A new study found higher intakes of nuts and seeds was associated with a reduce risk of prostate cancer and reduced risk of death from the disease, which is the most commonly diagnosed cancer in Australian men.

The global population-based study, which examined the impact of diet on prostate cancer, also found higher intakes of alcohol and processed meat increased prostate cancer risks (1).

Researchers examined data from 170 countries, including Australia, to determine links between diet and prostate cancer. This included data collection from the Global Cancer Observatory, Global Dietary Database, World Health Organisation, and the United Nations.

It showed each 1g increase in nut and seed intake was associated with a 2.0% lower incidence, 3.2% lower prevalence, and 0.8% lower mortality in prostate cancer. (Note: a handful of nuts is 30g.)

The protective association with nuts and seeds was not seen for any other food groups, including fruits, vegetables or whole grains.

The paper was published online in Nutrition and Cancer, ahead of print. The researchers stated that the data suggests consumption of nuts and seeds had a protective effect against prostate cancer formation, progression, and spread, while alcohol and processed meat increased these risks.

They concluded increased consumption of nuts and seeds, and lower intake of alcohol, seafood and processed meats might act as preventive measures against prostate cancer.

New AIHW data shows prostate cancer is the most commonly diagnosed cancer among Australian men. In 2020, 16,741 Australian men are expected to be diagnosed with prostate cancer and it’s estimated 3,152 Australian men will die from the disease.

More about the research

The study assessed 23 lifestyle and dietary factors and discovered a higher intake of nuts and seeds reduced the incidence, prevalence and mortality rates of prostate cancer.

The protective benefits of nuts remained highly significant even after adjusting for a range of factors including physical activity levels, obesity, socio-economic status, education and income.

The study findings are consistent with other research on nuts and prostate cancer, as well as nuts and cancer generally.

Among the studies highlighted in this paper was a Harvard prospective control study that found patients consuming nuts, five or more times per week, after being diagnosed with prostate cancer had significantly lower mortality rates than those consuming nuts less than once monthly (relative risk reduction of 34%).

Previous studies have found a 30g handful of nuts was associated with 15% reduced risk of total cancer and there is research that nuts provide protection against breast cancer.

In the discussion notes of this study, the researchers commented “nuts may affect carcinogenesis by inhibiting proinflammatory cell signalling pathways and thanks to its high dose of antioxidant. The main components suggested to be preventive agents against cancer are phyoestrogens, ellagic and oleic acids”.

The latest data shows only 2% of Australian eat the recommended 30g handful of nuts a day – an amount associated with the many health benefits of tree nuts.