When it comes to vitamin A and pregnancy, smack in the middle of the road is where you want to be.
The recent early release of a Boston University School of Medicine study showed that women who consistently take a small overdose of vitamin A are at increased risk for having a child with birth defects such as cleft lip, cleft palate, water on the brain and heart malformations.
The study and its researchers do not suggest that pregnant women should give up their prenatal vitamins or avoid foods high in vitamin A, according to Neva Cochran, a Dallas dietitian who is spokeswoman for the American Dietetic Association.
She says: "During pregnancy, the right amount of vitamin A is needed for the baby's developing bones, teeth, skin and eyes."
So it's important to strike a healthy balance.
The birth-defects problem arose in women who took 10,000 I.U. or more of pre-formed vitamin A daily for an extended period of time.
You're unlikely to get that much from food, even in combination with a prenatal vitamin.
Vitamin A is a fat-soluble vitamin, so any excess you consume is stored in the liver. That means even women of childbearing age who are not pregnant, but could be, should be careful not to overdose on pre-formed vitamin A.
Also, be aware that, although most prenatal and multivitamin
supplements contain safe levels of vitamin A, some supplements sold in health food stores contain vitamin A at levels as high as 25,000 I.U. per capsule. Be sure to read the label on any supplement and check the quantity.
As you can see from the chart, liver is high in vitamin A. However, a small serving will "average out" as part of a balanced DTC diet, according to Ms. Cochran. "You wouldn't want to eat it daily, but occasionally it will fit."
Among people returning to more old-fashioned remedies, there is a retro-trend toward the daily dose of cod liver oil. One measuring tablespoonful is above the danger zone. Like liver, an occasional spoonful would average out. But unlike liver, the tendency is to take a spoonful daily, which would quickly accumulate to toxic levels.
If you're pregnant or planning to be, take your multivitamin. It also contains the B vitamin, folic acid, in large-enough quantities to prevent some other birth defects.
Also, start seeing an obstetrician before you get pregnant. Be sure to discuss all supplements, prescription medicines and over-the-counter products, even if they are "natural" products. Too much of a good thing can hurt you and your baby.
One more reassuring note: Most of us get the bulk of our vitamin A indirectly, from plant sources such as orange and dark green leafy vegetables. Plants contain beta carotene, which can become vitamin A in your body. Mountains of research have shown that beta carotene is safe at high levels. So feel free to eat all the fruits and vegetables you want. Also, check your vitamin supplements to see if some of their vitamin A occurs as beta carotene, which gives you an even wider margin of safety.
Colleen Pierre, a registered dietitian, is the nutrition consultant at the Union Memorial Sports Medicine Center and Vanderhorst & Associates in Baltimore.
The Recommended Dietary Allowance (RDA) established by the National Research Council is 5,000 International Units (I.U.) of vitamin A daily. Most prenatal vitamins provide 4,000 to 5,000 I.U. per tablet. Pre-formed vitamin A occurs only in the fat of animal products. Common sources of pre-formed vitamin A :
The yolk of one large egg 300 I.U
8 ounces milk* 500 I.U.
1 ounce cheese* 350-300 I.U.
8 ounces yogurt* 100-150 I.U.
1 ounce fortified cereal 750-1,500 I.U.
3 ounces liver 15,000-30,000 I.U.
1 tablespoon cod liver oil 13,600 I.U.
* The vitamin A occurs in the fat in dairy products. Fat-free yogurt and cheese contain no vitamin A. Although skim milk contains no fat, it is fortified with vitamin A at a level equal to whole milk.