B6vitamiinia

B6 vitamin, also known as vitamin B6, refers to a group of chemically related compounds including pyridoxine, pyridoxal and pyridoxamine, and their phosphate esters. The biologically active form is pyridoxal 5'-phosphate (PLP), which serves as a coenzyme in many enzymatic reactions. Together with other B vitamins, B6 participates in numerous metabolic processes and helps the body convert food into energy.

The main role of PLP-dependent enzymes is in amino acid metabolism. They catalyze transamination, decarboxylation, deamination, racemization and related reactions that are essential for building and breaking down amino acids. Vitamin B6 is also involved in the synthesis of neurotransmitters (such as GABA, serotonin, dopamine and norepinephrine), the production of heme for hemoglobin, the metabolism of sphingolipids, and the regulation of glycogen breakdown in the liver. It supports immune function and participates in the conversion of tryptophan to niacin and to melatonin.

Dietary intake and sources: Adults generally require about 1.3–2.0 mg per day, with variations by age and sex. The tolerable upper intake level from supplements and fortified foods is commonly set at 100 mg per day to avoid adverse effects. Rich sources include fish, poultry and other lean meats, potatoes, bananas, chickpeas, fortified cereals, and certain seeds and nuts. Cooking can reduce vitamin B6 content in foods.

Deficiency and toxicity: B6 deficiency can cause sideroblastic anemia, dermatitis, glossitis, cheilosis, depression and confusion, with more severe symptoms in chronic malabsorption or alcoholism. Prolonged high intake from supplements can lead to sensory neuropathy and ataxia. Deficiency is relatively rare in balanced diets but may occur in alcohol dependence or certain medical conditions.