Vitamin A tablets in a blister pack. Vitamin A (retinol) plays an important role in maintaining healthy skin and mucous membranes, as well as in growth, reproduction and night vision. It is found in liver and dairy products and can also be produced by the body from beta carotene found in vegetables and fruit. Deficiencies in vitamin A can lead to slow growth and night blindness. Excessive doses can be toxic, causing aches and pains and in some extreme cases liver failure and death.