The men were also asked to provide information on their education, and family and medical history.

After following one group of men for 24.5 years and another for 13.25 years, the researchers found that the men who consumed mushrooms once or twice a week had an 8 percent lower risk of developing prostate cancer -- regardless of how much fruit and vegetables, or meat and dairy products they ate -- compared to those who ate mushrooms less than once per week.

Eating mushrooms more often appeared to bring even bigger benefits, with those who consumed mushrooms three or more times per week showing a 17 percent lower risk than those who ate mushrooms less than once a week.

Eating mushrooms also appeared to be particularly beneficial among men aged 50 and older and amongst those who ate a large amount of meat and dairy products and little fruit and vegetables.

The findings, published in the International Journal of Cancer, are the first to suggest that there may be an association between eating mushrooms and a lower risk of prostate cancer, which is one of the most common forms of cancer affecting men.

"Test-tube studies and studies conducted on living organisms have shown that mushrooms have the potential to prevent prostate cancer," said lead researcher Shu Zhang. "However, the relationship between mushroom consumption and incident prostate cancer in humans has never been investigated before."

"To the best of our knowledge, this is the first cohort study indicating the prostate cancer-preventive potential of mushrooms at a population level."

Zhang added that, "mushrooms are a good source of vitamins, minerals and antioxidants, especially L-ergothioneine," which is believed to help fight against oxidative stress, which is a cellular imbalance caused by lifestyle choices such as poor diet and exposure to environmental toxins. This imbalance can lead to chronic inflammation, resulting in chronic diseases such as cancer.

"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/day) one would expect that even a small increase in mushroom consumption to offer potential health benefits," said Zhang. However, Zhang added that, "Although our study suggests regular consumption of mushrooms may reduce the risk of prostate cancer, we also want to emphasize that eating a healthy and balanced diet is much more important than filling your shopping basket with mushrooms."