New research finds that closely following a whole Mediterranean dietary pattern — that is, incorporating a high intake of not only vegetables, fruits, and whole grains, but also of legumes, fish, and olive oil — is tied to a lower risk of aggressive prostate cancer.
In a report on their findings that is published in The Journal of Urology, the researchers write that guidelines for preventing prostate cancer should aim to "consider whole dietary patterns instead of individual foods."
Lead investigator Dr. Beatriz Pérez-Gómez, from the Instituto de Salud Carlos III at the University of Alcalá near Madrid, Spain, explains that key elements "such as fish, legumes, and olive oil" should likely be included when suggesting a diet to prevent aggressive prostate cancer.
This is because their results "suggest that a high intake of fruits, vegetables, and whole grains might not be enough."
Prostate cancer occurs because of the uncontrolled growth of cells in the prostate, which is a gland in the male reproductive organs that produces a fluid that forms part of semen. It sits just below the bladder and surrounds the urethra, the tube that urine passes through on its way out of the body.
Prostate cancer accounts for 1 in 10 cases
The prostate gland is normally the size of a walnut. However, it is not uncommon, as men age, for their prostate to grow bigger, put pressure on the urethra, and cause problems with urine flow.
This condition — known as benign prostatic hyperplasia, or enlarged prostate — is not cancerous. There are also other non-cancerous conditions that can cause changes in the prostate.
In 2017, there were an estimated 161,360 new cases of prostate cancer in the U.S., accounting for nearly 10 percent of all cases of cancer.
Rates of death to the disease have been falling in recent years, and more than 98 percent of men with prostate cancer now survive for more than 5 years after diagnosis.
But a common theme is that they emphasize certain key components that include: high intakes of vegetables, fruits, whole cereals, legumes, and olive oil; moderate intakes of fish, meat, dairy, and red wine; and low intakes of eggs and sweets.
'Western, prudent, and Mediterranean' diets
The research examined data from a case-control study of 733 men with prostate cancer and 1,229 healthy men. The average age of the men, who came from seven different parts of Spain, was 66 years.
The study collected a range of data that included not only medical and background information, but also details about their eating habits.
The researchers put the participants into three groups according to which dietary pattern most closely matched their eating habits. The dietary patterns, which are the most common in Spain, were "Western, prudent, and Mediterranean."
In the Western diet, the pattern includes large intakes of fatty dairy foods, processed meats, fast food, refined grains, sweets, sauces, and high-calorie drinks.
The prudent dietary pattern comprises low-fat dairy foods, fruits, vegetables, whole grains, and juices.
Typical features of the Mediterranean pattern defined in this study were high intakes of fish, fruits, vegetables, boiled potatoes, legumes, and olive oil, with low levels of juice intakes.
The researchers categorized each participant within his dietary group according to how closely his eating habits fit with the dietary pattern. Therefore, each dietary pattern had four categories of adherence, ranging from low to high.
In the case of the men diagnosed with prostate cancer, the team categorized the aggressiveness of the disease according to their Gleason score and clinical stage.
Follow Mediterranean diet for reduced risk
Next, they compared the patterns of adherence in the men with prostate cancer and the men who were healthy.
The scientists found that only a "high adherence to the Mediterranean dietary pattern" was significantly associated with a reduced risk of having prostate cancer with aggressive and extensive tumors.
No such link was found in the other dietary patterns, either with aggressive or less aggressive tumors.
The researchers suggest that, subject to other studies confirming their findings, recommending that men closely follow the Mediterranean dietary pattern might be an effective way to reduce the risk of advanced prostate cancer.
"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."
Dr. Beatriz Pérez-Gómez