Necessary evil

Otherwise considered vital for human health, vitamin A is now believed to endanger the well-being of new borns, if consumed in excess

Published: Thursday 29 February 1996

Vitamin A blights the might to (Credit: UN Photo)WHILE large doses of the synthetic counterparts of several vitamins are known to be toxic to adults, the large intake of one of these is now known to play havoc with the well-being of unborn and newborn babies.

Currently under fire is vitamin A. Found in dairy products, liver and green leafy vegetables, its deficiency results in retarded growth, lower resistance to infection, dry skin, night blindness and an eye disease called xerophthalmia.

Recently, researchers at the Boston University School of Medicine in the US found that the large intake of vitamin A supplements by pregnant women cause defects in the developing embryo. Kenneth J Rothman and his colleagues discovered that "among the babies born to women who took more than 10,000 international units (IU) of vitamin A per day in the form of supplements, about one in 57 infants had a malformation attributable to the supplement".

Currently, the recommended daily allowance of vitamin A for pregnant women in the US is.8,000 IU. "Larger doses of it can cause a characteristic set of birth defects," declare the researchers. Apparently, the brain And the spinal cord are the worst affected. While the brain suffers from impaired development, the spinal cord fails to get encapsulated by the vertebral column due to its incomplete formation. In technical parlance, the former abnormality is called anencephaly and the latter as spina bifida.

Apart from causing these birth defects, vitamin A has now been held responsible for weakening the effect of the life-saving vaccines being administered to infants. A team of scientists at the John Hopkins University in the US, has issued a warning against the practice of administering a massive dose of vitamin A to infants along with regular immunisation programmes in the developing countries. The team found that vitamin A "suppressed any live virus given as a vaccine" in the presence of maternal antibodies. The mother's antibodies, which help the infant fight infections, remain in the child's blood stream for nine months to one year after birth. However, the mother's protection conferred on a child with not so well-defined an immune system, fights against the friendly live virus given in vaccine form if large vitamin A doses are also delivered.

The practice of large-scale administration of vitamin A to children, along with vaccines against measles, polio, tetanus and other deadly diseases, started in some countries of Asia and Africa at the behest of some international organisations, which pressurised health agencies in these countries. Whether the reasons behind this campaign was protecting malnourished babies from eye diseases, or improving the market for the vitamin, remains open for debate.

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