B Vitamins
topic
The B vitamins are eight water-soluble vitamins — B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin) — collectively essential for energy metabolism (converting macronutrients to ATP), DNA synthesis and repair, red blood cell production, nervous system function, and one-carbon metabolism (methylation reactions governing gene expression, neurotransmitter synthesis, and homocysteine regulation). B12 is found almost exclusively in animal products, making it the critical supplementation priority for those on plant-based diets.
Role
B vitamin deficiencies — particularly B12, folate, and B6 — are among the most consequential for cognitive function, cardiovascular health, and mood regulation, yet remain drastically under-evaluated in populations at risk. B12 deficiency in vegans and vegetarians is entirely preventable and yet produces severe, irreversible neurological damage if allowed to progress undetected — a tragedy of nutritional neglect that affects an estimated 52% of long-term vegans who are not supplementing. Elevated homocysteine (produced by B9 and B12 insufficiency) is an independent cardiovascular and cognitive decline risk factor affecting a substantial portion of the population whose B vitamin status has never been measured.