Vitamin and C dissolve into the water when a vegetable is boiled, and are then lost when the water is discarded. The body's stores for different vitamins vary widely; vitamins A, D, and B are stored in significant amounts, mainly in the liver, and an adult's diet may be deficient in vitamins A and D for many months and B in some cases for years, before developing a deficiency condition. However, vitamin B (niacin and niacinamide) is not stored in significant amounts, so stores may last only a couple of weeks. For vitamin C, the first symptoms of scurvy in experimental
Vitamin A can be represented as two connected retinyl groups, which are used in the body to contribute to vitamin A levels. Alpha-carotene and gamma-carotene also have a single retinyl group, which give them some vitamin activity. None of the other carotenes have vitamin activity. The carotenoid beta-cryptoxanthin possesses an ionone group and has vitamin activity in humans. Vitamin A can be found in two principal forms in foods: Vitamin A deficiency is estimated to affect approximately one third of children under the age of five around the world. It is estimated to claim the lives of 670,000 children under five annually.