Why should B vitamins be taken together?

B vitamins work in the body as an interconnected system of enzymatic cofactors. Each of them participates in the metabolism of carbohydrates, fats, and proteins, in the functioning of the nervous system, as well as in energy production cycles (Krebs cycle, β-oxidation of fatty acids, methionine cycle, etc.).

When we take only one vitamin from this group (for example, B6 or B12), we stimulate certain biochemical reactions that require the involvement of other B vitamins.

For example:

• B6 (pyridoxine) activates the transamination enzymes of amino acids. But these reactions also depend on the presence of B2 (riboflavin) and B3 (niacin), which are needed for the functioning of redox enzymes.
• B12 (cobalamin) is involved in the metabolism of folates (B9) and the conversion of homocysteine to methionine. A deficiency of B9 or B6 disrupts the normal functioning of this cycle.
• B1 (thiamine) is needed for the decarboxylation of carbohydrates, but this reaction also requires B2, B3, and B5 (pantothenic acid).

If one vitamin is consumed in excess, it can accelerate the depletion of others, as the entire complex of biochemical pathways begins to work more actively, "pulling" neighboring cofactors. As a result:

• the relative deficiency of the other B vitamins is intensified;
• symptoms of imbalance may appear (fatigue, irritability, insomnia, deterioration of skin or nervous system, even with the intake of "one beneficial" vitamin).

That is why in nutrition science and clinical practice, it is recommended to use a B-complex, where all B vitamins are present in balanced doses. This supports the holistic functioning of enzymatic systems and prevents the depletion of individual components.