Largest study ever that expanded over 3 decades and involved 36,000 participants indicates that an antioxidant found in mushrooms, L-ergothioneine lowers the risks of prostate cancer.
Medical Researchers From Tohoku University in Sendai, Japan have discovered through a long term study that involved more than 36,000 Japanese men, that eating mushrooms effectively lowered the risk of prostate cancer.The findings involving two long term cohort studies were published in the International Journal Of Cancer last month.
Prostate cancer affects about 16.8 million men globally with 60 percent being males over the age of 65. In 2018 alone, 1.02 million new cases were diagnosed. One in 18 males affected by the disease will die within the first year of diagnosis. Prostate cancer begins when cells in the prostrate gland, a small walnut-shaped gland found only in men, which produces the fluid that forms part of the semen,start to grow out of control. It is one of the most common forms of cancer affecting men.
Consumption of mushrooms is extensive in Asia and they are well known for both; their nutritional value and medicinal properties. Mushrooms are a good source of vitamins, minerals and antioxidants, especially L-ergothioneine which is believed to mitigate against oxidative stress, a cellular imbalance resulting from poor diet and lifestyle choices and exposure to environmental toxins that can lead to chronic inflammation that is responsible for chronic diseases such as cancer.
Asst Professor Dr Shu Zhang, an epidemiologists in the De partment of Health Informatics and Public Health at Tohoku University School of Public Health, Graduate School of Medicine in Japan, and lead author of the study commented in a phone interview with Thailand Medical News "Test-tube studies and studies conducted on living organisms have shown that mushroom have the potential to prevent prostate cancer. However, the relationship between mushroom consumption and incident of prostate cancer in humans has never been investigated before till now"
He further added, "To the best of our knowledge, this is the first cohort study indicating the prostate cancer-preventive potential of mushrooms at a population level. 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 cart with mushrooms."
The medical researchers monitored two cohorts consisting of a total of 36,499 men between the ages of 40 and 79 years in Miyagi and Ohsaki, Japan, from 1990 and 1994 respectively. The follow-up duration for the Miyagi cohort extended from June 1, 1990 to December 31, 2014 (24.5 years), while the follow-up duration for the Ohsaki cohort extended from January 1, 1995 to March 31, 2008 (13.25 years).
The participants were asked to complete a questionnaire related to their lifestyle choices, such as mushroom and other food consumption, physical activity, smoking and drinking habits, as well as provide information on their education, and family and medical history.
Follow-up of the participants on a long term basis indicated that consuming mushrooms on a regular regimen reduces the risk of prostate cancer in men, and was especially significant in men aged 50 and older and in men whose diet consisted largely of meat and dairy products, with limited consumption of fruit and vegetables.
Detailed statistical analysis of the data (using the Cox proportional hazards model) indicated that regular mushroom consumption was related to a lower risk of prostate cancer regardless of how much fruit and vegetables, or meat and dairy products were consumed. Of the total participants, about less than 2% developed prostate cancer during the follow-up period. Participants who consumed mushrooms once or twice a week had about 10 % lower risk of developing prostate cancer, compared to those who ate mushrooms less than once per week, while those who consumed mushrooms three or more times per week had about a 20% lower risk than those who ate mushrooms less than once a week.
The results of our study suggest mushrooms may have a positive health effect on humans," said Zhang. "Based on these findings, further studies that provide more information on dietary intake of mushrooms in other populations and settings are required to confirm this relationship.
The researchers are also planning to do more research on the antioxidant, L-ergothioneine found in the mushrooms and to see its role in prostate cancer specifically and to even try map out is cellular pathway and to conduct clinical trials in the future to assess whether it could be used as a therapeutic drug by itself.
Shu Zhang et al, Mushroom consumption and incident risk of prostate cancer in Japan: A pooled analysis of the Miyagi Cohort Study and the Ohsaki Cohort Study, International Journal of Cancer (2019). DOI: 10.1002/ijc.32591