Vitamin B-6

Vitamin B-6, also called pyridoxine, is one of eight water-soluble B vitamins. Vitamin B6 (pyridoxine) serves as coenzyme and is involved in the metabolism of protein and carbohydrates, the production of insulin and red and white blood cells, and the synthesis of neurotransmitters, enzymes, and prostaglandins. Vitamin B-6 is essential in numerous biochemical pathways involving red blood cells, the immune system, central nervous system function, protein metabolism, homocysteine metabolism, and also the production of energy.

Pyridoxine is an especially important vitamin for maintaining healthy nerve and muscle cells and it aids in the production of DNA and RNA, the body's genetic material. It is necessary for proper absorption of vitamin B-12 and for the production of red blood cells and cells of the immune system.

Vitamin B-6 is indicated for the treatment of sideroblast anemia, neurologic disturbances, seborrhoeic dermatitis, and cheilosis. In combination with folic acid and Vitamin B-12, Vitamin B-6 lowers homocysteine levels which is an amino acid linked to heart disease and stroke, and possibly other diseases as well, such as osteoporosis, and Alzheimer's disease. Pyridoxine is required for the balancing of hormonal changes in women as well as assisting the immune system and the growth of new cells.

Vitamin B-6 may be helpful in some women with premenstrual dysphoric disorder, also known as premenstrual syndrome (PMS), and may be useful in some cases of gestational diabetes and for protection against metabolic imbalances associated with the use of some oral contraceptives. Vitamin B-6 promotes iron excretion and this has been used as a rationale for treatment in iron storage diseases.

Vitamin B-6 is usually safe, at intakes up to 200 mg per day in adults. However, Vitamin B-6 can cause neurological disorders, such as loss of sensation in legs and imbalance, when taken in high doses (200 mg or more per day) over a long period of time. Vitamin B-6 toxicity can damage sensory nerves, leading to numbness in the hands and feet as well as difficulty walking. Symptoms of a pyridoxine overdose may include poor coordination, staggering, numbness, decreased sensation to touch, temperature, and vibration; and tiredness for up to six months.

Check with your doctor if any of these most common side effects persist or become bothersome:

Dry and splitting hair; gingivitis (inflammation of the gums); bleeding gums; rough, dry, scaly skin; decreased wound-healing rate; easy bruising; nosebleeds; weakened tooth enamel; swollen and painful joints; anemia; decreased ability to fight infection; possible weight gain because of slowed metabolism.

Vitamin B6 is a water-soluble compound that was discovered in the 1930s during nutrition studies on rats. The vitamin was named pyridoxine to indicate its structural homology to pyridine. Later it was shown that vitamin B6 could exist in two other, slightly different, chemical forms, termed pyridoxal and pyridoxamine. All three forms of vitamin B6 are precursors of an activated compound known as pyridoxal 5 -phosphate (PLP), which plays a vital role as the cofactor of a large number of essential enzymes in the human body.

Enzymes dependent on PLP focus a wide variety of chemical reactions mainly involving amino acids. The reactions carried out by the PLP-dependent enzymes that act on amino acids include transfer of the amino group, decarboxylation, racemization, and beta- or gamma-elimination or replacement. Such versatility arises from the ability of PLP to covalently bind the substrate, and then to act as an electrophilic catalyst, thereby stabilizing different types of carbanionic reaction intermediates.