What type of vitamin is niacin?

• A. Vitamin A
• B. Vitamin B
• C. Vitamin C
• D. Vitamin D

Answer: (B)

Niacin is a member of the B vitamin family, specifically vitamin B3. It’s a water-soluble vitamin that serves as a coenzyme in energy metabolism, forming NAD and NADP required for many redox reactions. Because it’s part of the B vitamins, niacin is essential for turning food into usable energy. Deficiency causes pellagra (dermatitis, diarrhea, dementia), while excess intake can cause flushing when taken as nicotinic acid. You’ll find niacin in animal products, fortified grains, and some nuts and seeds. This places it squarely in the B vitamin group rather than fat-soluble vitamins like A, C, or D.