Vitamin B6 is also called Pyridoxine and is a vitamin that plays an important role in the breakdown and use of energy sources, production of [[red blood cells and antibodies, and normal functioning of the nervous system.
Sources of Vitamin B6
Pyridoxine (pir" i dox' een) is a water soluble B vitamin found in many foodstuffs, but in highest concentrations in meat, legumes and nuts. Pyridoxine actually represents a family of related compounds including pyridoxine, pyridoxal, pyridoxamine and their phosphates, which are the active coenzyme forms of vitamin B6.
Mechanism of action of Vitamin B6
Pyridoxine acts as a cofactor in many enzyme systems, particularly in amino acid metabolism and heme synthesis.
RDA intake of Vitamin B6
The recommended dietary allowance for pyridoxine is 1.3 to 2.0 mg for adults, a level that is well within that provided in typical American diets. Pyridoxine deficiency is rare, but can occur with severe malnutrition and chronic alcoholism.
Deficiency of Vitamin B6
Symptoms of deficiency include weakness, fatigue, dermatitis, cheilosis and anemia. Certain medications including isoniazid, L-dopa, penicillamine and cycloserine interact with vitamin B6 and can cause deficiency. For that reason, these drugs are often given with pyridoxine supplementation (10 to 25 mg daily).
Dosage and administration for Vitamin B6
Pyridoxine is available over-the-counter in multiple forms and concentrations and is included in virtually all multivitamin preparations, typically in concentrations of 2 to 3 mg. High doses of pyridoxine (50 to 500 mg daily) have been recommended to treat carpal tunnel syndrome, schizophrenia, autism and diabetes, but the efficacy in these conditions is not proven.
Side effects of Vitamin B6
Oral forms of pyridoxine (below 100 mg daily) have not been associated with adverse events, ALT elevations or hepatotoxicity. Prolonged use of high doses has been linked to sensory neuropathy and to occasional symptoms of nausea, gastrointestinal upset and dermatitis, but not to liver injury.