Mediterranean Diet: New research suggests that following a Mediterranean diet may reduce the risk of obesity-linked cancers, including liver and kidney cancer.
The study shows that even moderate adherence offers some protection, highlighting the role of diet in cancer prevention.
Mediterranean Diet, A recent JAMA Network Open study determines whether adherence to the Mediterranean diet (MedDiet) influences the risk of developing obesity-related cancers.
How Does Obesity Affect Cancer Risk?
Mediterranean Diet, The prevalence of both obesity and being overweight significantly increased between 1975 and 2016 in both male and female adults, with one recent study estimating that 39% of the global population is now considered obese or overweight. The International Agency for Research on Cancer has reported that excess body weight is associated with a greater risk of developing cancer at thirteen anatomical sites, including the kidney, liver, breast, endometrium, and esophagus.
Multiple epidemiologic studies and clinical trials have reported the beneficial effects of MedDiet on promoting weight loss and reducing abdominal adiposity. For example, the European Prospective Investigation into Cancer and Nutrition (EPIC)-Spain cohort study identified an inverse relationship between high adherence to the MedDiet and obesity risk among individuals with excessive body weight. Likewise, another study demonstrated that the MedDiet improved survival rates after a breast cancer diagnosis.
The EPIC study also revealed a 4% reduction in overall cancer risk for every two-point increase in the MedDiet score, with greater point values reflecting higher adherence to this diet. Similar observations were published in a recent meta-analysis reporting that higher MedDiet adherence reduces cancer mortality risk and specific cancer incidence.
Several factors, including genetic susceptibility, hypoxia, insulin resistance, adipokines, stromal cells, inflammation, and growth factors, are involved in the relationship between obesity and cancer. To date, it remains unclear whether adiposity mediates MedDiet’s beneficial role in obesity-related cancers (ORCs).
About The Study
The current study examined the association between adherence to the MedDiet and the risk of ORC in the EPIC cohort, which comprises 521,324 individuals between 35 and 70 from 23 centers across 10 countries. The researchers also determined whether this association was mediated by body mass index (BMI) and waist-to-hip ratio (WHR) measurements.
Individuals diagnosed with cancer at baseline, lacking diagnosis or follow-up information, and without dietary or lifestyle data were excluded from the analysis.
The analysis considered fourteen food groups and nutrients. It estimated each participant’s daily intake in grams of different dietary components and total energy intake.
The Mediterranean Diet pattern was measured using the Mediterranean Diet score (MDS) and relative Mediterranean Diet score (rMedDiet). The incident cancer cases in the EPIC study were identified during the 14.9-year follow-up period.
Study Findings
A total of 450,111 study participants, 29.2% of whom were men and 70.8% women from the EPIC cohort, met the eligibility criteria for the current study. The mean age of the study participants was 51.1 years. At baseline, the mean BMI was 25.3, whereas the mean WHR was 0.8.
Approximately 4.9% of study participants who were not diagnosed with cancer at baseline developed ORC during the study follow-up period. This includes 0.053, 0.049, and 0.043 per person-years in the low, medium, and high Mediterranean Diet adherence groups.
Individuals with the highest MDS scores reported higher education levels, were more likely to be younger, non-smokers, less physically active, and have high energy intake. In the fully adjusted model, greater Mediterranean Diet adherence was associated with a lower risk of ORC.
A similar association was observed between medium Mediterranean Diet adherence and ORC; however, no association was identified when the MDS was modeled continuously. These findings were consistent with sensitivity analyses, which used the rMedDiet score and multivariable-adjusted model.
A site-specific ORC assessment indicated an inverse association between higher adherence to the Mediterranean Diet and risk of hepatocellular, colorectal, and kidney cancers. Medium adherence to the Mediterranean Diet was also inversely associated with esophageal cancer; however, this association was not observed for postmenopausal breast, endometrial, and ovarian cancer.
Stratified analyses revealed an inverse association between adherence to the MDS and risk of ORC in former smokers. Taken together, a lower risk of incident ORC was associated with moderate alcohol intake and lower meat consumption. The mediation analysis did not identify a significant association between high and low MedDiet adherence and the risk of ORC mediated by BMI or WHR.
Final Thought
Mediterranean Diet, The study findings confirm that higher adherence to the Mediterranean Diet may moderately reduce the risk of ORCs, with medium adherence associated with a smaller reduction in the risk of certain cancers. In the future, additional research is needed to elucidate the mechanisms by which higher Mediterranean Diet adherence may reduce the risk of developing cancer.
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