Vitamin A, a fat-soluble vitamin, which is responsible for the development of the most perplexing and startling parts of a baby’s body especially eyes. According to the National Health Service (NHS-UK), vitamin-A increases immunity and skin cell production for baby. The study by Checkley, et al. also proved that it also helps to develop the millions of alveoli in baby’s lungs which allow oxygen to transfer into the blood, and carbon dioxide to back out.
Generally, there are two forms of Vitamin-A available in our diet
- Preformed Vitamin A (Retinol, retinyl ester) – available in animal sources, including meat, fish, dairy products, and eggs.
- Provitamin A carotenoids (Beta-carotene, alpha-carotene, and beta-cryptoxanthin) – These are mainly found in plant sources (fruits and vegetables).
After consuming those sources, our body converts both preformed vitamin-A and provitamin-A into retinal and retinoic acid intracellularly to receive the utility of vitamin-A. On the other hand, other pigments like lycopene and zeaxanthin have no vitamin-A activity.
It is well established in the health society that we need to balance the amount of vitamin-A in pregnancy. Because, too little amount of vitamin-A can cause maternal infection, maternal or even perinatal mortality. But there are also risks of getting the too high amount of vitamin-A which can lead to birth defect to your unborn child.
According to the USDA recommendation, the daily recommended allowance (RDA) of vitamin-A for a normal adult person maximum 10,000 IU of preformed vitamin A from all kind of sources including supplements, animal sources, and fortified foods. But, the RDA for the person aged 0-18 years is lower than that.
But, is really consuming high vitamin-A can cause birth defect? Or what are the sources of vitamin-A causes birth defects? There are some synthetic derivatives of vitamin-A which can act as a powerful teratogen. Therefore the question may arise if vitamin-A is teratogenic or not, and what is the reasonable level of consuming vitamin-A which can act as a teratogen for pregnant women.
The possible link between vitamin-A and birth defects first published in New England Journal of Medicine by Rothman, et al. in 1995. This study found that vitamin-A can show its teratogenicity if we consume a high amount of preformed vitamin-A by diet. Besides being simple epidemiological study, scientifically the cause and effect relationship was weak. And it started a lot of argument between scientists too. And because of being published in a very high profile journal, it survived and lead us to a dark dimension of vitamin-A and teratogenicity.
In 1998, Wiegand, et al. summarized previous studies on vitamin-A supplementation to check the teratogenic effect on human. In this study, they have shown that dose of 30,000 IU per day can be considered as non-teratogenic for human, based on the results found in the cynomolgus monkey.
In that year, another study was also published in Reproductive Toxicology by Miller, et al.which showed very irrefutably that vitamin A itself had no teratogenicity. But this study found that blood levels of retinoids of women taking 30000IU per day of preformed vitamin-A and the pregnant women during the first trimester who delivered healthy babies are comparable. And high doses of β-carotene perform neither teratogenicity nor vitamin A toxicity.
In 1999, Mastroiacovo, et al. published a study which persuades us even better. There was a subgroup of women, who has been supplemented more than 50000IU per day throughout the pregnancy. This study showed us that taking of supplementation during pregnancy does not increase birth defect, even high dose like 50000IU per day.
But, as it has stated earlier that, vitamin-A is a fat-soluble vitamin. That means it can be stored in the liver and it has a toxic effect also, which is called hypervitaminosis-A. Hypervitaminosis-A can occur if a high amount of preformed vitamin-A is consumed by a human in a very short period of time. If this type of consumption continues for a longer period, then it may turn in chronic toxicity.
I would like to conclude this article by giving a general idea of the diet custom in Bangladesh. If you can prove any item, that is good for health in our country, our people will consume it as much as possible, that turns bad for hyper-consuming. For that reason, I would like to say to everyone that, definitely vitamin-A is good for you and child and an essential supplement for those malnourished pregnant women. But be sure you are balancing it in your diet.
Md Tanvir Islam, currently working as “Research Nutritionist” at “The JiVitA Project- a research project implemented by “Johns Hopkins University” in Bangladesh. He can be reached at firstname.lastname@example.org
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