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Nutrition
K. Dunlap
Nutrition
the study of food and how the body uses it
Function of Nutrients:
1) supply energy
2) supply materials for building and
replacing body tissues
3) supply other substances needed for
various life processes
Nutrition
• Nutrients: the components of food and drink
that provide growth, replacement, and energy:
1. Carbohydrates
2. Lipids
3. Proteins
4. Vitamins
5. Minerals
6. Water
• Digestion: the hydrolysis of starches, fats, and
proteins into smaller units that can be
absorbed and metabolized.
DRI- Dietary Reference index
Food and Nutrition Board, the institute of Medicine and
the National Academy of Sciences has established the
DRIs
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Estimated Average Requirement (EAR)
Estimated Energy Requirement (EER)
Recommended dietary allowances (RDA)
Adequate Intake (AI)
Tolerable Upper Level Intake (UL)
• EAR: The average daily nutrient intake level estimated to meet the
requirement of half the healthy individuals in a particular life stage and
gender group.
• EER: is the average dietary energy intake that is predicted to maintain
energy balance in healthy, normal weight individuals of a defined age,
gender, weight, height, and level of physical activity consistent with good
health
• RDA: average daily level of intake sufficient to meet the nutrient
requirements of nearly all (97%-98%) healthy people.
• AI: established when evidence is insufficient to develop an RDA & EARs
and is set at a level assumed to ensure nutritional adequacy.
• UL: The highest average daily nutrient intake level that is likely to pose no
risk of adverse health effects to almost all individuals in the general
population.
Calorimeter
• Food energy is measured in Calories (capital C)
1 Cal = 1 kcal = 1000 cal = 4180 joules
• a Calorie is defined
as the amount of
energy required to
raise 1 kg of water 1C
•Measured in a bomb
calorimeter
Caloric Value of Food
Carbohydrate = 4 Cal per gram
Proteins
= 4 Cal per gram
Fats
= 9 Cal per gram
Recommended Dietary Needs
Nutrition & Health
Poor diet and sedentary life style = Risk
factors chronic diseases
Accounts for about 66% of all deaths
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Cardiovascular diseases (29%)
Cancer (22%)
Cerebrovascular diseases (7%)
Diabetes (3%)
Nutritional Diseases
Obesity - excessive weight gain that is
associated with heath concerns and
increased risk of mortality
-characterized by a BMI of greater than 30
BMI (body mass index) = weight in kg
divided by the square of the height in m
-35.7% of Americans are obese
-68.8% of Americans are overweight (BMI
25-29.9)
Nutritional Diseases
Diabetes - condition in which body is
unable to utilize glucose in a normal way
Type I - an auto immune disease that
results in the permanent destruction of
insulin producing beta cells in the pancreas
Type II - metabolic disorder that is usually
characterized by insulin resistance, insulin
deficiency and hyperglycemia
-associated with obesity
-Increased prevalence
Metabolic syndrome
Is a cluster of at least three of five of the
following medical conditions:
•abdominal (central) obesity
•Elevated fasting plasma glucose
•High serum triglycerides
•Low HDL
•Insulin resistance – a condition in which the
body does not respond properly to insulin.
Type 2 diabetes
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US population: 9.3%
7th leading cause of death
AI/AN: 15.9%
Alaskan Natives alone (5-9%)
a
subsistence lifestyle
• low incidence of age and nutritional diseases
• 4.8 kg subsistence foods per week
• 60% of subsistence foods is finfish
Proteins
Human body is 10-20% protein
• 40-50% in skeletal muscle
• 20% in organs
• Rest in skin and blood
Recommended Dietary Intake:
Adults: 0.8 g per kg of body weight
Children and Pregnancy: 1.5-2.0 g per kg body weight
Complete Protein - contains all essential amino acids
-meat, eggs, dairy, fish
Incomplete Protein - missing one or more essential amino acids
-legumes and grains combined make a complete
protein
Proteins
– Gelatin, which is denatured collagen, is an
incomplete protein because it lacks Trp, and is low
in Ile and Met.
– Corn protein is low in Lys and Trp.
– Rice is low in Lys and Thr.
– Wheat protein is low in Lys.
– Legumes are low in Met and Cys.
– Soy protein is very low in Met.
Protein complementation: a diet in which two or
more proteins complementation each other’s
deficiencies; for example:
– grains + legumes (rice + beans)
Fats
Essential Fatty acids:
Omega-3
EPA, DHA, linoleic
• recommended 30% of diet
-10% monounsaturated
-10% saturated
-10% unsaturated
Omega-6
Arachidonic acid, -linolenic
• EPA, DHA, AA are 20
carbon hormone-like
fatty acids that play an
important part in the
immune function
Saturated Fats in the U.S. Diet
>90% of FAs in US diet:
• Palmitic (16:0)
• Stearic (18:0)
• Oleic (18:1)
• Linoleic (18:2)
Percentage of Calories in
Common Foods
Energy Needs
Woman
Men
2000 Cal
2200 Cal
-physical activity and lifestage affects energy
needs
-need to burn 3500 Cal to lose 1 pound
Basal Caloric Requirements -the requirements
for a resting body
Basal Metabolic Rate
• The amount of energy expressed in calories that a person
needs to keep the body functioning at rest
• Includes breathing, blood circulation, controlling body temp,
cell growth, brain and nerve function, and muscle
contraction.
• Affects the rate a person burns calories and ultimately
whether they individual maintains, gains or loses weight.
• Accounts for about 60-70% of the daily calorie expenditure
by individuals
• influenced by several factors
• BMR typically declines by 1-2% per decade after age 20,
mostly loss of muscle
Problems with Processed Food
• nutrients are lost in processing
• some but not all nutrients are
added back (Enriched)
• Fortified is when other
ingredients are added
that were not originally
the food
• are lower in fiber
• processed foods are
digested more quickly and
lend to weight gain
Food Supplements
- vitamins, minerals, herbal remedies, etc…
-$60 billion a year industry
-Balanced diet provides adequate needs
-Elderly, dieters, alcoholics, pregnant, lactation
may require supplementation
- often supplements are not in a form that is as
available as it is in food
Supplement
Label
Nutrition
Labels
Food Additives
-added to prevent spoilage, sweeten,
enhance flavor, color, appearance, emulsify
Food Preservatives
-mostly used to prevent food spoilage
Antimicrobial:
Nitrites
-clostridium botulism
- identified as cancer-causing
Sulfites
-wine and dried fruit
-can cause allergic rxn
Others
-Na, K, Ca salts, benzoic acid, propionic acid, sorbic acid
Food Preservatives cont….
Antioxidants: added to slow the oxidative
process
-usually phenols
Butylated hydroxyanisole (BHA) and butylated
hydroxytoluene (BHT)
-Prevent oxidation of fats by combining with free radicals
Natural Antioxidants
-Vitamin E, Vitamin C, carotenoids, other polyphenols
-also stop oxidation by combining with free radicals
Chemical Structures of Flavorings
-largest class of food additive
-natural and
synthetic
-Mostly
aldehydes and
esters
-Many
synthetics
have not been
thoroughly
tested
Chemical Structures of
Artificial Sweeteners
-growing market for dieters and diabetics
Sucralose
Splenda
NutriSweet
Sweetness of Sweeteners
1. How does the body store energy?
2. How many Cal of energy are released 180 grams of
glucose are converted to CO2 and H2O?
3. There are 2 fatty acids that the body needs but cannot
synthesize. What are they?
4. What is meant by a complete protein?