Vitamin B6 (pyridoxine) is a water-soluble vitamin. It is needed for more than 100 enzymes involved in protein metabolism and is essential for red blood cell metabolism. The nervous and immune systems need vitamin B6 to function efficiently (Ann NY Acad Sci 1990; 585:404).
A deficiency of vitamin B6, folic acid, or vitamin B12 may increase your level of homocysteine. There is evidence that an elevated homocysteine level is an independent risk factor for heart disease and stroke. Some small trials have shown that these homocysteine reducing vitamins reduce the rate of restenosis (blood vessel narrowing) after angioplasty and slow the progression of atherosclerosis. Vitamin B6 is also needed for the synthesis of neurotransmitters such as serotonin and dopamine. These neurotransmitters are required for normal nerve cell communication. Research is now underway to investigate the relationship between vitamin B6 neurologic conditions such as seizures, chronic pain, depression, headache, and Parkinson's disease (Ann NY Acad Sci 1990; 585:250).
Vitamin B6 is found in a wide variety of foods including fortified cereals, beans, meat, poultry, fish, and some fruits and vegetables. Too much vitamin B6 can result in nerve damage to the arms and legs. This neuropathy is usually related to high intake of vitamin B6 from supplements and is reversible when supplementation is stopped. (Institute of Medicine, 1998).