VITAMINS
Vitamins are organic compounds that help maintain normal body functions, such as reproduction, growth and cell repair. Vitamins work with other vitamins and other substances like enzymes to help your cells function correctly, and an adequate consumption of vitamins is necessary for your body to work well. Your body can't manufacture vitamins, so you need to obtain them from other sources.
Most of the vitamins you need come from the food you eat, except for vitamin D, which your body makes when exposed to sunlight, and K, which is made by the bacteria in your intestines. In addition to their presence in natural foods, vitamins can also be manufactured synthetically.
Some people who feel that they aren't getting enough vitamins in the foods they eat or who have a health condition such as pregnancy will take a synthetic vitamin to ensure adequate vitamin intake. Vitamin supplements may be available in tablet, caplet or liquid form. Although the Food and Drug Administration (FDA) regulates vitamin supplements, they do not have established standards for quality. However, the United States Pharmacopeia recently established standards for vitamin supplements, so look for supplements that say "USP" on the product label.
Nutritionists categorize vitamins by the materials that a vitamin will dissolve in. There are two categories: water-soluble and fat-soluble vitamins. Water-soluble vitamins, which include the B-complex group and vitamin C, travel through the bloodstream. Whatever water-soluble vitamins are not used by the body are eliminated in urine, which means you need a continuous supply of them in your food.
Fat-soluble vitamins—vitamins A, D, E and K—are stored in the fat tissues of the body for a few days to up to 6 months. If you get too much of a fat-soluble vitamin, it can be stored in your liver and may sometimes cause health problems.
Vitamin
Dietary Source
Major Functions
Signs of Prolonged Deficiency
Toxic Effects Of Major Doses
Vitamin A
Liver, milk, butter, cheese, carrots, spinach.
Maintenance of vision, skin, linings of nose, mouth, digestive and urinary tracts.
Night blindness; dry, scaling skin; loss of appetite; anemia; kidney stones.
Headache, vomiting and diarrhea, vertigo, double vision, liver damage, bone defects.
Vitamin D
Milk, fish oils, butter, egg yolks, sunlight.
Maintenance of bones and teeth; promotion of calcium absorption.
Bone softening, loss, and fractures in adults.
Kidney damage; calcium deposits in soft tissues, depression, and death.
Vitamin E
Vegetable oils, whole grains, nuts & seeds, green leafy vegetables, asparagus, peaches.
Protection and maintenance of cellular membranes.
Red blood cell breakage and anemia, weakness, neurological problems, muscle cramps.
Relatively non-toxic, but may cause excess bleeding or formation of blood clots.
Vitamin C
Peppers, broccoli, spinach, brussel sprouts, citrus fruits, berries, tomatoes, potatoes, cabbage
Maintenance and repair of connective tissue, bones, teeth, and cartilage; promotion of healing and iron absorption
Scurvy, anemia, loose teeth, joint pain, poor healing, hair loss
Urinary stones, acid stomach, nausea, diarrhea, headache, fatigue
Thiamin
Whole-grain and enriched breads and cereals, organ meats, lean pork, nuts, legumes
Conversion of carbohydrates into usable forms of energy; maintenance of nervous system function
Beriberi (symptoms include muscle wasting, mental illness, anorexia, enlarged heart, nerve changes, abnormal heart rhythm)
None
Riboflavin
Dairy products, enriched breads and cereals, lean meats, poultry, fish, green vegetables
Energy metabolism; maintenance of skin and nervous system
Cracks at corners of mouth; sore throat; skin rash; hypersensitivity to light; purple tongue
None
Niacin
Conversion of carbohydrates, fats and proteins into usable energy
Pellagra (symptoms include diarrhea, dermatitis, inflammation of mucus membranes, dementia)
Flushing of skin, nausea, vomiting, diarrhea, liver dysfunction, glucose intolerance
Headache, vomiting and diarrhea, vertigo, double vision, liver damage, bone defects
Vitamin B6
Eggs, poultry, fish, whole grains, nuts, soybeans, liver, kidney, pork
Protein and neurotransmitter metabolism; red blood cell synthesis
Anemia, convulsions, cracks at corners of mouth, dermatitis, nausea, confusion
Neurological abnormalities and damage
Foliate
Green leafy vegetables, yeast, oranges, whole grains, and legumes, liver
Amino acid metabolism, synthesis of RNA and DNA, new cell synthesis
Anemia, weakness, fatigue, irritability, shortness of breath, swollen tongue
Masking of vitamin B12 deficiency
Vitamin B12
Eggs, milk, meats, other animal foods
Metabolic reactions; synthesis of red and white blood cells
Anemia, fatigue, nervous system damage, sore tongue
None
Biotin
Cereals, yeast, egg yolks, soy flour, liver; widespread in foods
Metabolism of fats, carbohydrates, and proteins
Rash, nausea, vomiting, weight loss, depression, fatigue, hair loss
None
Pantothenic Acid
Animal foods, whole grains, legumes; widespread in foods
Metabolism of fats, carbohydrates, and proteins
Fatigue, numbness of hands and feet, gastrointestinal disturbances
None
