VitaminABedarf

Vitamin A Bedarf, or Vitamin A requirement, refers to the daily amount of vitamin A and its provitamin carotenoids needed to maintain normal health in an average person. Nutrition guidelines typically express this need as retinol activity equivalents (RAE) or international units (IU). For adults, commonly cited figures are about 900 mcg RAE per day for men and 700 mcg RAE per day for women, with higher needs during pregnancy and lactation. Requirements vary by age, sex, and physiological status, and many countries provide reference tables to guide intake.

Dietary sources include preformed vitamin A (retinol) from liver, fish oils, dairy products, and eggs, as well as provitamin A carotenoids such as beta-carotene from colorful fruits and vegetables. Absorption and conversion depend on dietary fat and individual factors, and carotenoids contribute to vitamin A status with varying efficiency.

Deficiency can lead to night blindness, xerophthalmia, impaired immune function, and growth or developmental issues in children, particularly in populations with limited dietary diversity. On the other hand, excessive intake of preformed vitamin A can cause toxicity, with a tolerable upper intake level around 3000 mcg RAE per day for adults; chronic high intake may harm the liver and, in pregnancy, raise risk of birth defects. Excessive supplementation with retinol poses greater risk than consuming carotenoids from foods, which generally have a lower toxicity potential.

Assessment of vitamin A status is complex; plasma retinol reflects deficiency only at advanced stages and can be influenced by infection and inflammation. Diet, supplement use, and health status together determine overall Vitamin A Bedarf.