Vitamin B6 (PLP)

Vitamin B6 is the primary vitamin for processing amino acids used in production of proteins and is also needed to make a variety of hormones including serotonin, melatonin, and dopamine.

Vitamin B6 is a group of the three related compounds pyridoxine, pyridoxal, and pyridoxamine, and their phosphorylated derivatives pyridoxine 5'-phosphate, pyridoxal 5'-phosphate, and pyridoxamine 5'-phosphate. Although all of these compounds should technically be referred to as vitamin B6, the term vitamin B6 is usually used interchangeably with just one of the vitamers, pyridoxine. Vitamin B6 plays a role in a variety of biochemical reactions in the human body including the metabolism of amino acids and glycogen, the synthesis of nucleic acids, hemoglobin, sphingomyelin and other sphingolipids, and the biosynthesis of neurotransmitters including serotonin, dopamine, norepinephrine, and gamma-aminobutyric acid (GABA).

While vitamin B6 deficiency is not common in most developed regions of the world, it still occurs. Typical symptoms of vitamin B6 deficiency are microcytic, hypochromic anemia, seizures, dermatitis, confusion, and depression. Vitamin B6 deficiencies in infants are usually demonstrated by electroencephalogram abnormalities and seizures, while in adults B6 deficiency symptoms include chapped and cracked lips, tongue inflammation, stomotitis, anemia, irritability, confusion, and depression. Unfortunately, these symptoms are not limited only to vitamin B6 deficiencies. Vitamin B6 deficiency usually is a result of a malabsorption syndrome, uremia, cancer, cirrhosis, alcoholism, old age, and pregnancy.

When taken with folic acid and vitamin B12, vitamin B6 can support healthy homocysteine levels. Abnormal levels of homocysteine have been linked to heart disease and stroke as well as to osteoporosis and Alzheimer's disease.

Vitamin B6 can be found naturally in a number of foods including red meat, poultry, fish, eggs, white potatoes and other vegetable, non-citrus fruits, cereals, and soy-based meat substitutes.

Dosage and Administration

The optimum intake of supplemental vitamin B6 is not known. Typical doses of pyridoxine used for nutritional supplementation range from 2 to 20 milligrams/day or more.