Effects of Mediterranean diet during pregnancy on the onset of overweight or obesity in the offspring: a randomized trial

BACKGROUND/OBJECTIVES: The PREMEDI study was designed to assess the efficacy of nutritional counseling aimed at promoting Mediterranean Diet (MD) during pregnancy on the incidence of overweight or obesity at 24 months in the offspring. METHODS: PREMEDI was a parallel-arm randomized-controlled trial. 104 women in their first trimester of pregnancy were randomly assigned in a 1:1 ratio to standard obstetrical and gynecological care alone (CT) or with nutritional counseling promoting MD. Women in the MD arm received 3 counseling sessions (one per trimester). The main outcome was the proportion of offspring with overweight or obesity at 24 months. Maternal MD-adherence and gestational weight gain were evaluated. Epigenetic modulation of metabolic pathways in the offspring was analyzed in cord blood. RESULTS: Five women in the MD arm and two in the CT arm were lost to follow-up (97 completed). At 24 months, children of MD mothers were less likely to have overweight/obesity than those of CT mothers (6% vs. 30%; absolute risk difference = −24%, 95% CI −38% to −9%, p = 0.003; number needed to treat 4, 95% CI 2 to 12; per-protocol). MD adherence increased significantly more in the MD arm; gestational weight gain was similar between arms. Mean (SD) leptin gene promoter methylation in cord blood was 30.4 (1.02)% in the MD arm vs. 16.9 (2.99)% in the CT arm (p < 0.0001). CONCLUSIONS: MD during pregnancy could be an effective strategy for preventing pediatric overweight or obesity at 24 months, potentially involving epigenetic modification of leptin expression.