is the most common type of cancer in men with a high mortality rate. Studies have linked prostate cancer to environmental, occupational and dietary factors. Recent studies have investigated whether diet can lower the risk of cancer, but the results have been inconsistent.
A research team studied the relationship between dietary patterns and the risk of prostate cancer as part of the MCC-Spain study, a Spanish case-control study. The study involved 733 patients with prostate cancer and 1,229 healthy men with a mean age of 66 years from Spanish regions. The research team collected anthropometric, epidemiologic and dietary data.
‘High adherence to a Mediterranean diet which is not only rich in fruits and vegetables but also in fish, legumes and olive oil was associated with lower risk of prostate cancer.’
The team evaluated the adherence to three dietary patterns - Western, Prudent and Mediterranean, which characterize the dietary habits of the Spanish population.
The Western diet
includes consumption of large amounts of high-fat dairy products, refined grains, processed meat, high-calorie beverage, fast food, sweets and sauces.
The Prudent diet
includes consumption of low-fat dairy products, whole grains, fruits, vegetables and juices.
The Mediterranean diet
consists of high consumption of fish, fruits, vegetables, boiled potatoes, legumes, and olive oil, and low consumption of juices.
The participant's diet was graded according to the degree of adherence to each diet from lower to higher. The findings showed that high adherence to Mediterranean diet appeared to be associated with a lower risk of aggressive prostate cancer.
Prudent and Mediterranean diet showed different effects in low and high-grade tumors.
Prostate cancer risk was assessed using Gleason scores of tumor aggressiveness (<6 or >6) and clinical stage (cT1b to cT4). A Gleason score of <6 indicates a less aggressive tumor with good prognosis. Lower clinical stage (cT1-cT2a) indicates that prostate cancer that has not spread.
The findings indicated that for aggressive prostate cancer (Gleason >6 and stages cT2b to cT4), only high adherence to the Mediterranean diet showed a protective effect. Other dietary patterns such as Prudent and Western diet showed little or no correlation and did not achieve statistical significance.
Commenting on the findings, Adela Castelló, co-author of the study, said, "There is a striking contrast between the relevance of prostate cancer in terms of public health and the evidence regarding its primary prevention."
"If other studies confirm these results, the promotion of the Mediterranean dietary pattern might be an efficient way of reducing the risk of developing advanced prostate cancer, in addition to lowering the risk of other prevalent health problems in men such as cardiovascular disease. Dietary recommendations should take into account whole patterns instead of focusing on individual foods," said Castelló, Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Instituto de Salud Carlos III (Madrid).
The findings of the study are published in The Journal of Urology
"This study adds important evidence to the scarce information regarding the association of diet with prostate cancer, and highlights the relevance of focusing on global dietary patterns," explained lead investigator Beatriz Perez-Gomez, PhD, Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Instituto de Salud Carlos III (Madrid).
"Our results show that a diet oriented towards the prevention of aggressive tumors in the prostate should probably include important elements of the Mediterranean diet such as fish, legumes, and olive oil, and suggest that a high intake of fruits, vegetables, and whole grains might not be enough."
- Adela Castelló, Elena Boldo, Pilar Amiano, et all. "Mediterranean Dietary Pattern is Associated with Low Risk of Aggressive Prostate Cancer: MCC-Spain Study." The Journal of Urology, (2018); 199 (2): 430 DOI: 10.1016/j.juro.2017.08.087