Children whose malnourished mothers took vitamin A during pregnancy had stronger lungs throughout childhood, with the benefits measurable well past the age of 9, researchers reported on Wednesday.
Lung capacity was about 3 percent higher in children whose mothers took vitamin A compared to those whose mothers received a placebo, the study of 1,371 children in Nepal showed.
"Early interventions involving vitamin A supplementation in communities where undernutrition is highly prevalent may have long-lasting consequences for lung health," Dr. William Checkley of Johns Hopkins University in Baltimore and colleagues wrote in the New England Journal of Medicine.
When mothers were given beta carotene, a precursor of vitamin A, their children did not score higher on the lung capacity test.
The benefits are believed to have come from treatment during pregnancy because all the children received regular vitamin A supplements after birth.
The researchers said an estimated 190 million preschool-age children and 19 million pregnant women have vitamin A deficiency worldwide. The shortfall can cause health problems during pregnancy and early development, including lung problems.
The study piggybacked off a test done in the 1990s in which 44,646 women in 30 village developments in Nepal were given weekly supplements before, during and after pregnancy.
The older test included 2,055 newborns, and researchers from Johns Hopkins decided to track those children down to test their lung capacity.
"The magnitude of the effect observed in this study is slightly greater than that associated with preventing exposure to parental smoking in school-aged children," the researchers wrote.
The original study found that supplementation with either vitamin A or beta carotene reduced by 44 percent the risk of a woman dying because of complications of pregnancy, compared to women who got placebo capsules. The supplements, however, had no effect on infant mortality.