The fat-soluble vitamin A (also: retinol; precursor: beta-carotene) is particularly important for eyesight, the skin and the immune system. It regulates light and dark vision, is important for the development and maintenance of skin cells and mucous membranes and for the immune system. The precursor of this vitamin, beta-carotene, has an antioxidant effect in the body.
The recommended daily requirement is 0.8 mg for women, for men 1 mg.
In industrialized countries there is seldom a deficiency in vitamin A. In the case of a prolonged undersupply, deficiency symptoms such as dry skin and mucous membranes, weakened immune defenses, night blindness and, in extreme cases, corneal opacities occur.
Side effects of overdose
An overdose of vitamin A can occur if one consumes too much beef liver or takes too high doses of dietary supplements. This can lead to headaches and nausea. Long-term oversupply can damage the liver. An overdose of beta-carotene can lead to yellow skin discoloration. Studies show that high-dose beta-carotene supplements increase the risk of lung cancer in smokers.
Foods high in vitamin A
Vitamin A can be found particularly rich in liver, egg yolks, fish, whole milk and dairy products. Beta-carotene is contained primarily in carrots, red peppers, and spinach.