Vitamin B-6 is a water-soluble vitamin in the B-complex vitamin group. The B vitamins are used by the body as coenzymes, which make biochemical reactions possible. B-6 consists of three substances, pyridoxine, pyridoxal phosphate, and pyridoxamine. All three forms can be utilized by the human body, but only pyridoxine is officially designated as B-6.
Vitamin B-6 enables many enzymatic reactions in the body. The brain and central nervous system require B-6 as a catalyst for the formation of their chemical transmitters. B-6 is needed for the conversion of carbohydrates into energy, and of tryptophane into nicotinic acid (vitamin B-3). It also plays a role in the formation of red blood cells and the metabolism of amino acids.
If taken in large doses, B-6 can cause varied neurological symptoms such as numbness in the hands and feet, and a general loss in sensory perception. It is generally considered nontoxic when taken in doses up to 100 mg daily. Because B-6 is needed to process protein, an increased dietary intake of protein necessitates increased consumption of B-6. The RDI recommendation is 2 mg of vitamin B-6 for every 100 grams of dietary protein.