B-3 is which vitamin?

• A. Niacin
• B. Thiamin
• C. Riboflavin
• D. Biotin

Answer: (A)

B-3 refers to niacin, a vitamin essential for energy production. It forms the coenzymes NAD and NADP, which carry electrons during many metabolic reactions, enabling the breakdown of carbohydrates, fats, and proteins into usable energy. The body can obtain niacin from foods like meat, fish, and fortified grains and can also be made from the amino acid tryptophan when protein intake is adequate. Niacin deficiency leads to pellagra, historically described by dermatitis, diarrhea, and dementia. Excess niacin can cause flushing and other side effects at high doses, though it’s also used in controlled doses for certain conditions. The other listed vitamins are different members of the B-vitamin family with distinct roles, so B-3 is best identified as niacin.