Vitamin |
functions |
Deficency symptoms |
Sources |
Excessive |
A |
Formation and maintenance of skin, mucous membranes, bones, and teeth; vision; and reproduction |
is night blindness (difficulty in adapting to darkness), excessive skin dryness; lack of mucous membrane secretion, and dryness of the eyes due to a malfunctioning of the tear glands |
The body obtains vitamin A by manufacturing it from carotene, a vitamin precursor an by absorbing ready-made vitamin A from plant-eating organisms. In animal form, it is found in milk, butter, cheese, egg yolk, liver, and fish-liver oil. |
Excess vitamin A can interfere with growth, stop menstruation, damage red blood corpuscles, and cause skin rashes, headaches, nausea, and jaundice. |
Thiamine, or vitamin B1 |
catalyst in carbohydrate metabolism, enabling pyruvic acid to be absorbed and carbohydrates to release their energy. Also plays a role in the synthesis of nerve-regulating substances. |
Beriberi: muscular weakness, swelling of the heart, and leg cramps and may, in severe cases, lead to heart failure and death |
Pork, organ meats (liver, heart, and kidney), brewer's yeast, lean meats, eggs, leafy green vegetables, whole or enriched cereals, wheat germ, berries, nuts, and legumes. |
unknown |
Riboflavin, or vitamin B2 |
metabolism of carbohydrates, fats, and, especially, respiratory proteins. It also serves in the maintenance of mucous membranes |
skin lesions, especially around the nose and lips, and sensitivity to light |
liver, milk, meat, dark green vegetables, whole grain and enriched cereals, pasta, bread, and mushrooms. |
unknown |
Niacin, also known as nicotinic acid and vitamin B3 |
works as a coenzyme in the release of energy from nutrients |
pellagra: symptoms of which is a sunburn like eruption that breaks out where the skin is exposed to sunlight, a red and swollen tongue, diarrhea, mental confusion, irritability, and, when the central nervous system is affected, depression and mental disturbances |
liver poultry, meat, canned tuna and salmon, whole grain and enriched cereals, dried beans and peas, and nuts. The body also makes niacin from the amino acid tryptophan |
Large doses over long periods cause liver damage. |
Pyridoxine, or vitamin B6 |
Absorption and metabolism of amino acids. It also plays roles in the use of fats in the body and in the formation of red blood cells |
skin disorders, cracks at the mouth corners, smooth tongue, convulsions, dizziness, nausea, anemia, and kidney stones. |
whole (but not enriched) grains, cereals, bread, liver, avocadoes, spinach, green beans, and bananas |
unknown |
Cobalamin, or vitamin B12 |
formation of nucleoproteins, proteins, and red blood cells, and for the functioning of the nervous system. |
Cobalamin deficiency is often due to the inability of the stomach to produce glycoprotein, which aids in the absorption of this vitamin. Pernicious anemia results, with symptoms of ineffective production of red blood cells, faulty myelin (nerve sheath) synthesis, and loss of epithelium (membrane lining) of the intestinal tract |
only from animal sources-liver, kidneys, meat, fish, eggs, and milk. Vegetarians are advised to take vitamin B12 supplements. |
unknown |
Folic acid, or folacin |
needed for forming body protein and hemoglobin. Folic acid is effective in the treatment of certain anemias and sprue. |
folic acid deficiency may be responsible for neural tube defects, a type of birth defect that results in severe brain or neurological disorders |
Dietary sources are organ meats, leafy green vegetables, legumes, nuts, whole grains, and brewer's yeast. |
unknown |
B5 Pantothenic acid |
Metabolism of lipids, proteins and carbohydrates. contributes to the synthesis of steroids, porphyrins, acetylcholine and other substances. |
Unknown |
Manufactured by intestinal bacteria and widespread in foods |
unknown |
Biotin |
formation of fatty acids and the release of energy from carbohydrates |
Unknown |
synthesized by intestinal bacteria and widespread in foods |
unknown |
Vitamin C, or Ascorbic Acid |
important in the formation and maintenance of collagen, the protein that supports many body structures and plays a major role in the formation of bones and teeth. It also enhances the absorption of iron from foods of vegetable origin. ascorbic acid has been shown to prevent the formation of nitrosamines-compounds found to produce tumors in laboratory animals and possibly also in humans |
. Scurvy - loss of the cementing action of collagen and include hemorrhages, loosening of teeth, and cellular changes in the long bones of children |
citrus fruits, fresh strawberries, cantaloupe, pineapple, and guava. Good vegetable sources are broccoli, brussels sprouts, tomatoes, spinach, kale, green peppers, cabbage, and turnips. |
prolonged doses can result in the formation of bladder and kidney stones, interference with the effects of blood-thinning drugs, destruction of B12, and the loss of calcium from bones. |
Vitamin D |
necessary for normal bone formation and for retention of calcium and phosphorus in the body. It also protects the teeth and bones against the effects of low calcium intake by making more effective use of calcium and phosphorus. |
Rickets, is characterized by deformities of the rib cage and skull and by bowlegs, due to failure of the body to absorb calcium and phosphorus. |
egg yolk, liver, tuna, and vitamin-D fortified milk. It is also manufactured in the body when sterols, which are commonly found in many foods, migrate to the skin and become irradiated |
vitamin poisoning, kidney damage, lethargy, and loss of appetite. |
Vitamin E |
vitamin plays some role in forming red blood cells and muscle and other tissues and in preventing the oxidation of vitamin A and fats. |
Unknown |
vegetable oils, wheat germ, liver, and leafy green vegetables. |
overdoses appear to have lower toxic effects than do overdoses of other fat-soluble vitamins |
Vitamin K |
mainly for the coagulation of blood. It aids in forming prothrombin, an enzyme needed to produce fibrin for blood clotting. |
Digestive disturbances may lead to defective absorption of vitamin K and hence to mild disorders in blood clotting. |
All leafy green vegetables, egg yolks, soybean oil, and liver. For a healthy adult, a normal diet and bacterial synthesis in the bowels usually are sufficient to supply the body with vitamin K and prothrombin |
Unknown |