PYRIDOXINE Summary
Pyridoxine cannot be manufactured by humans and is obtained exclusively from the diet. Following activation to pyridoxyl-5-phosphate (P5P), pyridoxine serves as a cofactor in over 100 enzymes in carbohydrate, lipid, and amino acid metabolism. In particular, PLP is the cofactor for the enzymes that synthesize GABA and serotonin, both of which are neurotransmitters with key inhibitory roles. Pyridoxine/PLP is also involved in myelin and hemoglobin synthesis, as well as gene expression. Deficiency is generally found in individuals with highly-restricted diets and/or substantial gastrointestinal disease. Symptoms can include weakness, fatigue, depression, seizures, peripheral neuropathy, vomiting, anemia, and cardiovascular disease including stroke. Pyridoxine is sometimes recommended for a very long list of neurological and other conditions, including hyper-excitable states such as ADD/ADHD, anxiety, insomnia, and irritability. Side effects are rare at usual doses used in supplementation.