List four factors that affect how much of a vitamin is available to the body

List four factors that affect how much of a vitamin is available to the body. 1. How much of the vitamin can be absorbed. This can be affected by the composition of the diet. For example, the absorption of fat-soluble vitamins is reduced if the amount of fat in the diet is very low. The presence of other substances in the diet that interfere with absorption are alsoimportant. For example, antithiamin factors may destroy the thiamin in some foods. 2. How much of a vitamin can be absorbed is also affect by digestive processes. For example, if the amount of acid in the stomach is low it may prevent some vitamins from being released from foods. 3. Once inside the body the availability of transport proteins needed to transport vitamins in the blood affect how much is available to the body 4. The amount of a vitamin that is available is also affected by conditions in the body, such as the ability to convert a provitamin to its active form.