A long-term study of more than 36,000 Japanese men published in the International Journal of Cancer revealed that men who consume mushrooms are less likely to develop prostate cancer, reports Tohoku University.

Using two cohorts of Japanese men between ages 40 and 79, researchers monitored participants in 1990 and 1994 with follow-ups in 2014 and 2008, respectively. Men completed a questionnaire about their lifestyle choices: mushroom and other food consumption, physical activity, and smoking and drinking habits. In addition, participants provided information on their education and family and medical history.

Follow-up data showed that regular consumption of mushrooms was associated with a lower risk of prostate cancer in men—more specifically, those age 50 and older and whose diet mostly included meat and dairy products, with limited consumption of fruits and veggies. But after statistical analysis, a decreased risk was seen regardless of how much these foods were consumed.

Compared with men who consumed mushrooms less than once a week, those who consumed mushrooms up to twice a week had an 8% lower risk of prostate cancer and those who ate it more than three or more times per week saw a 17% reduced risk. (Only 3.3.% of participants developed prostate cancer during the follow-up period.)

Mushrooms contain L-ergothioneine, an antioxidant that decreases oxidative stress, which can be caused by poor diet as well as exposure to environmental toxins and can lead to chronic inflammation that contributes to diseases such as cancer. While L-ergothioneine is found in white button mushrooms, it is present in much higher concentrations in maitake, oyster and shiitake mushrooms. The study, however, did not identify which kinds of mushrooms men in Japan ate.

Japanese men also tend to consume more mushrooms in their diets than American men do. According to Shu Zhang, PhD, an assistant professor of epidemiology at Tohoku University in Japan and the lead study author, “Considering the average American consumes less than 5 grams of mushrooms per day, which is lower than that consumed by the participants in this study (7.6 g per day), one would expect that even a small increase in mushroom consumption to offer potential health benefits.”

Scientists will need to confirm such potential benefits by studying dietary intake of mushrooms in other populations and settings.

For related coverage, read “Flavonoids May Help Reduce the Risk of Cancer” and “Can Replacing Meat With Impossible Burgers Help Reduce Cancer Risk?”