A new study conducted by researchers from the London School of Hygiene & Tropical Medicine, published in Nature Communications, has found that maternal diet around the time of conception can influence certain properties of the child’s DNA. This could have lifelong implications.

The researchers that conducted this study weren't looking at the actual DNA sequences of the children; they wanted to see whether the diet of the mother was capable of causing epigenetic changes. Epigenetics refers to changes in gene expression that occur without alterations in the DNA sequence itself.

One example of epigenetic modification is DNA methylation, which involves the addition of methyl groups to certain bits of DNA. Methyl groups can be obtained from the diet by eating certain foods, for example those containing choline or particular vitamins such as B6 and B12.

It was demonstrated previously that maternal diet prior to conception can induce epigenetic changes in the offspring of mice, but the same had not been investigated in humans prior to this study.

Scientists chose to study pregnant women in rural Gambia because populations here are dependent on foods that they have grown themselves and therefore their diets are different between the dry and rainy seasons. 84 women that conceived at the peak of the rainy season and 83 women that conceived at the peak of the dry season participated in the study.

The team took blood samples from the mothers in order to compare differences in nutrition; in particular they wanted to look at the levels of substances that can donate methyl groups, and therefore possibly influence DNA methylation. When they later investigated the DNA of the children they found that those conceived during the rainy season had higher rates of methylation in all of the genes studied when compared with those conceived during the dry season. They found that these changes were associated with maternal nutrient levels; in particular two amino acids called cysteine and homocysteine. They also found that increased maternal body mass index was associated with lower rates of infant DNA methylation.

It’s important to note that while associations were made between maternal diet and infant DNA methylation, this study did not investigate the consequences that this may have on the children. Although this initial study involved a small number of participants, the team believe that the data is important and hope to progress the work with larger, more in-depth studies.