Cancer Survival and Medicinal Mushrooms

Did the five randomized controlled trials of reishi mushrooms in cancer patients show benefits in terms of tumor response rate, survival time, or quality of life?

Can mushrooms be medicinal? Mushroom-based products make up a sizable chunk of the $50 billion supplement market. “This profitable trade provides a powerful incentive for companies to test the credulity of their customers and unsupported assertions have come to define the medical mushroom business.” For example, companies marketing herbal medicines “exploit references to studies on mice in their promotion of mushroom capsules and throat sprays for treating all kinds of ailments”—but we aren’t mice.

It wouldn’t be surprising if mushrooms had some potent properties. After all, fungi are where we’ve gotten a number of drugs, not the least of which is penicillin, as well as the cholesterol-lowering drug lovastatin and the powerful immunosuppressant drug cyclosporin. Still don’t think a little mushroom can have pharmacological effects? Don’t forget they can produce some of our most powerful poisons, too, like the toxic Carolina false morel that looks rather toadstooly, while others, as you can see here and at 1:15 in my video Medicinal Mushrooms for Cancer Survival, have a more angelic look like the destroying angel—that is its actual name—and as little as a single teaspoon can cause a lingering, painful death.

We should have respect for the pharmacological potential of mushrooms, but what can they do that’s good for us? Well, consuming shiitake mushrooms each day improves human immunity. Giving people just one or two dried shiitake mushrooms a day (about the weight-equivalent of five to ten fresh ones) for four weeks resulted in an increase in proliferation of gamma-delta T lymphocytes and doubled the proliferation of natural killer cells. Gamma-delta T cells act as a first line of immunological defense, and, even better, natural killer cells kill cancer. Shiitake mushrooms did all this while lowering markers of systemic inflammation.

Oyster mushroom extracts don’t seem to work as well, but what we care about is whether mushrooms can actually affect cancer outcomes. Shiitakes have yet to show a cancer survival benefit, but what about reishi mushrooms, which have been used as a cancer treatment throughout Asia for centuries?

What does the science say about reishi mushrooms for cancer treatment? A meta-analysis of five randomized controlled trials showed that patients who had been given reishi mushroom supplements along with chemotherapy and radiation were more likely to respond favorably,  compared to chemotherapy/radiotherapy on its own. Although adding a reishi mushroom extract improved tumor response rates, “the data failed to demonstrate a significant effect on tumour shrinkage when it was used alone,” without chemo and radiation. So, they aren’t recommended as a single treatment, but rather an adjunct treatment for patients with advanced cancer.

“Response rate” just means the tumor shrinks. Do reishi mushrooms actually improve survival or quality of life? We don’t have convincing data suggesting reishi mushroom products improve survival, but those randomized to reishi were found to have “a relatively better quality of life after treatment than those in the control group.” That’s a win as far as I’m concerned.

What about other mushrooms? Although whole shiitake mushrooms haven’t been put to the test for cancer yet, researchers have said that lentinan, a compound extracted from shiitakes, “completely inhibits” the growth of a certain kind of sarcoma in mice. But, in actuality, it only worked in one strain of mice and failed in nine others. So, are we more like the 90% of mouse strains in which it didn’t work? We need human trials—and we finally got them. There are data on nearly 10,000 cancer patients who have been treated with the shiitake mushroom extract injected right into their veins. What did the researchers find? We’ll find out next.

Doctor’s Note

Stay tuned for White Button Mushrooms for Prostate Cancer.

Also check out Friday Favorites: Mushrooms for Prostate Cancer and Cancer Survival.

For more on mushrooms, see Breast Cancer vs. Mushrooms and Is It Safe to Eat Raw Mushrooms?.