Vitamin A is essential vitamin and is part of the fat-soluble vitamin family, together with vitamin D, E and K. These vitamins can only be absorbed with fatty foods in the gut.
All fat-soluble vitamins can be stored in the body and vitamin A is stored in the liver. This also means these vitamins can be overdosed. Eating a normal an overdose is unlikely. Vitamin overdoses mostly come from excessive supplement intake or excessive consumption of liver.
Vitamin A is mainly involved in the process of vision, the immune system and growth. A deficiency mostly begins with night blindness and dark adaption trouble.
The adequate amount for men is 1000μg and for female 800μg.
Vitamin A is mostly found in liver. In vegetables there is the provitamin beta carotene and this can be transformed to vitamin A.