Medicinal mushrooms: what science says about lion's mane and health claims

Short summary

Medicinal mushrooms have surged in popularity, but this Science Weekly episode argues that robust scientific evidence backing many health claims is limited. The hosts, Ian Sample and Madeleine Finlay, explore popular products such as lion's mane and other fungal extracts, examining what lab research shows and what human trials actually demonstrate. They discuss how fungi may influence the immune system and the gut microbiome, the role of beta-glucans, and the gap between traditional medicine and Western science. With input from mycologist Nick Money, the episode cautions against overclaim while noting that mushrooms are unlikely to cause harm and emphasizing the need for rigorous, larger human studies before endorsing health benefits.

Overview

The episode examines the mushroom health trend, focusing on functional fungi like lion's mane and beta-glucan-rich products. It outlines the core claim that these mushrooms can boost cognition, cardiovascular health, and immune function, while acknowledging the paucity of high-quality human evidence. The conversation features Guardian science editor Ian Sample and mycologist Nick Money, who provides a scientific framework for evaluating mushroom-based health claims. The presenters discuss how fungi differ from plants, the microbiome context, and the difference between lab findings and real-world effects.

Evidence and What It Means

The core takeaway is that Western scientific evidence for health benefits from consuming medicinal mushrooms is limited. A major review highlighted that thousands of articles on mushroom effects yield few studies that warrant further exploration, and many experiments lack robust design. The segment emphasizes that cell and animal studies do not reliably predict human outcomes, and human trials tend to be small and underpowered. This section also notes that there have been a few human studies with mixed results, making it hard to draw firm conclusions about efficacy.

Lion's Mane and Cognitive Review

Lion's mane mushrooms are highlighted for potential cognitive benefits, with some studies showing modest improvements in people with mild cognitive impairment, though sample sizes are small. One randomized, placebo-controlled trial reported cognitive benefits after nearly a year of supplementation, but the small cohort (around 41 participants) means the result is suggestive rather than definitive.

"a randomized placebo controlled trial found cognitive benefits, but the sample size was only 41 people" - Ian Sample

Beta Glucans, Cancer and Diabetes

The discussion covers beta glucans, compounds in fungal cell walls that may act as adjuvants to cancer therapies and have shown some activity in lab studies. The consensus is that while the mechanism is plausible, human data are not robust enough to support routine use as cancer therapy. The dialogue also touches on diabetes research, where lab evidence suggests possible effects on blood sugar regulation, yet clinical relevance remains unproven in humans.

"beta-glucans can be useful as adjuvants in cancer therapy, but the evidence remains limited" - Madeleine Finlay

Mushrooms in Diet and Immunity

Experts discuss the nutritional value of edible mushrooms and compare this with their purported health benefits. They stress that mushrooms are low in calories and have limited vitamin and mineral density relative to many other foods, suggesting that benefits may come more from replacing unhealthy items than from mushroom consumption itself. The microbiome angle is explored, noting that fungi are a smaller but potentially influential component of gut ecosystems, with changes in gut fungi linked to diseases, though causation is not established.

"this is not going to harm you, but the evidence for real benefit is lacking" - Nick Money

Practical Takeaways and Next Steps

The episode concludes with pragmatic guidance for consumers: approaching mushroom products with reasonable expectations, avoiding overhyped claims, and recognizing the need for larger, high-quality human trials. It also highlights ongoing research areas, such as genome mining for novel fungal compounds and the broader role of fungi in medicine beyond nutrition. The key message is cautious interest rather than definitive endorsement, until better evidence emerges.