Can high doses of vitamin A cause birth defects?
Vitamin A is crucial for normal fetal growth and development. However, too much of it may cause birth defects. A 1995 study found that women who took more than 10,000 IUs (international units) of vitamin A daily in the first two months of pregnancy doubled their risk of having a baby with birth defects (10). The birth defects were similar to those seen in isotretinoin-exposed babies. The FDAs current daily value (DV) for vitamin A is 5,000 IUs (11). Other studies have suggested that doses less than 25,000 IU probably do not cause birth defects, but the lowest dose that can cause birth defects is unknown (6). The body makes its own vitamin A, when needed, from vitamin A precursors, such as beta carotene, which is found in yellow and green vegetables and some multivitamins. This form of the vitamin is believed to be completely safe during pregnancy. However, much of the vitamin A we consume is the preformed vitamin which, in excessive amounts, can cause birth defects. Preformed vitamin A