Which vitamins are considered water-soluble?

• A. Vitamin C only
• B. B vitamins and C vitamins
• C. A, D, E, K
• D. Vitamin B12 and Biotin

Answer: (B)

Water-soluble vitamins are the B vitamins and vitamin C. They dissolve in water, are not stored in large amounts in the body's tissues, and excess is excreted in urine. Because they aren’t stored, daily intake is important, and deficiency can develop relatively quickly if intake is low. In contrast, fat-soluble vitamins A, D, E, and K are stored in fat and liver and don’t require daily consumption. The full group of water-soluble vitamins includes all B vitamins (thiamin, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folate, and cobalamin) plus vitamin C, which is why the option listing B vitamins and C vitamins is correct. The other options either point to fat-soluble vitamins or omit portions of the water-soluble group.