In a pooled analysis of 13 studies, researchers examined the relationship between the Mediterranean diet (MedDiet) and bladder cancer risk. They found high and medium adherence to the eating plan appeared to have a protective effect.
Based on studies that explore how food affects cancer likelihood, health organizations, including the American Cancer Society, advocate following a nutritious eating plan. This involves centering the diet on fruits, vegetables and whole grains while limiting red meat and processed meat.
The MedDiet is rich in anti-inflammatory foods, particularly fish, olive oil, fruit and vegetables. Since cancer growth is accelerated in a pro-inflammatory state, an anti-inflammatory diet would help lower the risk.
However, the specific role of diet in bladder cancer has not been determined, so scientists from various countries around the globe decided to examine the MedDiet’s impact on the disease.
Earlier research shows the diet lowers the risk of heart disease, Alzheimer’s disease and cancer in general, as well as reduces levels of LDL, or bad, cholesterol.
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The MedDiet is comprised mainly of plant-based foods of fruits, vegetables, whole grains, legumes and nuts. Instead of salt, it relies more on spices and herbs for flavoring; and rather than butter, it involves using the healthy fat of olive oil. The eating plan includes eating fish and poultry at least twice a week, and it limits red meat consumption to a few times per month.
Yet the MedDiet is more than a list of dietary inclusions and exclusions. According to the Mayo Clinic, it is actually a lifestyle that embraces getting regular exercise, enjoying meals with family and friends, and drinking red wine in moderation.
In the pooled analysis called the Bladder Cancer Epidemiology and Nutritional Determinants (BLEND) study, researchers looked at dietary data from more than 600,000 participants. Of these individuals, 2,425 received a bladder cancer diagnosis: 1,480 had the non-muscle-invasive type, and 945 had the muscle-invasive variety.
The participants were from Denmark, Australia, Spain, France, Greece, Germany, Italy, the Netherlands, Sweden, Norway, the United Kingdom and the United States.
Aside from dietary information, the data included gender, age, ethnicity, smoking status and bladder cancer pathology, which denoted whether the malignancy was muscle invasive or non-muscle invasive.
“At present, the better-established risk factors associated with developing bladder cancer include smoking, age, male sex, occupation and to a lesser extent obesity and physical inactivity,” the research team wrote. “Since most of the metabolites of ingested food come into direct contact with the bladder mucosa, diet might also play a role in the development of bladder cancer.”
After analyzing food intake data, the scientists categorized participants into three groups: low‑, medium- and high-adherence to the MedDiet.
They found men and former smokers had a higher risk of bladder cancer. In addition, they discovered those who in the diet’s medium- and high-adherence groups had a lower incidence of the cancer compared to those in the low-adherence group.
“We could not isolate any particular subgroup of foods (i.e. fats, alcohol) from the Mediterranean diet score that provided a greater benefit over others,” the researchers wrote. “This may be because it describes the overall effect of the combined factors of the dietary pattern to be most protective.”
The study was published in the European Journal of Nutrition.
Michelle Routhenstein, a preventive cardiology dietitian and owner of Entirely Nourished, told Olive Oil Times how the MedDiet may play a role in cancer prevention.
“The MedDiet is rich in anti-inflammatory foods, particularly fish, olive oil, fruit and vegetables,” she said. “Since cancer growth is accelerated in a pro-inflammatory state, an anti-inflammatory diet would help lower the risk. Moreover, the diet is rich in antioxidants, which quench free radicals that can turn into cancer growth, thereby helping to prevent cell mutation and cancer development.”