A group of substances essential to normal metabolism, growth and
development, and regulation of cell function; vitamins work together with
enzymes, co-factors, and other substances.
Each vitamin has specific functions. If a certain vitamin is deficient, a deficiency disease results.
Vitamin A: this fat-soluble vitamin helps in the formation and maintenance of healthy teeth, skeletal and soft tissue, mucous membranes, and skin. It is also known as retinol, as it generates the pigments that are necessary for the
working of the retina. It promotes good vision, especially in dim light. It may
also be required for reproduction and lactation. Beta carotene is a precursor to vitamin A; it has antioxidant properties.Side Effects
Vitamin A deficiency can increase the susceptibility to infectious diseases, as
well as cause vision problems.
Large doses of vitamin A can be toxic. They can also cause abnormal fetal
development in pregnant women. Increased amounts of beta-carotene can turn the color of skin to yellow or orange. The skin color returns to normal once the increased intake of beta-carotene is reduced.Vitamin B1:
Thiamine(B1), helps the body cells convert carbohydrates into energy. It is also essential for the functioning of the heart and for healthy nerve cells and the brain.Side Effects
A deficiency of thiamine can cause weakness, fatigue, and nerve damage. A total absence of thiamine can cause the disease called beriberi, which is very
rare in the United States. There is no known toxicity to thiamine.Vitamin B2:
Riboflavin (vitamin B2) is A water-soluble vitamin required by the body for health, growth and reproduction; one of the B-complex vitamins.
Riboflavin (B2) works with the other B vitamins. It is important for body growth and red cell production, and helps in releasing energy from carbohydrates.Side Effects
Deficiency of riboflavin is not common in the U.S. because this vitamin is
plentiful in the food supply. Deficiency symptoms include dry and cracked skin and eyes that are sensitive to bright light.
There is no known toxicity to riboflavin. Because riboflavin is a water-soluble vitamin, excess amounts are excreted.Vitamin B6:
Vitamin B6, is also known as pyridoxine. The more protein a person eats the more B6 is required to use the protein. It helps in the formation of red blood cells and in the maintenance of normal brain function. It also assists in the synthesizing of antibodies in the immune system.Side Effects
Large doses of vitamin B6 can cause neurological disorders and numbness.
Deficiency of this vitamin is not common in the United States.Vitamin B12:
Vitamin B12, like the other B vitamins, is important for metabolism. It helps in the formation of red blood cells and in the maintenance of the central nervous system.Side Effects
There is no known nutritional deficiency of vitamin B12, but an inability to
absorb it can cause pernicious anemia.Pantothenic acid:
Pantothenic acid and biotin: pantothenic acid is essential for the metabolism of food. It is also essential in the synthesis of hormones and cholesterol. Biotin is essential for the metabolism of proteins and carbohydrates like the other B vitamins, and in the synthesis of hormones and cholesterol.Side Effects
There are no known deficiencies of either pantothenic acid or biotin. Large doses of pantothenic acid do not produce symptoms other than (possibly) diarrhea. There are no known toxic symptoms associated with biotin.Folacin:
Folacin works with vitamin B12 in the production of red blood cells. It is
necessary for the synthesis of DNA, which controls heredity as well as tissue growth and cell function.Side Effects
Folacin deficiency may cause poor growth, graying hair, inflammation of the tongue (glossitis), mouth ulcers, peptic ulcer, and diarrhea. It may also result in hemolytic and megaloblastic anemias.
Doses of folacin that greatly exceed the RDA may obscure a serious condition called pernicious anemia.Vitamin C:
Vitamin C is also known as ascorbic acid. It promotes healthy teeth and gums,helps in the absorption of iron, and in the maintenance of normal connective tissue. It also promotes wound healing.Side Effects
A deficiency of vitamin C causes the disease scurvy, which is rare in the United States.
Toxicity does not normally occur, since vitamin C is water soluble and is
regularly excreted by the body. Diarrhea is a possible (but uncommon)
symptom associated with increased intake of vitamin C.Vitamin D:
Vitamin D is also known as the "sunshine vitamin" since it is manufactured by the body after being exposed to sunshine. Ten to fifteen minutes of sunshine three times weekly is adequate to produce the body's requirement of vitamin D. It promotes the body's absorption of calcium, which is essential for the normal development of healthy teeth and bones. It also helps maintain the adequate blood levels of calcium and phosphorus, which are minerals.Side Effects
A vitamin D deficiency leads to soft bones or rickets.
Large doses of vitamin D can result in calcium being reabsorbed from the bones and being deposited in soft tissues, such as the heart and lungs, reducing their ability to function.Vitamin E:
Vitamin E is also known as tocopherol; it is an antioxidant. It is also important in the formation of red blood cells and the use of vitamin K.
There is no known dietary deficiency of vitamin E.
There are no known toxic effects to megadoses of vitamin E. Occasional side effects such as headache have been reported.Vitamin K:
Vitamin K is known as the clotting vitamin, because without it blood would not coagulate. Some studies indicate that it helps in maintaining strong bones in the elderly.