Prostate cancer is the most common form of cancer among men. The prostate-specific antigen (PSA) is regarded as the parameter for diagnosing prostate cancer. The higher this value, the higher the probability of disease. The ratio between free and bound PSA is an even stronger bio-marker. The lower this ratio, the more probable the occurrence of prostate cancer.

Various studies have managed to show that the anti-oxidant tocopherol (Vitamin E) impedes the growth of malign cancer cells, including prostate cancer cells.

Walnuts are rich in Vitamin E, with 75 g walnuts containing 16 mg tocopherol. Similarly, walnuts also contain ellagic acid - a polyphenol - which has the property of furthering apoptosis (cell death) and angiogenesis (the formation of new blood vessels), thus acting as an anti-carcinogen.

The aim of an experimental study was to investigate the effect of supplementing the diet of male patients who had an increased risk of prostate cancer with 75 g walnuts per day and then investigating the prostate bio-markers and the tocopherol in the serum.

The results of the study showed that the tocopherol content of the serum significantly increased within 4 to 8 hours. In the same way, it was observed that the free PSA increased after eight weeks of supplementing the diet with walnuts.  This allows the conclusion to be drawn that walnuts improve the prostate bio-marker values and consequently serve to protect against prostate cancer. Adequate consumption of walnuts can thus make a contribution to the prevention of prostate cancer and should be integrated into the daily diet.

Source: Sparccarotella KJ, Kris-Etherton PM et al. (2008): The effect of walnut intake on factors related to prostate and vascular health in older men. Nutrition Journal, 7:13.