New research shows that following a Mediterranean diet while pregnant can prevent childhood obesity, with gene-related effects potentially playing a role in long-term health outcomes.
Study: Effects of Mediterranean diet during pregnancy on the onset of overweight or obesity in the offspring: a randomized trial. Image Credit: Alex Maryna / Shutterstock.com
In a recent study published in The International Journal of Obesity, researchers investigate the effects of nutritional counseling promoting a Mediterranean diet (MD) while pregnant on the likelihood of children born to these mothers being obese or overweight by two years of age.
The impact of the maternal diet on childhood obesity
The rise in childhood obesity has become a significant public health issue worldwide and, as a result, necessitates the implementation of strategies to prevent health problems in later life. Early life, including pregnancy, is a key period for preventing obesity, as a mother’s diet can influence a child's future health.
The MD, rich in fiber, antioxidants, and healthy fats, is known for its benefits in preventing excess weight during adulthood. During pregnancy, the MD may protect children from developing obesity through its potential effects on the regulation of certain genes.
However, there remains a lack of evidence on whether following MD during pregnancy could prevent overweight and obesity during early childhood. Although some observational studies have been conducted, experimental research is needed to understand these associations.
About the study
The MD during Pregnancy (PREMEDI) trial was designed to examine whether women who followed the MD while pregnant could prevent obesity or overweight in their children by age two. A total of 104 pregnant women were randomly assigned to either receive standard care only or standard care in addition to personalized MD counseling.
Women assigned to the MD group attended three diet counseling sessions during pregnancy. MD recommendations included eating more vegetables, fruits, whole grains, fish, and legumes, using olive oil, and avoiding processed foods.
The primary study outcome was the percentage of children who were obese or overweight when they were two years old. Secondary outcomes included maternal adherence to the MD and weight gain throughout the pregnancy.
The researchers also measured changes in gene expression, focusing on the leptin gene, which is linked to weight regulation. Follow-up assessments of the children were conducted every few months until their second birthday. Statistical analyses were performed to compare outcomes between the two groups.
Study findings
Following the MD during pregnancy reduced the likelihood of children being overweight or obese by the age of two. In the MD group, no child was obese, and 6% were overweight, compared to 8% and 22% of children who were obese and overweight in the control group, respectively.
The absolute difference in risk, defined as the average risk in the control group subtracted from the average risk in the treatment group, was significant. To this end, the number needed to treat (NNT) was four, thus indicating that, for every four women who followed the MD, one case of child obesity or overweight was prevented.
Maternal weight gain during pregnancy was similar in both groups, demonstrating that the MD did not affect weight gain. Children born to mothers in the MD group had slightly higher birth weights as compared to those in the control group.
Further analysis showed that the MD was associated with higher methylation at the promoter of the leptin gene. Thus, the MD may influence gene expression related to weight regulation in offspring.
Conclusions
The study findings highlight the importance of maternal diet in preventing childhood obesity, as following the MD during pregnancy appears to reduce the risk of obesity or overweight in children.
A key strength of the current study is the experimental design, which provides robust evidence as compared to previous observational studies with mixed results. The researchers also explored potential underlying mechanisms, including changes to the leptin gene, which may explain how MD affects obesity risk.
However, notable limitations of the current study include the small sample size and the genetic analysis being limited to a few samples, which could affect the generalizability of the results. Additional limitations include the inability to blind participants and the lack of other MD adherence biomarkers.
Future research should include more extensive trials with more diverse populations and explore additional biomarkers of MD adherence. Additional studies are also needed to determine the long-term effects of following the MD while pregnant on obesity and other health outcomes in later childhood and adulthood.
Journal reference:
- Coppola, S., Paparo, L., Bedogni, G., et al. (2024). Effects of Mediterranean diet during pregnancy on the onset of overweight or obesity in the offspring: a randomized trial. International Journal of Obesity. doi:10.1038/s41366-024-01626-z