The scientists at the University Medical Centre, Rotterdam, and other institutions in the Netherlands say that consuming as little as three-quarters of the recommended daily amount of Vitamin E while pregnant can lead to a nine-fold increase the risk of a heart problem at birth.
The scientific study was case-controlled and examined possible associations between congenital heart defects (CHDs) and maternal intake of Vitamin E and retinol - retinol is the active form of Vitamin A that has previously been associated with CHDs.
Vitamin E is found naturally in numerous foods including nuts, avocado and olive oil and is important to human health - Vitamin A (retinol) has already been linked to causing harm to the development of the foetus and for this reason, consumption above 700 micrograms per day during pregnancy is advised - no such recommendations currently exist regarding safe Vitamin E levels during pregnancy but pregnant women need not be concerned by Vitamin E in foods as long as they eat a healthy, balanced diet, but should avoid taking supplements of Vitamin E.
The study involved Dutch mothers, 276 of whom had given birth to a child with a congenital heart defect (the case group) and 324 of whom had given birth to a healthy child (the control group).
The diets of both groups were compared and mothers of babies with heart defects were found to have consumed higher amounts of Vitamin E - the research has limitations in that the mothers' diets were assessed when their children were already 16 months old, which may not reflect diet around the time of conception and birth.
However despite this limitation the possible association between high Vitamin E intake and congenital heart defects is an important one which warrants further research.
The study found that though the case mothers were found to be slightly older than control mothers, there was no difference between mothers in their medical history or family history of CHDs or in their use of tobacco, alcohol or use of vitamin supplements.
It is clear say the experts that further research is needed into the important question of whether high amounts of Vitamin E in the diet during pregnancy increase the risk of congenital heart defects in newborns.
The research was conducted by Smedts, H.P.M and colleagues and was funded by a grant from the Corporate Development International and the Netherlands Heart Foundation.
The research is published in the British Journal of Obstetrics and Gynaecology.
