Nutrition

K. Dunlap

Nutrition

the study of food and how the body uses it

Function of Nutrients:1) supply energy2) supply materials for building and

replacing body tissues3) supply other substances needed for

various life processes

Nutrition• Nutrients:Nutrients: the components of food and drink

that provide growth, replacement, and energy:1. Carbohydrates2. Lipids3. Proteins4. Vitamins5. Minerals6. Water

• DigestionDigestion: the hydrolysis of starches, fats, and proteins into smaller units that can be absorbed and metabolized.

DRI- Dietary Reference indexFood and Nutrition Board, the institute of Medicine and Food and Nutrition Board, the institute of Medicine and the National Academy of Sciences has established the the National Academy of Sciences has established the DRIsDRIs

•Estimated Average Requirement (EAR)Estimated Average Requirement (EAR)•Estimated Energy Requirement (EER)Estimated Energy Requirement (EER)•Recommended dietary allowances (RDA)Recommended dietary allowances (RDA)•Adequate Intake (AI)Adequate Intake (AI)•Tolerable Upper Level Intake (UL)Tolerable Upper Level Intake (UL)

• EAR: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.

• EEREER: 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: RDA: average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%-98%) healthy people.

• AIAI: established when evidence is insufficient to develop an RDA & EARs and is set at a level assumed to ensure nutritional adequacy.

• ULUL: 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 1C

•Measured in a bomb calorimeter

Caloric Value of Food

Carbohydrate = 4 Cal per gramProteins = 4 Cal per gramFats = 9 Cal per gram

Recommended Dietary Needs

Nutrition & HealthPoor diet and sedentary life style = Risk factors chronic diseases

Accounts for about 66% of all deaths

•Cardiovascular diseases (29%)•Cancer (22%)•Cerebrovascular diseases (7%)•Diabetes (3%)

Nutritional DiseasesObesity - 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 DiseasesDiabetes - 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

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.

Metabolic syndrome

• US population: 9.3%• 7th leading cause of death• AI/AN: 15.9%• Alaskan Natives alone (5-9%)

Type 2 diabetes

• low incidence of age and nutritional diseases• 4.8 kg subsistence foods per week• 60% of subsistence foods is finfish

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

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:Protein complementation: a diet in which two or more proteins complementation each other’s deficiencies; for example:– grains + legumes (rice + beans)

Fats • recommended 30% of diet-10% monounsaturated-10% saturated-10% unsaturated

Essential Fatty acids:Omega-3

EPA, DHA, linoleic

Omega-6Arachidonic 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 NeedsWoman 2000 CalMen 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

• 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

Basal Metabolic Rate

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 andlend 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

SupplementLabel

NutritionLabels

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

NutriSweet

SucraloseSplenda

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?