Vitamin B6

Pyridoxine

Vitamin B6 (pyridoxine) is a water-soluble vitamin that includes three forms, pyridine derivatives: pyridoxine (pyridoxol), pyridoxal and pridoxamine. It is found naturally in many foods, such as grains, liver, milk, eggs and green vegetables. Pyridoxal 5′-phosphate is the active form and the most common measure of vitamin B6 concentration in the blood. This active form is a coenzyme that helps break down proteins, carbohydrates, fats, and maintains a normal level of homocysteine. Pyridoxine is a vitamin that is very important to support the immune function of the body, but it is also important for the proper work and function of the central nervous system.

Daily needs: The recommended daily intake for vitamin B6 for men aged 14 to 50 is 1.3 mg/day, while for men over 50 it is 1.7 mg/day. The recommended daily intake for women aged 14 to 18 is 1.2 mg/day, for women aged 19 to 50 is 1.3 mg/day and for women over 50 is 1.5 mg/day. Daily needs for vitamin B6 during pregnancy and lactation increase, so these needs amount to 1.9 mg/day.

Recommended Dietary Allowances (RDAs) for Vitamin B6

Age	Male	Female	Pregnancy	Lactation
0-6 months	0.1 mg*	0.1 mg*
7-12 months	0.3 mg*	0.3 mg*
1-3 years	0.5 mg	0.5 mg
4-8 years	0.6 mg	0.6 mg
9-13 years	1.0 mg	1.0 mg
14-18 years	1.3 mg	1.2 mg	1.9 mg	2.0 mg
19-50 years	1.3 mg	1.3 mg	1.9 mg	2.0 mg
51+ years	1.7 mg	1.5 mg

Vitamin B6 metabolism: Pyridoxal and its analogues are easily absorbed from the intestine. Phosphorylated derivatives are first translated into the free form, and then the absorption process takes place. In the cytoplasm of the cells of the intestinal tract, liver and other organs, all three forms of vitamin B6 bind to the enzyme pyridoxal-kinase and such a reaction leads to the synthesis of the corresponding phosphate esters. Phosphate esters bind to various apoenzymes in the cell. Vitamin B6 is eliminated through the urine.

Pyridoxine is very important in disease prevention. In the form of supplements, it is most often recommended in the treatment of nausea caused by pregnancy, but such use takes place under the supervision of a doctor.

Vitamin B6 deficiency: Vitamin B6 deficiency is associated with a deficiency of other water-soluble vitamins in the body, especially vitamin B12 and folic acid. Mild deficiency is not symptomatic, but larger deficits can lead to the following symptoms: microcytic anemia, depression, confusion, weakened immune system, inflammatory skin conditions. Certain diseases can increase the risk of vitamin B6 deficiency, namely: kidney failure, autoimmune diseases of the gastrointestinal tract, rheumatoid arthritis, alcoholism. Chemotherapy and tuberculostatics lead to hypovitaminosis B6. The tuberculostatic isoniazid binds to pyridoxine and a hydrazone compound is formed, which inhibits pyridoxine kinase. Penicillamine, which is used in the treatment of Wilson’s disease, also exhibits an antagonistic effect.

A mutation in the methylenetetrahydrofolate reductase gene occurs in most elderly patients with memory loss. This is the reason why in people suffering from Alzheimer’s disease there is an increase in the concentration of homocysteine, which further worsens the symptoms of this disease. Also, other factors that can lead to hyperhomocysteinemia are aging and lack of B complex vitamins, primarily vitamin B12, vitamin B9 (folic acid) and vitamin B6. In patients with a diagnosis of Parkinson’s disease, who were introduced to levodopa as a pharmacological therapy, it is recommended to take vitamins B6, B9 (folic acid) and B12 in addition to this therapy, in order to alleviate hyperhomocysteinemia and other clinical complications.

Vitamin B6 excess: There is very little possibility of an overdose of vitamin B6, because it is a vitamin that is soluble in water, so the excess of unused vitamin is excreted through urine. A toxic reaction can occur if vitamin B6 is given in high doses for a long period of time. Symptoms of overdose are: nausea, vomiting, neuropathy of the feet and hands, ataxia (loss of control over body movements).

Vitamin B6

References