Mediterranean diet during pregnancy protective against paediatric obesity?

The risk of overweight or obesity is lower among offspring of mothers who received nutritional counselling promoting the Mediterranean diet (MD) during pregnancy on top of standard obstetrical and gynaecological care (CT) as opposed to kids whose mums only received CT, the PREMEDI study has shown.

At 24 months, kids of mums in the MD arm were less likely to be overweight or obese compared with their contemporaries in the CT arm (6 percent vs 30 percent; absolute risk difference, −24 percent; p=0.003). [Int J Obes (Lond) 2025;49:101-108]

“[This suggests that] MD during pregnancy could be an effective strategy for preventing paediatric overweight or obesity at 24 months,” the researchers said.

According to the investigators, this effect may be mediated in part by an epigenetic modulation of leptin expression, as evidenced by the higher mean methylation rate of the leptin gene in cord blood mononuclear cells in the MD vs the CT arm (30.4 percent vs 16.9 percent; p<0.0001).

“[T]he leptin gene is the principal gene associated with obesity … The observed increase in methylation at the leptin gene promoter region suggests that the expression level of this obesity-related gene may be lower in women following MD,” the investigators explained.

Counselling also improves MD adherence

In the study, a MedDiet score of ≥9 signified adequate MD adherence. Based on this metric, baseline MD adherence was low in the MD and CT arms (7 and 6.5).

However, the score improved during the trial. The mean MedDiet score difference in the MD vs CT arms was 0.7 (Bonferroni-corrected p=0.08) at the first trimester, 3 (Bonferroni-corrected p<0.0001) at the second, and 4.1 (Bonferroni-corrected p<0.0001) at the third. Of note, the mean MedDiet score in the MD arm was ≥9 by the second trimester, implying excellent MD adherence, they said.

“[The] findings suggest that personalized nutritional counselling could be effective in improving MD adherence during pregnancy,” said the investigators.

A major public health concern

The current paediatric obesity epidemic is a major public health concern that warrants effective preventive strategies to curb the disease burden. [https://www.who.int/ mediacentre/factsheets/fs311/en, accessed 12 February 2025]

“The initial stages of life provide a window of opportunity to prevent the occurrence of overweight or obesity and attain long-term health outcomes. The future disease susceptibility can be influenced by nutritional exposures during this critical period of life,” said the researchers.

Focusing on maternal diet during pregnancy may be a feasible approach for preventing overweight and obesity later in life, they said. The MD is considered a healthy diet pattern that has been linked to a lower risk of noncommunicable diseases, including obesity. [Rev Endocr Metab Disord 2020;21:315-327]

A potentially cost-saving preventive strategy

In PREMEDI, 104 women (median age 32 years, mean gestational age 39 weeks) in their first trimester of pregnancy were randomized 1:1 to CT with or without nutritional counselling promoting MD. Of these, 97 completed the study.

CT comprised standard-of-care recommendations, including energy intake, physical activity, optimal weight gain during pregnancy based on pre-pregnancy weight, and hygiene rules for food-related illnesses.

The MD nutritional counselling promoted the use of extra virgin olive oil as main cooking fat (at least 4 tbsp per day); consuming 2 L of water per day, two servings of vegetables per day, three servings each of fruit, wholegrain cereals, and skimmed dairy products per day, and three servings each of legumes, fish, and nuts and seeds per week; reducing red and processed meat intake; and avoiding fruit juices, refined grains, and ultra-processed foods including processed baked goods, pre-sliced bread, precooked meals, and soft drinks.

Despite the small study sample, lack of blinding and assessment of other MD adherence biomarkers, and limited samples used in the DNA methylation analysis, the results support the role of MD during pregnancy as a safe, effective, and potentially cost-saving strategy against the paediatric obesity pandemic, said the researchers.