• Amino acids are the building blocks of proteins.

· The human body can synthesize all of the amino acids necessary to build all human proteins except for the ten amino acids called the Essential Amino Acids: isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine, histidine, arginine.

· Amino acids are typically found in meat and dairy products.
· Amino acids can also be supplied by a combination of cereal grains like corn, wheat, rice with legumes like beans and peanuts.
· Some popular food combinations contain the ten essential amino acids completing your protein requirements:
Mexican corn and beans
Japanese rice and soybeans
Cajun red beans and rice

Reference: Department of Health and Human Services and Department of Agriculture: Dietary Guidelines for Americans 2005

February 4, 2009

· Nutritional requirements have been commonly expressed by Food and Nutrition Board of the National Academy of Sciences in the form of the Recommended Dietary Allowances (RDAs).

· Recommended Dietary Allowances RDAs have been established for:
· carbohydrate intake
· protein intake
· water-soluble vitamins: thiamine, riboflavin, niacin, vitamin B6, folate, vitamin B12, and vitamin C
· fat-soluble vitamins: A, D, and E; and K
· minerals: copper, phosphorus, magnesium, iron, zinc, iodine, molybdenum, and selenium.

February 4, 2009

• Minerals essential for normal function are grouped as:

· Major minerals:
calcium
magnesium
phosphorus

·Electrolytes:
sodium
potassium
chloride

· Trace elements: iron, zinc, copper, manganese, molybdenum, fluoride, iodine, cobalt, chromium, and selenium.

February 4, 2009

• Vitamins are organic molecules required by the body for a variety of essential functions.

· Water-soluble vitamins are: thiamine, riboflavin, niacin, vitamin B6 (pyridoxine), vitamin B12 (cobalamin), folate, pantothenic acid, biotin, and vitamin C (ascorbic acid).

· Fat-soluble vitamins are: Vitamin A, Vitamin D, Vitamin E, and Vitamin K.

February 4, 2009

• Cholesterol is one of the major components of cell membranes.

· Cholesterol is synthesized by the body and therefore is not an essential nutrient.

· Diets that contain large amounts of cholesterol partially inhibit the body's ability to make cholesterol but  ultimately there is an increase in serum cholesterol concentrations because of suppression of synthesis of low-density lipoprotein receptors.

· Average American diets contain approximately 450 mg/d of cholesterol, but 300 mg or less per day is optimal.

February 4, 2009

• Dietary fat is the most concentrated source of food energy equal to about 9 kilocalories per gram.

· Dietary fat also provides the essential fatty acid linoleic acid which is very important in normal metabolism.

· Other than the need for adequate quantities of linoleic acid, there is no specific requirement for dietary fat.

· Diets containing as little as 5-10% of total calories as fat appear to be safe and well tolerated.

• Dietary fats are composed primarily of fatty acids and dietary cholesterol.
· Fatty acids molecules contain either no carbon double bonds (saturated), one carbon double bond (monounsaturated), or more than one carbon double bond (polyunsaturated).
· Saturated fatty acids are associated with increased serum cholesterol.
· Polyunsaturated and monounsaturated fatty acids lower serum cholesterol.

· Trans-fatty acids are a particular form of unsaturated fat found in partially hydrogenated vegetable oils and is known to raise serum cholesterol levels.

· Saturated fats are solid at room temperature and in general are derived from animal foods.

· Unsaturated fats are liquid at room temperature and in general are derived from plant foods.

· The Polyunsaturated fatty acid linoleic acid is an essential nutrient and is required by the body for the synthesis of arachidonic acid, the major precursor of prostaglandins.

· Deficiency of linoleic acid results in dermatitis, hair loss, and impaired wound healing.

· Approximately 5 grams of linoleic acid per day is required to prevent essential fatty acid deficiency.

February 4, 2009

• Dietary fiber is that portion of plant matter that cannot be digested or absorbed by the human intestine.

·  Fiber increases the bulk of the stool and helps excretion.

· Diets high in dietary fiber are associated with a lower incidence of digestive and cardiovascular diseases.

February 4, 2009

• A small amount of carbohydrates (approximately 100 grams per day) are necessary to prevent starvation-induced fat breakdown.

·Dietary carbohydrates include:
· simple sugars
· complex carbohydrates (starches)
· indigestible carbohydrates (dietary fiber/bran)- carbohydrates that are not digestible.

• Most dietary carbohydrates should come from complex carbohydrates as found in whole grains and from sugars as found in fruits and vegetables.
· Sucrose (table sugar) and other forms of concentrated (simple) sugar, such as high fructose corn syrup, are dietary sources of excessive calories and are associated with obesity and risk of diabetes.

February 4, 2009

• Protein is required for growth and for maintenance of body structure and function.

• The Recommended Dietary Allowance (RDA) for protein is:
· 56 grams of protein per day for men
· 45 grams of protein per day for women.

February 4, 2009

Basal energy expenditure (BEE) is the amount of energy the human body requires to maintain basic physiologic functions (heart beat, breathing, nervous activity).

Thermic effect of food (TEF) is the amount of energy expended ingesting and digesting food.  This averages about 10% of the Basal energy expenditure.

Physical Activity has a major impact on energy expenditure.

February 4, 2009

· The human body requires energy to support normal functions, physical activity, growth, and repair of damaged tissues.

· Energy derived primarily from the oxidation or utilization of dietary carbohydrates or sugars.

· When your body has a deficiency in carbohydrates (sugars) from your diet, your body can modify proteins, fats and alcohol and use them for energy.

· Oxidation (burning) or utilizing of 1 gram of carbohydrate provides about 4 kcal (kilocalories) of energy.
· Utilization of 1 gram of protein can provide 4 kcal of energy.
· Utilization of 1 gram of fat can provide 9 kcal of energy.

• It is important to understand that calories from carbohydrates do not equal calories from proteins or calories from fats.

· Calories from carbohydrate (sugars) are much more easily burned than calories from protein or fats and therefore carbohydrate calories have more energy and potential for weight gain.
· Human physiology primarily uses the calorie from carbohydrate (sugars) for energy and will only utilize calories from fats or proteins in a starvation state.

· Therefore dietary carbohydrate restriction is the most effective manner to loss weight.

February 4, 2009

• Nutrients are essential compounds needed for healthy metabolism.

• Essential nutrients cannot be made or synthesized by the human body.

• There are approximately 40 nutrients.

• A deficiency in a nutrient can cause physiologic abnormalities that when replaced, should disappear.

• Essential nutrients include:
· essential amino acids (amino acids that cannot be made by the human body and must come form the diet)
· water-soluble vitamins
· fat-soluble vitamins
· minerals
· essential fatty acids (fatty acids that cannot be made by the human body and must come from the diet)

• The human body also requires:
· adequate energy substrate
· a small amount of usable carbohydrates
· indigestible carbohydrate (fiber/bran)
· additional nitrogen
· water

February 4, 2009

· Vitamin D is the fat-soluble vitamin that functions to maintain the calcium balance of your body. 
· Vitamin D stimulates dietary calcium absorption in the intestine and calcium deposition in bones.
· Vitamin D deficiency causes the disease Rickets which is a bone disorder.
· Vitamin D functions as a hormone more than vitamin.

· Vitamin D comes in different forms:
vitamin D2 (called ergocalciferol) is the dietary form of vitamin D found in plants, multiple vitamins and milk.
vitamin D3 (called cholecalciferol) is the form made from the exposure of skin to sunlight.

· Vitamin D recommended daily requirements:
There is no consensus regarding Vitamin D daily requirements.
The recommended dietary allowance of vitamin D for infants and children is 400 IU but this dose was based on a previously common dose equivalent of a teaspoon (5 ml) of cod liver oil.
This has traditionally been considered safe and effective in preventing Rickets.
Adults require less vitamin D than infants and children so the adult dose was set arbitrarily at 200 IU.
The optimal dose of vitamin D is not known.

· Recent studies have shown lower levels of vitamin D is becoming more common and that there has been an increase in cases of of vitamin D-dependent Rickets.
· Lower vitamin D levels are likely related to the use of sunscreen and sunlight avoidance.

· Vitamin D receptors are found in cells throughout the body and vitamin D likely has many more functions other than just regulating calcium levels.
· Vitamin D deficiencies and complications associated with low vitamin D levels are only recently being appreciated by the medical community.