From coffee alternatives to tinctures and gummies, medicinal mushrooms show promise in existing research – but that’s not the full story.
For millennia, mushrooms have been consumed and used in traditional medicine in cultures around the world. However, in the last few years, mushroom-based products have suddenly become ubiquitous. Products ranging from bottled tinctures to chocolate bars and powdered coffee alternatives promise everything from mental clarity and anti-aging to immune support and tumor suppression.
Indeed, industry analysis predicts pharmaceutical applications of mushrooms to be the fastest-growing segment of the market over the next few years. Worldwide, the functional mushroom market – which includes food, drinks, dietary supplements, and pharmaceuticals – was valued at nearly $26.7 billion in 2021 and is expected to grow to $65.8 billion by 2030, according to the report.
“The last few years are just unlike anything I’ve ever seen. The amount of interest that’s in fungi is just unparalleled,” says David Hibbett, a professor of biology at Clark University who specializes in the evolutionary biology of fungi.
As the “shroom boom” takes hold, questions remain as to the actual health benefits of these so-called superfoods. While some herbalists and other practitioners tout the therapeutic powers of various mushrooms, other mycologists are skeptical, even concerned, about these widespread claims.
Reishi, the “mushroom of immortality,” has been used medicinally in Asia for more than 2,000 years to promote health and longevity. More recently, the mushroom has found its way into commercial goods like gummies and dietary supplements that claim to do everything from promoting “restful sleep” to “overall wellness and vitality.”
New research has focused on reishi-derived beta-glucans, a soluble fiber shown to upregulate immune response and inhibit tumor growth in mice. A study conducted in 2023 found immune cell populations grew significantly more among the 126 human participants who were randomly administered reishi beta-glucans.
Shiitake mushrooms also contain a beta-glucan, called lentinan, that some herald for its anti-diabetic and immunotherapeutic potential in humans. The extract has been shown to suppress Type 1 diabetes in mice and improve immune response in cancer patients undergoing chemotherapy.
Chaga, whose medicinal use dates back to 12th century Europe, is another significant player in the functional mushroom market. The fungus has long been prescribed to cure digestive disorders, reduce inflammation, and even treat cancer. Recently, Inonotus obliquus polysaccharide (IOP), a bioactive chaga extract, has been shown to lower blood sugar levels in mice and inhibit the growth of human cancer cells in vitro.
… But existing research doesn’t tell the full story
Some experts warn existing research doesn’t provide sufficient evidence of health benefits and that more long-term clinical trials are needed.
Compared with human clinical trials, lab studies are highly controlled, and the findings don’t necessarily transfer to practical use, according to Heather Hallen-Adams, assistant professor of food science and technology at the University of Nebraska-Lincoln.
She adds that, while a growing body of research has shown that compounds in shiitake, turkey tail, and other mushrooms could have antitumor properties, the studies have largely been limited to labs using cancer cells in a Petri dish or genetically inbred rodents. Results seen in real people with different types of cancer and complex genetic backgrounds would likely be very different and remain “largely anecdotal” so far.
Lion’s mane, for instance, produces some biologically active compounds that seem to affect the growth of nerve cells. Early studies have also suggested the potential for positive impacts on cognitive function. “But that observation in itself doesn’t mean that if we go out and eat lion’s mane that we’re going to be able to ward off Alzheimer’s disease,” says Nicholas Money, a mycologist and biology professor at Miami University in Ohio.
Turkey tail, perhaps the most widely studied medicinal mushroom, according to John Michelotti, a mycologist and founder of Catskill Fungi, is also of great interest for its long-established role in treating cancer. In a landmark 1994 paper, Japanese researchers found that administering polysaccharide K (PSK) – a turkey tail ac
As the medical director of integrative medicine at Memorial Sloan Kettering Cancer Center, Gary Deng often looks to natural remedies – like mushrooms, herbs, and acupuncture – from other medical traditions for supplementary treatment. He sometimes recommends polysaccharide extract from turkey tail as a supplement for selected patients. However, he’s quick to warn people against self-prescribing without a doctor’s approval.
“Every person has a unique clinical situation,” he says.
As compelling as the existing research may be, there are some obvious limitations. “The vast majority of studies are not double-blind, placebo-controlled clinical studies” – the standard in drug-approval processes, Hibbett says. “It’s a really dicey literature…Until you get to clinical studies with actual people, you’re not in a position to say that a product has actual health benefits.”
And, as many studies as there are showing positive impacts in humans, he adds, there are some showing mixed results – or none at all.
In Japan and China, certain mushroom compounds, like lentinan and PSK, have received approval for use in conjunction with chemotherapy to treat cancer patients. However, they’re far from entering the American pharmaceutical industry. Though a handful of clinical studies are currently underway, no mushroom extracts have yet been approved by the U.S Food and Drug Administration.
The “wild west” of mushroom supplements
Ongoing debate over the medicinal properties of mushrooms has hardly slowed the industry. Edible mushrooms have become a staple of the supplement aisle, with powdered mushroom mixes, concentrated tinctures, and other goods that boast a smorgasbord of health benefits.
But the distribution of fungi-containing supplements remains almost completely unregulated – something that has made some experts nervous. The production, dosage, and effects of FDA-approved drugs are strictly regulated – which isn’t the case with supplements. And studies have shown that the mushrooms allegedly contained within certain products are mislabeled or not present at all.
As the scientific community delves deeper into the therapeutic potential of mushrooms, it’s crucial for consumers to approach these supplements as complementary to, rather than a replacement for, established medical treatments. The positive effects experienced by many users might be attributed, in part, to a placebo effect or heightened belief in their efficacy. While the journey into the world of mushroom supplements is fascinating, a balanced and informed perspective is key in navigating this burgeoning field.