Source: FDA U.S Food and Drug Administration
Your body uses vitamins for a variety of biological processes, including growth,
digestion, and nerve function. There are 13 vitamins that the body absolutely
needs: vitamins A, C, D, E, K, and the B vitamins (thiamine, riboflavin, niacin,
pantothenic acid, biotin, vitamin B-6, vitamin B-12 and folate). AAFP cites two
categories of vitamins.
- Water-soluble vitamins are easily absorbed by the body,
which doesn't store large amounts. The kidneys remove those vitamins that are
- Fat-soluble vitamins are absorbed into the body with the
use of bile acids, which are fluids used to absorb fat. The body stores these
for use as needed.