obesity
– % of obesity lower in vegetarian populations
Cardiovascular Disease
– Risk of CHD 31% lower in vegetarian men and 20% lower in vegetarian women
– Lower LDL-C, lower HDL-C
Hypertension
– 42% non-veg with hpt, 13% vegetarians
Also lower prevalence for
– Diabetes
– Cancer

Vegetarian Diets:
Consumer Trends - 2000
 2.5% of adult Americans are vegetarians
– 4.8 million people
– Slightly less than 1% are vegans
 20-25% of adult Americans eat 4 or more meatless meals weekly

“What do vegetarians in the United
States eat?”
Am J Clin Nutr. 78S:626-632 (2003)
 Continuing Survey of Food Intake by
Individual (CSFII): 1994-1996
– >13,000 subjects
 2 day food records
 2.5% considered themselves as vegetarian
– 36% of self-defined vegetarians actually consumed no meat
 ~4% of total consumed no meat

“What do vegetarians in the United States eat?”
Characteristics of Self-defined
Vegetarians
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Vegetarians were thinner
– BMI: 23 vs 26
Consumed more CHO
– 57% vs 50%
Less fat and saturated fat
– 27% vs 33% and 9% vs 11%
More vitamin A, carotene, vitamin E, vitamin C, folate, dietary fiber and less cholesterol

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– poultry, fish, dairy, eggs OK
 Nutritional Benefits
– Less fat, saturated fat, cholesterol
 Nutritional Concerns
– no special nutritional problems
– May not be any better than typical US diet
 may be high in fat, sat’d fat, salt
 cooking methods
 junk foods, convenience foods

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– Milk & eggs OK
 Nutritional Benefits
– Like non-meat vegetarians
 Nutritional Concerns
– No special nutritional problems
– May be high in fats, sat’d fats
 cheese & eggs

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– no animal foods
 Nutritional Benefits
– Low fats, high fiber, plant-based
 Nutritional Concerns
– protein quality
 probably OK, quantity may be an issue
– calcium
 no dairy, plant sources (leafy greens, soy), fortified foods (soy, rice milk)
– iron
 no meat, plant sources (leafy greens), cereals
– vitamin B-12
 probably OK, cereals & supplements

 Protein - Energy Malnutrition
– > 500 million children with PEM
– 33,000 die per day with PEM
 Two major forms of PEM
–Kwashiorkor
–Marasmus

 Kwashiorkor
– Ghana “the evil spirit that infects the first child when the second child is born”
 Protein low, Calories OK
 Symptoms
– edema
– enlarged fatty liver
– light colored hair
 low tyrosine/melanin
– skin lesions

 Marasmus
 Both Protein and Calories low
– inadequate food intake
 Symptoms
– wasting of lean and fat tissue
– weak, anemic, low metabolism
– death due to secondary infections

 RDA = 0.8g Pro/kg BW
–Or ~ 15% of calories
 M = 55 gP/d F = 45 gP/d
 Safety factor accounts for:
– individual differences
– varied protein quality
– average requirement 0.5-0.6gP/kg
 Typical Intake: 65 - 110 gP/d

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Most sport nutritionists recommend
– 1.0 to 1.5 g protein/kg BW
– RDA = 0.8 gP/kg BW
Example of athlete’s protein needs
 175 lb = 80 kg athlete
– 80 kg x 1.5gP/kg =
 120 g protein needed per day
 So do athletes need to supplement their diets? Usually not.
 3500 Cal/d x 15%Pro = 525 Cal Pro
– 525 Cal P / 4 Cal/gPro =
 131 g pro in normal diet

For maximal muscle gain:
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Adequate protein
– 1.2 – 1.5 gPRO/kg BW
 175 lbs = 80kg = 96-120gP/day
 If 3000 Cal diet = 13-16% of Calories
Adequate energy, especially Carbs
– 6-7g CHO/kg BW
 175 lbs = 480 –560 g CHO
 If 3000 Cal diet = 64% - 75%
Proper cellular hormonal balance
– Genetics
– Weight training
– Cheating (anabolic steroids, androstenedione
(prohormone)