A mother’s diet long before conception may permanently alter the functioning of her child’s genes, with implications for lifelong health.

A new study published in Nature Communications on Tuesday describes an investigation by the London-based MRC International Nutrition Group, who followed more than 2,000 women in the northwest African country of Gambia. There, the researchers recruited 84 women who had conceived at the peak of the rainy season, along with 83 women who had conceived during the height of the dry season.

By comparing the content of nutrients found in the mother’s bloodstream with blood and hair samples from children born during the study, the researchers found that maternal diet had significantly influenced epigenetic changes in the child’s DNA. Among such possible modifications to one’s genetic functioning is the “tagging” — and therefore silencing — of gene regions by methyl groups.

Mother's Diet Influences Children's Genetic Functioning, Before Conception
London-based researchers find that a mother's diet can influence her children's genetic functioning, and therefore health, long before conception. Similar animal studies in the emerging field of epigenetics have shown the same with regard to paternal diet. Photo courtesy of Felicia Webb/press release. MRC

Although children inherit their genes from their parents, environmental factors such as maternal — and paternal — diet have been shown to change the functioning of those genes. Past study of epigenetics in animals found that maternal diet can change the coloring of a mouse’s offspring through a permanent alteration of DNA methylation. Now, study leader Branwen Hennig says the effects have been observed in humans, too.

"Our results represent the first demonstration in humans that a mother's nutritional well-being at the time of conception can change how her child's genes will be interpreted, with a life-long impact," Hennig said in a statement.

Yet those effects might be a bit harder to discern in humans, an animal slightly more complex than the mouse. The researchers found that infants born during the rainy season carried “consistently higher” rates of methyl groups within the six genes on which they focused. They also found strong associations between homocysteine and cysteine and maternal diet, suggesting the two compounds played some sort of role.

Andrew Prentice, a professor of international nutrition, says the methyl groups may be strongly susceptible to nutrition problems. “Our on-going research is yielding strong indications that the methylation machinery can be disrupted by nutrient deficiencies and that this can lead to disease,” he said. “Our ultimate goal is to define an optimal diet for mothers-to-be that would prevent defects in the methylation process. Pre-conceptional folic acid is already used to prevent defects in embryos.”

The study findings, he said, indicate a need for a “cocktail of nutrients,” which might come from either dietary staples or supplements. Already, women in poverty-stricken regions such as Gambia receive folic acid supplements shown effective in preventing embryonic defects.

Source: Dominguez-Salas M, Sophia E, Baker MS, et al. Maternal nutrition at conception modulates DNA methylation of human metastable epialleles. Nature Communications. 2014.