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VITAMIN A AND BIRTH DEFECTS
The consumption of vitamin A at levels at or above 10,000 IU (200% of the Daily Value, or DV), or 3000 Retinol equivalents (REs), and some types of birth defects has raised serious public health concerns. A relationship between vitamin A intakes and birth defects has been known for some time, but the level of vitamin A associated with earlier studies was much higher than the levels indicated by the new study.
As a precautionary measure, FDA has several recommendations for women of childbearing age relative to consuming foods containing vitamin A, including dietary supplements.
First, the form of vitamin A that is of concern is preformed vitamin A. Preformed vitamin A is found in animal products, primarily liver, and also may be added to fortified foods such as breakfast cereals and dietary supplements (examples of preformed vitamin A include retinyl palmitate and retinyl acetate, which are found in the products' ingredient listings). Women need to limit their intakes to about 100% of the DV for preformed vitamin A for these sources from this nutrient.
On the other hand, beta-carotene is a substance found naturally in plants, and it can be converted to vitamin A in the body. It is considerably less toxic than the preformed vitamin A. Therefore, women of childbearing age are advised to choose fortified foods that contain vitamin A in the form of beta-carotene rather than pre-formed 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 generally are not of concern.
Finally, vitamin A is an essential nutrient. The good health of women throughout childbearing years, including pregnancy, is dependent on the consumption of needed amounts of this nutrient. Taking too little vitamin A can result in adverse effects just as taking in too much can. The key is in finding the "right amount" through carefully reading product nutrition labeling.
Craig Winkel, MD
Dr. Winkel is Past Professor and Chair of the Department of Obstetrics and Gynecology at Georgetown University in Washington, DC.
Date Published: 2000-09-25
7800 Wolf Trail Cove, Germantown, TN 38138
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