What are the cofactors involved in Vitamin B6 (Pyridoxine) metabolism?

From the Guidelines

Vitamin B6 metabolism is heavily reliant on cofactors such as magnesium, zinc, and riboflavin to function properly, with magnesium being the most crucial for the conversion of pyridoxine to its active form, pyridoxal-5-phosphate (PLP) 1. As outlined in the study on selected B vitamins and their possible link to the aetiology of age-related sarcopenia, vitamin B6 plays a significant role in amino acid metabolism as the cofactor pyridoxal 5′-phosphate (PLP) 1. The activation of vitamin B6 to its active form, PLP, is essential for its involvement in various physiological processes, including the synthesis of haeme, neurotransmitters, purines, hormones, and fatty acids 1. Key points to consider in B6 metabolism include:

• Magnesium is necessary for the conversion of pyridoxine to PLP
• Zinc supports B6 metabolism and enzyme function
• Riboflavin is required for the formation of the active P5P form
• Adequate ATP levels are necessary for the phosphorylation process that activates B6 Given the importance of these cofactors, supplementing with them alongside B6 can improve outcomes for individuals with B6 metabolism issues, with typical daily recommendations including 300-400mg of magnesium, 15-30mg of zinc, and 25-50mg of riboflavin 1. The interplay of these cofactors in enzymatic reactions affects various bodily processes, including neurotransmitter production, amino acid metabolism, and homocysteine regulation, highlighting the need for a balanced approach to supporting B6 metabolism 1.

From the Research

Cofactors in B6 Metabolism

• Vitamin B6 is involved in over 100 biochemical reactions, including amino acid and homocysteine metabolism, glucose and lipid metabolism, neurotransmitter production, and DNA/RNA synthesis 2.
• It is a coenzyme that participates in the metabolism of carbohydrates, lipids, amino acids, and nucleic acids, and is also involved in cellular signaling 3.
• Vitamin B6 can act as a modulator of gene expression and has antioxidant properties, with the ability to lower advanced glycation end products (AGE) levels 3.
• The vitamin is essential for various bodily functions, including energy-yielding metabolism, DNA synthesis, oxygen transport, and neuronal functions, making it critical for brain and muscular function 4.

Biochemical Reactions and Pathways

• Vitamin B6 is involved in the metabolism of homocysteine, an amino acid associated with an increased risk of cardiovascular disease and other chronic diseases 2.
• It participates in the synthesis of neurotransmitters, such as serotonin and dopamine, which are essential for mood regulation and other psychological processes 2.
• Vitamin B6 is also involved in the metabolism of glucose and lipids, making it an important factor in energy production and storage 3.

Dietary Requirements and Recommendations

• The recommended dietary allowance (RDA) for vitamin B6 is 1.5-2.2 mg/day, although individual requirements may vary depending on factors such as age, sex, and protein intake 5.
• The average requirement (AR) for vitamin B6 intake is 1.2 mg/day for adult females and 1.3 mg/day for adult males, with corresponding recommended intakes (RIs) of 1.4 mg/day and 1.6 mg/day, respectively 6.
• Pregnant and lactating women have higher vitamin B6 requirements, with ARs of 1.3-1.5 mg/day and RIs of 1.5-1.8 mg/day 6.