A large cohort study from Japan found that eating mushrooms may be associated with a reduced risk for prostate cancer. The association was particularly notable among those aged 50 years and older.
“To date, an increasing number of in vivo and in vitro studies have suggested the beneficial effects of mushrooms on health, such as antioxidation, anti‐inflammation, immunomodulation, etc,” wrote study authors led by Shu Zhang, PhD, of Tohoku University School of Public Health in Sendai, Japan. “Additionally, mushrooms also reportedly have anticancer properties and effects against tumor development.”
Results from the study were published online ahead of print on September 4 in the International Journal of Cancer.
There have been suggestions that several mushroom extracts may inhibit human prostate cancer cell lines and restrict tumor progression. To better elucidate any potential connection between mushroom intake and prostate cancer, the authors conducted an analysis based on a total of 36,499 men who participated in the Miyagi Cohort Study in 1990 and the Ohsaki Cohort Study in 1994. The men were followed for a median of 13.2 years.
The participants were divided by mushroom consumption: 15,958 men consumed mushrooms less than once per week; 13,124 ate them 1 to 2 times per week; and 7,417 men ate mushrooms at least three times per week. Those who ate the most mushrooms were older, more likely to have a family history of cancer, and less likely to be current smokers or drinkers. They also were more likely to spend at least 1 hour per day walking.
The study covered a total of 574,397 person-years of follow-up, during which period there were 1,204 cases of prostate cancer (3.3% of the population). Using the lowest mushroom consumption group as a reference group, those who ate mushrooms at least three times per week had an unadjusted hazard ratio for prostate cancer development of 0.84 (95% CI, 0.72–0.98; P = 0.033).
This was confirmed in two adjusted models. In one, the researchers adjusted for family history, body mass index, education level, smoking status, and time spent walking; in that model, the HR for the highest mushroom consumption group was 0.84 (95% CI, 0.72–0.98; P = 0.025). In a second model that additionally adjusted for consumption of other foods including meat, vegetables, fruit, dairy products, coffee, and others, the HR was 0.83 (95% CI, 0.70–0.98; P = 0.023).
A stratified analysis based on age, clinical cancer stage, and other foods showed that the relationship persisted among those aged 50 years and older, while no significant relationship was seen in younger men.
This adds to previous studies suggesting mushroom intake may help reduce risk of cancer development. For example, a 2010 study found that higher mushroom consumption was related to a reduced risk for breast cancer.
“This finding suggests that habitual mushroom intake might help to reduce prostate cancer risk,” the authors of the new study concluded. “Further studies in other populations and settings are required to confirm this relationship.”