Daily requirement for vitamin A

The requirement for vitamin A can be considered as those amounts which allow certain defend states of nutriture to exist.

Because the absorption efficiency of preformed vitamin in foods is equal to a greater than 90 percent, the dietary requirement is 10 percent higher than the requirement for absorbed vitamin A.

The US recommended Daily Allowance (RDA) of vitamin A for adults is 5000 IU (1000 retinol equivalents).

Main dietary sources of vitamin A are the carotenoids from fruits and vegetables. Rich dietary sources of retinol (preformed vitamin A) include dairy products, eggs and organ meats.

About 100 g of carrots or any of a large variety of green leafy vegetables can meet the daily requirement of vitamin A.

Some carotenoids (found in deep-yellow and dark green vegetables) can be converted to vitamin A during digestion. In the US diet, approximately half of the vitamin A activity is derived from B-carotene and other carotenoids. It is not essential to meet the daily basis requirement on a daily basis because the liver can store about 50 day’s supply of vitamin A.

Excess of vitamin A can cause defects in the fetal bones and central nervous system. Rarely should adult doses exceeding 25,000 IU daily be taken unless a deficiency is especially severe.
Daily requirement for vitamin A