Preliminary findings also showed a link to poorer lung function. Children of mothers who take in too little vitamin E during pregnancy may be at higher risk for asthma by age five, a new study suggests.
The finding expands on previous research conducted by the same team. That work found that two-year-old children whose moms had relatively low vitamin E intake during pregnancy were more prone to wheezing — even when they were otherwise healthy.
“This is part of a body of work that indicates that sufficient vitamin E intake is probably important,” said study lead author Dr. Graham Devereux, of the department of environmental and occupational medicine at the University of Aberdeen in Scotland.
Devereux and his team reported their findings in the September issue of the American Journal of Respiratory and Critical Care Medicine.
The authors focused on over 1,250 women who were pregnant and attending neo-natal clinics in Scotland between 1997 and 1999.
Maternal dietary intake was assessed dating back to conception, as were medical histories related to asthma, wheezing and related respiratory issues. The same information was gathered for the children of these women up until the age of five.
Maternal intake of nutrients such as vitamin C, beta-carotene, magnesium, copper, and iron during pregnancy did not seem to be correlated with an increased risk for wheezing or asthma, the team found.
However, low intake of vitamin E during pregnancy was associated with a higher risk among offspring for developing persistent asthma, beginning during the first two years of life and continuing to at least until age five.
In fact, children born to mothers rated in the bottom 20 percent for prenatal vitamin E intake were more than five times more prone to asthma as children born to mothers in the top 20 percent.
Youngsters born to mothers with relatively poor vitamin E intake during pregnancy were also at higher risk for developing persistent wheezing in their first 5 years of life, the Scottish researchers reported.
The researchers stressed that a child’s diet at age five appears to have no impact on their asthma risk.
They pointed out that fetal airways are fully developed 16 weeks following conception. That suggests that certain dietary deficiencies during pregnancy — particularly early pregnancy — may heighten risks for childhood asthma.
However, much more research is needed to confirm that low prenatal vitamin E helps cause childhood asthma, Devereux said.
For that reason, Devereux said, it is premature for women to take vitamin E supplements, at any dosage, to help ward off asthma in their offspring.
Vitamin E is abundant in many staple foods such as green leafy vegetables, whole grain cereals, vegetable oils, meat, and fish. The average adult’s daily vitamin E needs could be fully met if these foods were included in a balanced and healthy diet, Devereux said.
“It should be strongly emphasized that women should eat healthily during pregnancy and not take vitamin E supplements just because of this study,” Devereux cautioned.
Dr. Arun Jeyabalan, an assistant professor in the division of maternal fetal medicine at the University of Pittsburgh’s Magee Women’s Hospital, agreed.
“This is an important study because it is important to look at associations between nutrient intake, deficiencies, and potential pregnancy outcomes,” she said. “However, women should be very careful about supplementation. Not all vitamins in high doses are good for anybody, and further study is needed before advocating any kind of vitamin E supplementation.”