Measuring Vitamin A
For many nutritional vitamins and minerals there’s one easy unit of measure (normally milligrams). Vitamin A is extra difficult as a result of there are totally different types of the vitamin and totally different precursors.
Vitamin A is normally measured in micrograms (one-thousandth of a milligram) of RAE (retinol exercise equivalents). Nonetheless, vitamin labels on meals and dietary supplements record vitamin A in Worldwide Models (IU). 1 IU of retinol equals zero.three micrograms of RAE.
The Institute of Medication (IOM) has set the advisable dietary allowance (RDA) at 700 micrograms (equal to 2,333 IU) a day for girls, 900 micrograms (three,000 IU) for males. To make issues extra complicated, the Every day Worth for vitamin A on vitamin labels is 5,000 IU, nonetheless based mostly on the outdated RDA from 1968.
The IOM has set the Higher Restrict for vitamin A at three,000 micrograms (10,000 IU) a day. It usually takes long-term use of a lot larger doses to trigger scientific toxicity. Pregnant ladies, specifically, shouldn’t exceed that restrict. Some main researchers imagine that the IOM ought to decrease the Higher Restrict.