As a precautionary measure to prevent birth defects, FDA has issued several recommendations for women of childbearing age regarding excessive consumption of foods, including dietary supplements, containing one form of vitamin A.

The vitamin form of concern is called preformed vitamin A. It is found in animal products, primarily liver, and is also sometimes added to fortified foods such as breakfast cereals and dietary supplements. The products' ingredient listings should note the addition as, for example, retinyl palmitate and retinyl acetate. Women need to limit their intakes from these sources to about 100 percent of the Daily Value (5,000 IU).

On the other hand, beta carotene, a substance found naturally in plants and which the body converts to vitamin A, is considerably less toxic. Women of childbearing age are advised to choose fortified foods that contain vitamin A in the form of beta carotene rather than preformed vitamin A, whenever possible. The vitamin A in fruits and vegetables is naturally in the form of beta carotene, and high intakes of vitamin A from these sources is generally not of concern.

Vitamin A is an essential nutrient and, as with all nutrients, the good health of women throughout childbearing years, including pregnancy, depends on consuming appropriate amounts.

FDA offered these recommendations in response to a New England Journal of Medicine article on the possible relationship between some types of birth defects and the consumption of vitamin A at levels at or above 10,000 IU. A relationship between vitamin A intakes and birth defects has been known for some time, but the level of vitamin A-associated birth defects in earlier studies was much higher.