PYRIDOXINE (Vitamin B6)

 Main Characteristics

• It is a water-soluble vitamin and is present in the following forms: pyridoxine, pyridoxal, pyridoxamine, pyridoxal 5-phosphate, among other forms.

• It acts as a cofactor for approximately 70 enzyme systems, such as in the metabolism of amino acids and proteins.

• It acts in the conversion of glycogen into glucose to provide energy to muscle tissue.

• Vitamin B6 deficiency is very rare, as it is present in the composition of several foods and in their fortification, but the losses of this vitamin during food processing and cooking are high.

 

Main Functions and Mechanisms of Action

• Regulation of amino acid metabolism and energy production: it participates in the transamination of amino acids and ketoacids, to be used as metabolic fuel and in the synthesis of phospholipids, and also promotes the cleavage of liver and muscle glycogen.

• Prevention of Atherosclerosis and Cardiovascular Diseases: Vitamin B6, B12 and B9 participate in the metabolism of homocysteine.

• Production of hemoglobin: acts as a cofactor of an enzyme important for the production of the heme molecule.

• Action on the Central Nervous System: important in the synthesis of GABA and other neurotransmitters, improving symptoms of depression, PMS, anxiety, etc., in addition to acting on cognitive development.

• Acts on the metabolism of serotonin and dopamine.

• Prevention of Breast Cancer: Pyridoxine has an effect on the modulation of steroid hormones, participates in the metabolism of carbons and in the maintenance of the immune system.

 

Bioavailability

• The absorption of vitamins in general has a daily absorption limit. It seems that the B vitamins in general do not have this daily limit, since high doses are well absorbed, most of the vitamin B6 ingested is absorbed and taken to the liver to play its role in metabolism.

• It is worth noting that if the intestinal flora is in trouble, the bioavailability of vitamin B6 will be impaired and absorption will be reduced.

Possible interactions

• Drugs such as diuretics, contraceptives, tetracyclines, and isoniazid can deplete vitamin B6 from the body.

Interaction between nutrients

 • Supplementation with 25 mg/day of pyridoxine for ten days is enough to reduce folate levels by 27%, but without reducing homocysteine.

• High protein intake can reduce pyridoxine status indicators.

 

Scientific evidence regarding the effectiveness of supplementation

• Since vitamin B6 also acts in the synthesis of prostaglandins, there are claims that it regulates blood pressure, heart function, and pain levels.

• Vitamin B6 is recommended for the treatment of carpal tunnel syndrome. In some cases, symptoms were relieved by administering doses above 100 mg of vitamin B6.

• Vitamin B6 supplements, sold in combination with folic acid, have been shown to have a significant effect on reducing plasma levels of homocysteine ​​(an amino acid metabolite linked to an increased risk of atherosclerosis).

Risks of overdose

• There are no reports of toxicity, but when ingested in high doses, it can lead to neurotoxicity and skin lesions, as well as tingling in the feet and hands and difficulty walking.

• Individuals with chronic renal failure undergoing parenteral nutrition and receiving multivitamin supplementation may present peripheral neuropathy and involuntary movements due to elevated plasma levels of pyridoxine.