B vitamins and energy metabolism: roles, deficiencies, and supplementation effects — a review
Kennedy DO
Evidence is still building up
Summary
A narrative review covering the roles of B vitamins (B1, B2, B3, B5, B6, B7, B9, B12) in energy metabolism. Each B vitamin acts as an indispensable cofactor in mitochondrial ATP production, the TCA cycle, fatty acid β-oxidation, and amino acid metabolism. Deficiency causes neurological symptoms, dermatitis, and anemia, but additional benefit from supplementation in replete healthy individuals is limited. As water-soluble vitamins, excess is excreted in urine, making toxicity risk low at standard doses.
Key findings
- 1
B vitamins are essential cofactors in ATP production, the TCA cycle, and fatty acid β-oxidation
- 2
Deficiency manifests as neurological symptoms (B1, B12), dermatitis (B3, B7), and megaloblastic anemia (B9, B12)
- 3
Supplementation clearly improves symptoms in deficient individuals, but additional benefit in replete individuals is limited
- 4
Water solubility confers low toxicity risk at standard doses; high-dose B6 (>50 mg) has been associated with peripheral neuropathy
Related supplements
PR
Functions as a coenzyme in energy metabolism (ATP production, TCA cycle, etc.)
A balanced formula that covers the B vitamins in one product
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Last checked: 2026-06-24