- Pyridoxine, commonly referred to as vitamin B6, is a water-soluble vitamin that plays a vital role in a wide range of physiological functions, particularly in protein metabolism, neurotransmitter synthesis, immune function, and red blood cell formation.
- It exists in several forms—pyridoxine, pyridoxal, and pyridoxamine—which are all converted in the body to the active coenzyme form pyridoxal 5′-phosphate (PLP). PLP is involved in more than 100 enzymatic reactions, especially those associated with amino acid metabolism, including transamination, decarboxylation, and deamination processes that are essential for energy production and the synthesis of important biomolecules.
- One of pyridoxine’s most critical functions is its role in neurotransmitter synthesis, including serotonin, dopamine, gamma-aminobutyric acid (GABA), norepinephrine, and histamine. This makes it essential for normal brain development and function, as well as the regulation of mood and behavior. It is also necessary for the conversion of the amino acid tryptophan into niacin (vitamin B3), which links vitamin B6 to broader aspects of nutrient metabolism. In addition, PLP plays a role in hemoglobin synthesis and helps regulate homocysteine levels in the blood, high levels of which are associated with an increased risk of cardiovascular disease.
- Dietary sources of vitamin B6 include poultry, fish, liver, potatoes, bananas, fortified cereals, and legumes. Because it is water-soluble, pyridoxine is not stored in large quantities in the body, requiring regular dietary intake to maintain adequate levels. However, it is more stable than some other B vitamins and relatively resilient to cooking losses.
- Deficiency in vitamin B6, while not common in healthy populations, can occur due to factors such as poor dietary intake, chronic alcoholism, malabsorption syndromes, certain genetic disorders, or the use of medications that interfere with B6 metabolism (e.g., isoniazid, hydralazine, and oral contraceptives). Symptoms of deficiency can include irritability, depression, confusion, peripheral neuropathy, weakened immune function, and in severe cases, seizures. In infants, deficiency may result in irritability and convulsions.
- Pyridoxine is also used therapeutically in certain clinical conditions. It is often prescribed to treat premenstrual syndrome (PMS), morning sickness in pregnancy, carpal tunnel syndrome, and certain types of anemia. However, while vitamin B6 is generally safe at recommended doses, long-term use of high-dose supplements (typically over 100–200 mg/day) has been associated with sensory neuropathy, a condition characterized by numbness, tingling, and difficulty walking.
