Why do we need vitamins?

There are 13 essential vitamins: A, C, D, E, K and eight B vitamins. Many act as helpers for enzymes, allowing reactions such as releasing energy from food, building DNA and making red blood cells. Fat-soluble vitamins (A, D, E and K) are stored in body fat and the liver, while water-soluble ones (C and the Bs) must be topped up more regularly. Deficiencies cause specific diseases: scurvy from lack of vitamin C, rickets from lack of vitamin D and beriberi from lack of thiamine (B1). Most people can get enough from a varied diet, though some groups are advised to supplement vitamin D.