Mushrooms, Medicine, and Wishful Thinking

Understanding the limitations of supplements doesn't make mushrooms less magical. It just makes you a better consumer.

The other day I participated in a zoom meeting with a colleague whose young employee recently read about functional mushrooms, a convenient marketing term for mushrooms that have purported health benefits. “I can’t believe I didn’t know about this!” She exclaimed. “Why doesn’t everybody know about these mushrooms?” I didn’t mean to be blunt, but I was. I just blurted out, “Because they don’t work,” which is not totally true, but neither is it true that functional mushrooms predictably change health outcomes. Still, the look of disappointment on her face made me feel like a jerk, as if I’d just told her Santa didn’t exist.

I suspect she had been sold on the idea that certain mushrooms hold special healing powers. Many folks believe this to be the case and will argue—and I’ve heard this countless times from mycophiles—that the reason why mushrooms aren’t widely prescribed is due to the influence of Big Pharma or the AMA or whatever capitalistic entity benefits from you NOT being able to access a healing medicine outside of their control. There are many fucked up things in our country right now, but in my opinion, this is not one.

What may be more pernicious is when industry takes advantage of vulnerable consumers who have developed unrealistic expectations about what mushrooms can do for them. When I first began my study of mushrooms, I totally believed they constituted a superfood, and that they had tremendous capacity to heal. I think I am not alone in having my mind blown when I first learned about a whole kingdom of life I’d never heard of before. Why wouldn’t I think fungi might be capable of, well, anything? But during the course of my study, I had to modify those expectations. It didn’t make the mycological world less magical and amazing to me (in fact, the deeper I’ve gone the more staggering it is). What it did give me was context that helped put in perspective some of the claims I was hearing from the food and supplement industries.

Medical Versus Medicinal Mushrooms

For me, the first step in becoming more supplement savvy was understanding the difference between medical and medicinal mushrooms. The late mycologist Tom Volk explained it to me. Medical fungi are fungi that cause disease like Candida auris, a very serious multi-drug resistant pathogen. Anyone who thinks fungi are by nature beneficent has not met this yeast. C. auris is highly transmissible. Not every infection causes illness, but patients who have been colonized may shed the yeast, spreading the disease to more vulnerable people. An invasive infection of say, the blood stream through an IV, can be lethal. The mortality rate is 30% to 60% and it is spreading rapidly and poses a significant global health threat. Though there are some promising cures on the horizon, it doesn’t help that scientific research into epidemics is underfunded right now.

Medicinal fungi, in contrast, are fungi that have healing properties. Medicinal fungi span the gamut from fungi and fungi-based products that cure diseases, to products that work in concert with other medicines to prevent disease, to functional mushroom supplements which may provide more ambiguous health benefits.

The poster child of medicinal fungi is penicillin, which was originally obtained from Penicillium molds. The mold secretes an antibiotic substance as part of its arsenal to ward off bacterial pathogens. That substance was isolated and named penicillin by the English bacteriologist Alexander Fleming in 1928. After that, a generation of scientists purified and stabilized the substance, tested its efficacy in animal and then clinical trials, and developed mass production techniques. It was approved by the FDA in 1945. In the latter years of World War II, allied troops were treated with penicillin, which decreased battlefield deaths; some historians think penicillin was a factor in the allied victory. By 1957 the drug was synthesized (and FDA approved); variations on the molecule made it effective against a wider range of bacterial pathogens. Penicillin antibiotics are thought to have saved 500 million lives.

Other medicinal fungi are used as adjunct therapies, like PSP and PSK, which are polysaccharides extracted from turkey tail mycelium (Trametes versicolor) and lentinan which is derived from shiitake (Lentinus edodes). These are natural compounds with documented antitumor and immunostimulant properties in in vitro and in vivo studies. They are not tumor killers, or at least that’s the current thinking, but rather, they improve the host’s ability to “defend itself from tumor progression.” That means they don’t kill disease like penicillin does, but they may help people not get as sick as they might have had they not used them. These are prescription drugs that are administered orally or intravenously and have been used in the treatment of cancers in Asia for decades. Lentinan, PSP, and PSK are not considered standard-of-care in the USA because the drugs lack large-scale randomized clinical trial data — our gold standard for proving efficacy and safety.

However you can buy lentinan, PSP, and PSK supplements. In the USA, PSK and the like are regulated dietary supplements. Dietary supplements are composed of nutraceuticals and nutrition supplements. Nutraceuticals (a combination of “nutrition” and “pharmaceutical”) are usually food products that are also used as medicine. A product like reishi powder, which you add to your shakes or coffee, is a nutraceutical. Nutrition supplements are things like vitamins and minerals and probiotics, and functional mushroom supplements like Lion’s Mane caps.

Pros and Cons of Functional Mushroom Supplements

Dietary supplements can be prescribed. I take a prescription dose of Vitamin D to slow down bone loss. Hopefully it is helping. But without a clear deficiency that the supplement is able to correct, and measurable responses illustrating the supplement’s efficacy, it’s pretty difficult to determine if a dietary supplement is doing anything at all.

That said, the primary benefit of mushroom supplements is they may act as antigens that provoke immune responses. (The word antigen is short for antibody generator.) Proponents of the healing properties of mushrooms have suggested that our bodies are adapted to respond to fungal beta-glucans with an immune reaction. Here’s the theory: our immune systems have evolved to fight off the airborne pathogenic fungi that are ubiquitous in our atmosphere. When we are exposed to the beta-glucans in those pathogenic fungi, our immune systems kick in. However, when our bodies are exposed to the beta-glucans in nonpathogenic fungi, like shiitake mushrooms, it also triggers our immune system, which may offer an advantage in fighting off disease.

Chemicals in mushrooms, like ergothioneine and glutathione, may play roles in mitigating oxidative stress of cells, which is associated with diseases of aging like cancer and Alzheimer’s. Lion’s mane (Hericium erinaceous) in particular is credited with benefiting aging people due to its purported neuro-regenerative properties. Michael Beug, an environmental scientist who taught many mycologists their craft (including Paul Stamets) used to be skeptical about this mushroom’s health benefits beyond just being a nutritious and delicious food. But now, he told me recently, “I’ve been converted.” Lion’s Mane contains hericenones and erinacine, terpenoids capable of crossing the blood/brain barrier. These terpenoids may support nerve growth.

But any notion that dietary supplements are benign is tricky. Years ago, I took black cohosh supplements to deal with exhausting menopausal symptoms. Black cohosh is claimed to have estrogen-like effects. About a week into it I started to feel really shitty. I went to my doctor who said get the hell off that stuff, it can cause hepatoxicity. But here’s what I learned about supplements from the experience. Black cohosh is not inherently hepatoxic, according to the NCBI, and yet, “products labeled as black cohosh have been implicated in many instances of clinically apparent, acute liver injury, some cases of which have been severe and led to emergency liver transplantation or death.”

The NCBI suggested it’s not necessarily the herb that is the problem, but rather adulterants or mislabeling, like calling something black cohosh when it isn’t. The same thing may be true of mushroom supplements. If someone becomes ill or reactive to a mushroom supplement, it’s not necessarily the mushroom that may be the problem; it could be the manufacturer who is selling it to you.

No surprise there for my magic mushroom loving friends, who remember Shruumz, the “magic mushroom” edibles which turned out to A) not contain fungi, but rather 4-AcO-DMT which is a precursor drug to psilocin, like psilocybin. Though the company indulged in false advertising, that’s not really the problem. The problem was B) the candies included solvents and crap that can make people sick. (Thanks to my colleague Tiney Ricciardi of the Denver Post for her reporting on this.)

A disconnect between what’s in the product and what it says on the label is one issue. Another is interactions. PSP and PSK for example, can affect the efficacy of other medications you might be taking, like antidiabetic drugs. You might not learn about that from the supplement producer. More likely your doctor will say if you are taking this or that medication, go off your supplements. Even something like alcohol can mix treacherously with some dietary supplements, as in the case of a man who consumed reishi powder and booze and developed acute hepatitis. The truth is, no one knows much about the side effects of mushroom-based supplements and co-ingestion with other substances.

The dietary supplement industry does not have the same burden of proof of safety, purity, and efficacy as the drug industry, and the long-term observations that the FDA provides. (I unpacked the FDA regulatory system in an earlier substack.) That’s why the front of your bag of reishi powder says, “helps support immune health.” (So, by the way, does a good night’s sleep.) But the small print on the back says “These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent disease.”

Nor does the FDA weigh in on which is preferable: a mushroom supplement made from the fruit body or the mycelium. They only insist that supplement manufacturers label which source they’ve used.

The FDA does regulate supplements to a degree, but not to the same standards as they regulate foods, cosmetics, and drugs, which means the functional mushroom chocolates you buy—and supplement companies and influencers claim provide health benefits beyond nutrition--have endured less stringent scientific oversight than your Pond’s face cream. FDA regulates the quality, purity, and potency of dietary supplements, but they don’t police companies consistently to make sure they abide by those regulations. Which means there is no guarantee the label matches what’s in the bottle, and the consumer is pretty much on her own.

So, what to do? Tell your doctors you are or are planning to take mushroom supplements. Your doctor may or may not know about mushroom supplement interactions, but at least she can monitor your liver enzymes. In general, supplements made with fruit bodies are considered more potent than products made from mycelium, but not always. PSK is made from mycelium.

Be super careful about the producers. Consumers can check if the supplement has any third-party certification. Look for seals on the bottle from orgs like United States Pharmacopeia, National Sanitation Foundation, and USDA Organic. If the supplement label doesn’t have contact information, preferably a phone number, maybe you shouldn’t take it. Or if the label says it is tested by an “FDA approved lab,” or it is “pharmaceutical grade”—that’s jargon which doesn’t assure you of anything.

Look, I have many friends who make mushroom supplements and I know them to be honorable and careful. I am not trying to piss on an entire industry. I’m just saying if you don’t have the benefit of knowing the producer, then it is in the consumer’s best interest to examine their production.

What about anecdotal data? Doesn’t that count for something?

The science surrounding mushroom supplements is nascent or inconclusive. What exists, and what the industry leans on, are traditional uses, like traditional Chinese medicine, where mushrooms have long been employed. However, how those mushrooms are used in traditional applications and under the supervision of a traditional doctor may be different from how someone might use the mushroom supplements they buy over the counter and self-administer.

The supplement industry also depends on anecdotal data. I have experienced a real pile on, more than once, for suggesting anecdotal data doesn’t rise to the same level as scientific data. There’s nothing wrong with anecdotal data, and you’re not a kook for having faith in it. Anecdotal data is information based on personal accounts and informal observations. The problem is if a group of people report similar responses to a mushroom supplement, but the group isn’t controlled, you don’t really know if it was the mushroom that helped them or the maple syrup they put on their pancakes in the morning.

That said, there are different types of anecdotal data. Maybe least persuasive, in my view, are individual stories claiming cures from the mushroom—like the Turkey Tail cured my cancer narrative. I don’t doubt it, I just have no reason to think it will work twice. More persuasive are large data sets where lots of people share similar testimonies about their experiences. For example, many people on the Clusterbusters website shared testimonies from cluster headache sufferers who found using psilocybin helped mitigate their headaches. That caught the attention of researchers who thought, Hmmm, let’s design a study to see what is happening here.

Anecdotal data can lead the science. A large body of anecdotal data is compelling, but it is not science. A scientific study will try to show results that are reproducible, and its evidence can be objectively verified. But without reproducibility, the validity of anecdotal data is…well, anecdotal.

I was gratified to read this piece in the NYT the other day (there’s a paywall—sorry about that folks), which quotes the mycologist David Hibbett. He said that when it comes to mushroom supplements, “the popular imagination is way ahead of where the science is.” He’s right. Mushrooms have captured our collective imagination and that’s led to all kinds of wishful thinking about how they might benefit our health. But I would add that many of us are not savvy about the subtleties of supplement and drug regulation, and that helps create a vulnerable consumer, too. The supplement industry isn’t doing anything untoward (unless they are selling polluted or mislabeled products). But they may benefit when you don’t know there is a difference between what they are and what they are not.