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Higher adherence to the Mediterranean diet is associated with a modest reduction in the risk of obesity-related cancers, according to research conducted by the European Prospective Investigation Into Cancer and Nutrition (EPIC) study. The study found a 6% lower cancer risk among participants with high Mediterranean diet adherence, independent of adiposity measures.
In the study, “Adherence to the Mediterranean Diet and Obesity-Linked Cancer Risk in EPIC,” published in JAMA Network Open, outcomes focused on the incidence of obesity-related cancers classified under the 2015 International Agency for Research on Cancer criteria.
Between 1992 and 2000, EPIC enrolled 521,324 participants aged 35 to 70 years across 23 centers in 10 European countries. This prospective cohort analysis included 450,111 participants after exclusions for baseline cancer diagnoses, missing data, extreme energy intake ratios, and Greek cohort data.
Researchers assessed dietary intake through validated country-specific questionnaires and calculated adherence using a 9-point Mediterranean Diet Score (MedDiet), categorizing participants into low (0–3), medium (4–6), or high (7–9) adherence groups.
Multivariable Cox proportional hazards regression models adjusted for potential confounders, including smoking, physical activity, education, alcohol intake, height, total energy intake, and type 2 diabetes. Mediation analyses examined the roles of body mass index (BMI) and waist-to-hip ratio (WHR).
During a median follow-up of 14.9 years, 4.9% of participants developed obesity-related cancers. High MedDiet adherence was associated with a lower risk of these cancers (hazard ratio [HR], 0.94) compared with low adherence. Medium adherence showed a similar though statistically insignificant inverse association. No significant mediation by BMI or WHR was observed.
Site-specific analyses revealed inverse associations between high Mediterranean diet adherence and colorectal (HR, 0.92), hepatocellular (HR, 0.52), and kidney (HR, 0.67) cancer risks. Medium adherence was associated with lower esophageal cancer risk (HR, 0.66). No significant associations emerged for hormone-related cancers in women.
Results remained consistent across sensitivity analyses, including models excluding the first two years of follow-up and variations of the Mediterranean diet score without the alcohol component. Stratified analyses indicated stronger inverse associations among smokers and men.
Researchers concluded that higher adherence to the MedDiet may significantly reduce obesity-related cancer risks through mechanisms unrelated to adiposity. Further research is necessary to explore underlying biological pathways, including inflammation, insulin sensitivity, and gut microbiota.
While not part of this EPIC study, it is plausible that the lower cancer risk associated with higher MedDiet adherence could partly reflect reduced consumption of highly or ultra-processed foods rather than any positive health effects of the MedDiet itself. Individuals with high MedDiet adherence consume more fruits, vegetables, whole grains, and fish. Highly processed foods are not part of the MedDiet index (i.e., eating more processed foods would lower MedDiet adherence).
Many recent studies, including several from EPIC, have consistently reported a positive association between higher processed food consumption and increased risk of various cancers. As MedDiet adherence inversely correlates with cancer risk, while processed food consumption exhibits the opposite trend, it could suggest that MedDiet benefits partly stem from the absence of these types of processed food products.
Another note for future research is the category of obesity-related cancers. The current study finds these inverse and adverse associations persist after adjusting for adiposity measures (body mass index, waist-to-hip ratio). Given the persistent associations after adiposity adjustment and emerging data on ultra-processed foods, future research could explore whether some obesity-related cancers are also processed-food-related cancers.
More information:
Inmaculada Aguilera-Buenosvinos et al, Adherence to the Mediterranean Diet and Obesity-Linked Cancer Risk in EPIC, JAMA Network Open (2025). DOI: 10.1001/jamanetworkopen.2024.61031
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EPIC study highlights Mediterranean diet impact on obesity-linked cancer risk (2025, February 26)
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