In a new study, researchers found that men who eat 10 or more portions of tomato-rich foods a week are 18 percent less likely to develop prostate cancer.
This was a case controlled study, and not a randomized controlled trial, meaning researchers looked at the diet, lifestyle and weight of men who had had a prostate check and were subsequently diagnosed with (cases) and without (controls) prostate cancer. The researchers wanted to see if there were any factors that reduced the risk of being diagnosed with prostate cancer.
The researchers used data collected from a large UK study called the ProtecT trial. In this trial, 227,300 randomly selected men aged 50 to 69 were invited to have a prostate check between 2001 and 2009.
Nearly half of the men then had a prostate specific antigen (PSA) test and 11% of them went on to have further investigations. Before the test they were asked to fill out questionnaires on:
- alcohol intake
- medical history
- family history
They were also asked to provide information on their:
- physical activity level
- body mass index (BMI)
- waist circumference
- body size aged 20, 40 and at the time they entered the study
From this study, the researchers identified 2,939 men who had been diagnosed with prostate cancer and matched them with 20,781 randomly selected men by age and GP practice who did not have prostate cancer to act as controls.
The researchers also looked at the intake of components of the “prostate cancer dietary index”: calcium, selenium and tomato products which they used as an indicator of lycopene intake (tomato juice, tomato sauce, pizza and baked beans).
The study cannot prove that eating more tomatoes prevents prostate cancer, it can only show an association.
The association is thought to be from lycopene, in which tomatoes are a rich source of, a nutrient thought to protect against cell damage. However, it’s still in question if it really does protect cells.
The research also found the health benefits were even found in processed tomato products such as baked beans, ketchup, pizza and tomato juice.
Paul Bennett, deputy CEO of Prostate Cancer Research said: “The great thing about this is that it is something everyone can do. Eating more tomatoes isn’t going to have a bad impact. It’s something so simple. It’s not a drastic change and it’s not asking men to completely change their lifestyle. People should definitely embrace the idea.”
The researchers concluded that, “in addition to meeting the optimal intake for the three dietary factors associated with prostate cancer, men should maintain a healthy weight and an active lifestyle to reduce risk of developing prostate cancer, cardiovascular diseases and diabetes”. They also say that “high intake of plant foods and tomato products in particular may help protect against prostate cancer, which warrants further investigations”.
Prostate cancer is the second most common cancer in men worldwide.
The study was published in the medical journal Cancer Epidemiology, Biomarkers and Prevention.