The most common question that pregnant women ask me is "My obstetrician says that it is very dangerous for me to take vitamin A while I'm pregnant. As an expert in nutrition, what is your opinion?"
No doubt, there is a lot of fear and confusion on this topic. So let's get right down to the truth of the matter. As usual, the truth is to be found in the middle of two opposite points of view. One point of view is that pregnant women should avoid taking any vitamin A. The other point of view is that pregnant women do not need to be concerned at all with their vitamin A consumption because the risks are minimal.
So let's clarify the issue so you can make the most informed choice for yourself and your baby:
In 1995, the prestigious New England Journal of Medicine published a study that showed strong evidence that approximately 1.7% of pregnant women in the U.S. consuming greater than 10,000 International Units (IUs) of vitamin A (retinol) per day during the first 7 weeks of their pregnancy gave birth to children afflicted with some form of birth defect. This was one out of every 57 women. This created a wave of fear in obstetricians and their pregnant patients that continues to this day.
The good news about this study is that it alerted doctors to strongly caution their pregnant patients that consuming over 10,000 IUs of vitamin A per day for the first 7 weeks of her pregnancy can be risky. To my way of thinking this should also hold true for women of childbearing age who are actively trying to become pregnant. Women who are given very high dosages of vitamin A for acne treatments should avoid becoming pregnant until their blood levels of vitamin A are well within the normal range.
The bad news about the effects the NEJM vitamin A study is that it made far too many obstetricians and obstetrical nurses overly cautious, even paranoid, about women taking anyform of vitamin A, even supplements containing beta-carotene. Obviously no pregnant woman wants to put her developing baby at risk, so when their obstetrician tells them to avoid taking all vitamin A they listen.
The other side of the truth is that developing babies need somevitamin A. Vitamin A deficiency can cause fetal and infant growth retardation. It is well known that plant scientists have been trying to perfect modified strains of rice to contain beta-carotene (orange in color) for third world countries. Why? To help prevent the large amount of infants born blind every year because their mother's bodies did not have enough vitamin A to donate an adequate amount to their developing eyes!
The World Health Organization (WHO) estimates that between 250,000 and 500,000 children are born blind every year. WHO also estimates that 13.8 million children have some degree of visual loss related to vitamin A deficiency.
Carotenes and carotenoids are natural pigments that give colored fruits and vegetables their bright colors. Carrots are a good example because their orange color is reflective of an abundance of carotenoids and carotenes. There are over 600 carotenoids/carotenes and less than 50 seem to be able to be converted into vitamin A. This conversion is essential, however, because the human vision is dependent upon these pigments.
The conversion of carotenes to vitamin A depends upon a number of factors including adequate zinc, vitamin C, protein status, bile salts, pancreatic enzymes and optimal thyroid gland health. So women with inadequate levels of these necessary co-factors have more difficulty converting high pigment foods into vitamin A.
One International Unit (IU) of vitamin A (retinol) does not equal one IU of beta-carotene because only between 40%-60% of beta-carotene is absorbed and converted into vitamin A. Also, the absorption of beta-carotene is self-limiting. This means that beyond a healthy level, the more you take the less you absorb. Beta-carotene taken in supplement form absorbs better than beta-carotene from foods. Betacarotene is safe and necessary.
On average, a healthy daily intake of vitamin A for pregnant women is approx. 4000 IUs. This means that if you have been told by your obstetrician to avoid taking all vitamin A and you are receiving less than about 8000 IUs of carotenes from your prenatal vitamin and your diet combined, there is increased risk that your child may suffer some degree of visual loss or growth retardation. The risk of pregnant women receiving too little vitamin A is just as unacceptable as too much vitamin A.
As previously stated, the truth tends to be found right in the middle of the two opposite points of view. Too much vitamin A brings a small but significant risk of birth defects. Too little vitamin A brings a risk of visual loss or growth retardation.
So what do you do when you become pregnant?
Here are some guidelines:
(1) To be on the safe side, it is best to avoid prenatal vitamins that contain any of the retinol form of vitamin A.
(2) Try to make sure that your daily intake of vitamin A does not exceed 6000 IUs during the first 2 months of your pregnancy.
(3) Avoid eating foods very high in the retinol form of vitamin A on a daily basis, especially beef liver (43,900 IUs/3.5 oz serving) and calves liver (22,500 IUs/3.5 oz. serving).
(4) Make sure that your prenatal vitamin contains at least 3500 IUs of betacarotene.
(5) Try to obtain 4000-5000 IUs of carotenes and carotenoids from your diet. You can do this by eating lots of colored vegetables like carrots and green leafy vegetables.
(6) Eat brightly colored fruits.
(7) If you cannot eat enough colored vegetables, find a good tasting vegetable powder that can provide you with 4000-5000 IUs of these essential precursors to vitamin A.
(8) Do your best to take this middle ground and try not to worry.
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