The scientific mystery of mushrooms in the world of pet supplements

Doggie Herbs is one of several specialty brands now offering medicinal mushroom supplements for dogs. It began integrating mushrooms into its products in 2016, according to company founder Sean Russell. They were getting an overwhelming number of requests for supplements to boost immunity and prevent cancer, and due to his experience with mushrooms in herbal medicine for humans, he suspected that certain mushrooms could fit the bill.

Supported by cancer research
Indeed, research published in the late 1990s and into the 2000s indicated that medicinal mushrooms may prove beneficial to dogs. One study indicated that dogs who received a mushroom-based supplement while undergoing chemotherapy had fewer symptoms and overall better quality of life than those that did not.

Russell zeroed in on the same compound identified in the research: beta-glucans, a specialized form of fiber found in certain cereals, yeasts and mushrooms. He eventually secured appropriate suppliers and manufacturers, and the mushroom-based supplements were an instant hit with customers. Doggie Herbs now offers two mushroom-only supplements as well as a herb-and-mushrooms blend.

“Our mushroom products are the most popular products that we sell,” Russell explains. The buzz around mushrooms high in beta-glucans, such as Turkey Tail, and their purported cancer-fighting qualities drive consumers to the internet to learn more and find mushroom supplements for their dogs.

Complicated science
But while public excitement about the potential of mushrooms has only grown since the first research trials suggested mushrooms had potential cancer-fighting benefits, the science has become more complicated, according to Matt Cleaver, an independent researcher and consultant who studies medicinal mushrooms.

Cleaver was one of the contributing researchers in the trials connecting beta-glucans to improved outcomes during chemotherapy. The exciting thing about beta-glucans from mushrooms, he says, was that they didn’t just enhance the immune system or suppress it (which can cause too much inflammation or, at the other end of the spectrum, leave patients open to infection). Instead, the mushrooms appeared to actually modulate the immune system, turning off unhelpful inflammatory responses and boosting the ability to fight infection at the same time.

However, as often with research into natural medicine, the study was plagued with many problems, especially the presence of diverse variables that complicate and could interfere with the end results. “When you’re testing a drug, you’re usually working with a single chemical compound that is suspected of having a particular effect. This makes it relatively easy to set up an experiment; one group of test subjects gets the chemical, the other doesn’t. If the desired results show up in one group but not the other, the chemical works,” Cleaver explains. But natural remedies don’t benefit from this simplicity – and mushrooms are particularly difficult to research. “Forget specific chemical compounds; in some cases, scientists haven’t even settled the debate about what separates one species of mushroom from the next.”

Fiber composition in mushrooms
Mushrooms also tend to contain specific beta-glucans not present in other sources of fiber such as cereals, but the exact composition of fibers varies from one mushroom to the next. So as additional trials tried to narrow down and isolate key beta-glucans, the results became less dramatic and raised questions about whether beta-glucans were really the compound responsible for the initial results.

According to Cleaver, this isn’t to say that the mushrooms aren’t effective at modulating the immune system. “There’s ample research to support that claim. It’s even possible the beta-glucans are still part of the equation. Achieving immune modulation may just require a specific combination of beta-glucans,” he says.

“Or perhaps the fibers interact with other compounds in the mushroom, or even elsewhere in the dog’s diet. We know the mushrooms work, but why remains a mystery. But ultimately, consumers may not mind. If they notice the quality-of-life difference, even if they can’t quantify it as impeccably as with other medicine, they’re probably still going to buy it,” he concludes.