HTF 200: INTRODUCTION TO NUTRITION

CHAPTER 5: VITAMINS

Characteristics of vitamins:

      Very small amounts of vitamins are needed by the human body, and very small amounts are present in foods.

      Although vitamins are needed in small quantities, the roles they play in the body are enormously important.

      Vitamins must be obtained through foods, because vitamins either are not made in the body or are not made in sufficient quantities. There is no perfect food that contains all the vitamins in just right amounts.

      Vitamins have no kcalories.

      Some vitamins in foods are not the actual vitamin but rather are precursors. The body chemically changes the precursor to the active form of the vitamin.

      Vitamins are classified according to how soluble they are in fat or water. Fat-soluble vitamins are generally stored in the body, whereas water-soluble vitamins (except B6 and B12) are readily excreted.

FAT – SOLUBLE VITAMINS

1.       Vitamin A

Ø  Functions of vitamin A:

      Maintains the health of the eye and vision.

      Promotes healthy surface linings of the lungs, gastrointestinal tract, and urinary tract.

      Promotes normal reproduction.

      Promotes growth and development, including bones and teeth.

      Regulates the immune system so it can fight off infection.

Ø  Recommended intake:

RDA:

      Men: 900micrograms RAE

      Women: 700 micrograms RAE

Upper intake level:

      3000 microgram/day of preformed vitamin A

Ø  Sources: Preformed; liver, fortified milk, fortified cereals, eggs. Beta-carotene; dark vegetables, deep orange fruits and vegetables.

2.       Vitamin D

Ø  Functions of vitamin D:

      Maintenance of blood calcium and phosphorus levels so that calcium can build bones and teeth.

      Bone growth.

Ø  Recommended intake:

AI: 5 micrograms cholecalciferol (31-50 years old), 10 micrograms cholecalciferol (51-70+ years old)

Upper intake level: 50 micrograms cholecalciferol

Ø  Sources: sunshine, fortified milk, fortified cereals, fatty fish, fortified butter and margarine.

3.       Vitamin E

Ø  Functions of vitamin:

      Antioxidant especially helps red blood cells and cells in lungs and brains.

Ø  Recommended intake:

RDA: 15 mg alpha-tocopherol

Upper intake level: 1000 mg alpha-tocopherol

Ø  Sources: vegetables oils, margarine, shortening, salad dressing, nuts, seeds, leafy green vegetables, whole grains, fortified cereals.

4.       Vitamin K

Functions of vitamin:

      Blood clotting

      Healthy bones

Recommended intake:

AI: Men- 120 micrograms, Women- 90 micrograms

Sources: green leafy vegetables, vegetable oils and margarine; made in intestine

WATER-SOLUBLE VITAMINS

VITAMIN	RECOMMENDED INTAKE	FUNTIONS	SOURCES
Vitamin C	RDA: Men-90mg; Women- 75mg Upper intake level: 2000mg	Collagen formation       Wound healing       Synthesis of some hormones       Healthy immune system       Antioxidant       Absorption of iron	Citrus fruits, bell peppers, kiwi fruit, strawberries, tomatoes, broccoli, potatoes; fortified juices, drinks and cereals.
Thiamin	RDA: Men-1.2mg; Women- 1.1mg Upper intake level: none	Part of coenzyme in energy metabolism       Nerve function	Pork, dry beans, whole-grain etc.
Riboflavin	RDA: Men-1.3mg; Women- 1.1mg Upper intake level: none	Part of coenzyme in energy metabolism	Milk, milk products, organ meats, whole grains etc.
Niacin	RDA: Men-16mg; Women- 14mg Upper intake level: 35mg	Part of coenzyme in energy metabolism	Meat, poultry, fish, organ meats, whole grain etc.
Vitamin B6	RDA: 1.3 mg Upper intake level: 100mg	Part of coenzyme involved in carbohydrate, fat, and protein metabolism       Synthesis hemoglobin and some neuro-transmitters       Important for immune system	Meat, poultry, fish, potatoes, fruits, vegetables, fortified cereals.
Folate	RDA: 400micrograms Upper intake level: 1000micrograms	Part of coenzyme required to make DNA and new cells       Amino acids metabolism	Green leafy vegetables, fortified cereals, legumes, orange juices.
Vitamin B12	RDA: 2.4micrograms Upper intake level: none	Part of coenzyme required to make DNA and new cells       Conversion of folate into active coenzyme form       Normal functioning of nervous system       Healthy bones	Animal foods such as meat, poultry, fish, eggs etc.
Pantothenic acid	RDA: 5mg; Upper intake level: none	Part of coenzyme in energy metabolism	Fortified cereals, beef, poultry, mushrooms etc.
Biotin	RDA: 30micrograms Upper intake level: none	Part of coenzyme in energy metabolism and synthesis fat and glycogen	Egg yolks, widespread, made in intestine.
Choline	AI: Men-550mg; Women- 425mg Upper intake level: 3500mg	Synthesis neuro-transmitter       Synthesis of lecithin found in cell membranes	Widespread, milk, eggs, peanuts.

Reference: Drummond, K. E. & Brefere, L. M. (2010). Nutrition for foodservice and culinary professionals. New Jersey: John Wiley & Sons Inc.