Photo Source: Ella Olsson
A recent study published in JAMA Network Open sheds light on the link between diet and cancer risk, revealing that those who follow the Mediterranean diet may face a modestly lower risk of obesity-related cancers.
The study is conducted by the European Prospective Investigation Into Cancer and Nutrition (EPIC), the study analysed data from over 450,000 participants across ten European countries.
Study Overview and Findings
The EPIC study, which tracked 521,324 participants between 1992 and 2000, focused its final analysis on 450,111 individuals after adjusting for various exclusions.
Researchers assessed participants’ adherence to the Mediterranean diet using a 9-point MedDiet Score and found that those with high adherence (scores 7-9) had a 6% lower risk of obesity-related cancers compared to those with low adherence (scores 0-3).
Crucially, this reduction in cancer risk was independent of weight-related measures such as body mass index (BMI) and waist-to-hip ratio (WHR), pointing to the diet’s direct role in cancer prevention.
Cancer-Specific Risk Reductions
When analysing individual cancer types, the EPIC study revealed that high adherence to the Mediterranean diet was linked to notable reductions in specific obesity-related cancers. The findings suggest that the diet may play a key role in reducing the risk of certain cancers associated with excess weight.
- Colorectal cancer: 8% lower risk (HR, 0.92)
- Hepatocellular (liver) cancer: 48% lower risk (HR, 0.52)
- Kidney cancer: 33% lower risk (HR, 0.67)
Meanwhile, medium adherence (scores 4-6) was linked to a lower risk of oesophageal cancer (HR, 0.66). However, no significant associations were observed for hormone-related cancers in women.
Adjusting for Confounding Factors
The researchers meticulously adjusted for a variety of confounding factors, including smoking, physical activity, education, alcohol intake, height, total energy intake, and type 2 diabetes.
Importantly, BMI and WHR did not significantly mediate the associations, supporting the idea that the Mediterranean diet’s cancer-protective effects are not merely weight-related. The strongest protective effects were observed among men and smokers, suggesting that certain populations may experience greater benefits from adhering to the Mediterranean diet.
Potential Explanations and Future Research
Researchers have suggested several biological mechanisms that could explain the Mediterranean diet’s cancer-protective effects, including:
- Reduced inflammation
- Improved insulin sensitivity
- Altered gut microbiota composition
Experts have raised the possibility that the reduction in cancer risk may not be solely attributed to the Mediterranean diet but also to lower consumption of ultra-processed foods.
While the study did not directly assess processed food intake, prior EPIC research has indicated a link between processed food consumption and an increased cancer risk.
Considering that the Mediterranean diet emphasises fresh, whole foods and excludes processed products, researchers suggest future studies should examine whether some obesity-related cancers could also fall under the category of processed-food-related cancers.
Conclusion
The EPIC study strengthens the evidence that adhering to the Mediterranean diet may reduce the risk of obesity-related cancers, though the observed risk reduction is modest. These findings add valuable insights to the growing body of research on the impact of dietary choices on long-term health outcomes.
Future studies are necessary to better understand the biological mechanisms behind these associations and the role processed foods play in cancer risk. This research highlights the importance of dietary habits in cancer prevention, as the conversation around nutrition continues to influence global health initiatives.