Mushrooms (the food kind, not the psychedelic kind) may help stave off prostate cancer, according to a new study published in the International Journal of Cancer. The study, conducted by a group of researchers at Tohoku University in Japan in collaboration with researchers from the U.S., found that men who ate mushrooms more than three times a week had a 17 percent lower risk of developing prostate cancer than men who ate mushrooms fewer than on time per week.
The nearly 36,500 men involved in the study were all men between the ages of 40 and 79. The researchers tracked the men for 13 years, during which time about 3.3 percent of the men developed prostate cancer. After analyzing the cancer incidence alongside the mushroom intake, the researchers said that their findings, "suggested a beneficial effect of habitual mushroom consumption on prevention of prostate cancer."
Read MoreBased on the study's findings, it's tempting to say flat-out that men who eat a lot of mushrooms are less likely to get prostate cancer. This could be partially true, but it's unlikely that the mushroom consumption was the only thing contributing to the lower risk. Think about it mushrooms aren't typically part of the ingredient list for junk foods, right? They're part of a healthy diet, and people who eat healthy diets tend to be more healthy overall. They may be less likely to be overweight, for instance, and they may be more likely to engage in physical activity. All of these factors contribute to a lower prostate cancer risk.
Indeed, the lead author of this study, Dr. Shu Zhang of Tohoku University School of Public Health, noted that the men who ate the most mushrooms in his study also "spent more time walking and had a higher intake of meat, vegetables, fruit, dairy products, and energy. They were also less likely to be current smokers."
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In other words, mushrooms aren't necessarily a quick fix for prostate cancer risk. Instead, they are likely one element of an overall healthier approach to eating and exercise that will help you avoid cancer in your older age.
Dr. Stephen Freedland, Director of the Center for Integrated Research in Cancer and Lifestyle at the Cedars-Sinai Medical Center, echoed this point when he told SurvivorNet in a previous conversation that maintaining a healthy weight plays a big role in lowering prostate cancer risk and mortality.
“Some of the best data we have is that obesity increases the risk of not just getting prostate cancer, but actually dying from prostate cancer,” Dr. Freedland said. “Obese men are about 35% more likely to die from prostate cancer.”
Diets that lead to obesity usually contain a lot of simple sugars and trans fats, Dr. Freedland explained. “So that’s the things that we focus on, trying to get out those simple sugars – the cookies, the cakes, the candies, getting out the trans fats.”
Dr. Stephen Freedland spoke with SurvivorNet about the link between prostate cancer and obesity
Prostate Cancer Risk Increases After Age 65 — Mushrooms or No Mushrooms
Interestingly, the researchers pointed out that, among the men in their study who were under 50 years old, there was no significant difference in prostate cancer risk according to mushroom intake. "This could be due to the fact that the incidence rate of prostate cancer in this subgroup (under 50) was too low to provide sufficient statistical power," the researchers explained. In other words, because prostate cancer is less common in younger men to begin with, the researchers didn't have enough cases to note a difference.
“If we live long enough, most men, the majority of men, will have prostate cancer,” Dr. Geoffrey Sonn, a urologist with Stanford Medicine, told SurvivorNet. The average age of a prostate cancer diagnosis is 66, according to the American Cancer Society. Given that the majority of prostate cancer diagnoses (about six in 10) occur after age 66, it makes sense that the researchers did not have enough data to analyze the risk in men younger than 50.
Prostate cancer is highly common, but luckily, if it’s diagnosed early enough — meaning before it has spread beyond the prostate gland — it has almost an 100 percent five-year survival rate. That’s why, as men age, it’s incredibly important to be vigilant about screening.
Dr. Edwin Posadas spoke with SurvivorNet about when men should get tested for prostate cancer.
Prostate cancer screening is simple. Usually, it consists of a prostate-specific antigen (PSA) blood test and a digital rectal exam to feel the prostate gland. "It's slightly uncomfortable but painless, and takes less than 30 seconds," Dr. Edwin Posadas, Medical Director of the Urologic Oncology Program at Cedars-Sinai Medical Center, told SurvivorNet in a previous conversation about prostate cancer screening.
"The amount of information that is gained from that is tremendous, and it can be a life-and-death type decision that is made," Dr. Posadas added.
RELATED: When Should I Get Tested for Prostate Cancer?
OK, But Back to the Mushrooms – How, Exactly, Do They Lower Prostate Cancer Risk?
With association studies like this one, it's really important to remember that the findings don't necessarily mean that the mushrooms caused the lower prostate cancer risk. Mushrooms have a ton of healthy nutrients such as vitamin B and fiber, but the researchers didn't look into whichif anycharacteristics of mushrooms played a role in prostate cancer risk. Actually, they didn't even differentiate the species of mushroom that the men in the study were eating, which is significant because there are a lot of mushroom species, many of which have different nutritional values.
Having said that, the researchers did point to several possible ways that mushrooms could play a role in lowering prostate cancer risk (though they noted that more research would be needed to say for sure.)
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One possibility may be mushrooms' antioxidant-rich properties, which Dr. Zhang writes, "might mitigate oxidative stress," (a process that can damage cell DNA and cause it to develop cancerous mutations). These antioxidants, he said, are most likely to be found in shiitake, oyster mushrooms, maitake and white button mushrooms.
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