NEW YORK (Reuters Health) – A diet high in vitamin E during early pregnancy may increase the risk of congenital heart defects in offspring, new research indicates. The risk appears to be highest when high dietary vitamin E intake is combined with vitamin E supplements.
According to a Dutch research team, excessive oxidative stress may contribute to the development of congenital heart defects. Because high levels of vitamins E and A are believed to exert pro-oxidant effects, they theorize that excessive intakes of either one around the time of conception could affect embryogenesis.
Led by Dr. R. P. M. Steegers-Theunissen at University Medical Center, Rotterdam, the investigators conducted a case-control study among participants of the Dutch HAVEN (Heart Defects, Vascular Status, Genetic Factors and Nutrition) study. As reported in the February issue of BJOG: An International Journal of Obstetrics and Gynaecology, their analysis included 276 mothers of children with heart defects and 324 control mothers.
When their infants were 16 months old, the mothers completed food frequency questionnaires for the 4 weeks prior to the study. According to the authors, dietary patterns during this time are comparable to the preconception period.
Compared with the lowest quartile of vitamin E intake from diet alone (4.0-10.6 mg/day), the odds ratio for congenital heart defects for the highest quartile (14.9-33.8 mg/day) was 1.7 (p for trend = 0.01).
Moreover, dietary vitamin E intake above 12.6 mg/day plus the use of a supplement containing vitamin E increased the risk 5- to 9-fold (p = 0.008 for trend). The effect was not modified by folic acid supplementation.
By contrast, high intake of retinol