Vitamin A is a fat soluble vitamin which is stored in the liver. Found in animal foods and converted from beta-carotene in plant foods, vitamin A health benefits include: healthy vision, gene expression, reproduction, embryonic development, red blood cell production, and immune function.
Deficiency is rare in Canada, but common in developing countries due to malnutrition. It causes night blindness, dry eyes and skin, and impaired growth.
Drugs that deplete vitamin A include: cholestyramine, colestipol, mineral oil, and neomycin.
Vitamin A supplements from beta carotene should be avoided by those at risk of lung cancer (smokers) since a number of large scale studies have shown an increase in lung cancer rates when smokers consumer beta carotene in a supplement.
Those with liver toxicity (alcoholics, liver disease) should also avoid beat carotene supplements since beta carotene is stored in the liver.
Doses greater than 10,000 IU daily should be avoided by pregnant women due to the risk of birth defects. Supplements of vitamin A beyond what is provided in a multivitamin are not recommended due to risk of toxicity. To avoid this risk, choose a multivitamin that contains beta-carotene, which is converted to vitamin A in the liver, but is not associated with health risks. Eating a lot of beta-carotene from foods can make your skin look yellow, because beta-carotene (which is a yellow-orange pigment)is stored in the cells under our skin. This may look odd but it is not harmful to your health.
Foods that provide vitamin A health benefits include: liver, dairy products, and oily fish (Beta-carotene is found in orange and green vegetables and fruit).