Mediterranean eating habits help European children fight genetic obesity risk

New research reveals that a Mediterranean diet can help counteract genetic predisposition to obesity in children, highlighting the diet’s potential for early-life obesity prevention across Europe.

Study: Mediterranean diet and obesity polygenic risk interaction on adiposity in European children: The IDEFICS/I.Family Study. Image Credit: Viktor Kochetkov / Shutterstock.com

In a recent study published in the journal Pediatric Obesity, researchers examined how genetic factors and adherence to the Mediterranean diet interact to predict obesity risk among a cohort of European youth.

The genetics of obesity

Obesity is a multifactorial disease that arises due to a combination of modifiable environmental factors like diet and non-modifiable genetic traits. Several obesity-related single-nucleotide polymorphisms (SNPs) have been identified, and these SNPs are collectively used to estimate polygenic risk scores (PRS) and other genetic scores for disease risk.

The Mediterranean diet primarily comprises whole and minimally processed foods, including fruits, vegetables, whole grains, beans, nuts, olive oil, and fish. Greater adherence to the Mediterranean diet has been associated with improved health outcomes across all age groups. Among children, high MD adherence has been shown to support growth, cardiometabolic health, and reduce the risk of chronic diseases.

The current study's researchers investigated the role of the Mediterranean diet in modulating the genetic risk of developing obesity among a cohort of 1,982 European children between two and 16 years of age. Adherence to the Mediterranean diet was based on the Mediterranean Diet Score (MDS), whereas a PRS for high body mass index (BMI) (BMI-PRS) was used to predict each individual’s risk of developing obesity.

Study findings

Equal representation from both males and females was observed throughout the study period, with most of the study participants from medium to high socioeconomic households. Sustained intermediate adherence to the Mediterranean diet was observed throughout the six-month follow-up period.

Greater MDS was significantly associated with lower adiposity measurements, particularly waist circumference (WC), at baseline. At the first follow-up visit, which was conducted two years after baseline measurements were obtained, higher MDS was associated with lower BMI and WC. Nevertheless, no significant associations were observed between adiposity measurements at the six-year follow-up visit, nor in the longitudinal analysis.

Higher BMI-PRS predicted higher BMI and WC at baseline, with the relationship between high BMI-PRS and high BMI further strengthened by the presence of a high MDS.

Two years later, higher MDS weakened BMI-PRS, thus indicating that individuals at a greater genetic risk of developing obesity were less likely to have gained weight when they reported higher adherence to the Mediterranean diet. These findings suggest that certain biological factors may interact differently with diet and genetics during early childhood.

Irrespective of genetic predisposition to obesity, increased vegetable and legume consumption correlated with a lower risk of obesity at the six-year follow-up visit. Importantly, these results should be interpreted with caution, as dietary patterns were self-reported, and vegetable and legume consumption may have been over-reported.

Ensuring high MDS in children at an early age may remain the best strategy to prevent children from developing obesity at an early age, where obesity is known to persist across age groups, from childhood to adulthood.”

Strengths and limitations

Repeated phenotyping of the pediatric study cohort is a key strength, as it facilitated the longitudinal analysis of how genetics and diet interact to affect obesity risk. Despite the potential for recall bias, the standardized dietary assessment method allowed the study participants’ caretakers to provide detailed information on their children’s dietary patterns.

A major limitation of the study design is that it relies on self-reported data for both food intake patterns and physical activity levels. By utilizing BMI-PRS, which is based on data obtained from genome-wide association studies (GWAS), other and less common genetic variants may not be considered in the analysis, thus necessitating larger genetic studies to identify possible correlations between these hereditary factors and obesity risk among individuals regularly consuming a Mediterranean diet.

Although the study cohort was large enough to be representative, the lack of complete data from all study participants is another notable limitation of this study.