It’s an eye-catching title, I’ll admit. But the links are quite real and further research may guide medicine in new directions of cancer prevention and treatment.
It all starts in your gut microbiome, the totality of microorganisms–bacteria, viruses, protozoa, and fungi–present in your gastrointestinal (GI) tract, mouth to anus. Until recently, researchers and clinical physicians alike paid virtually no attention to the microbiome and the ways in which it contributes to health or disease.
Infectious disease specialists were interested in diseases of the microbiome (the various forms of diarrhea, for example), but no one ever talked about what it meant to have a healthy balance of bacteria in your gut. Probiotics, like supplements in general, were considered a scam.
Fungus among us
Ironically, the general public became aware of microbiome issues years before medical doctors. This came about partly due to a book written by a small-town general practitioner, William Crook, MD, called The Yeast Connection. He had noted a range of symptoms in people who had taken antibiotics for long periods and he attributed them to an overgrowth of a fungus, or yeast (not the yeast of bread, by the way), called Candida albicans.
It’s hard to describe the hostility of conventional physicians toward the book and Dr. Crook’s ideas. I’ve written several articles, including this one, about this pseudo-controversy. In some states, medical boards actually tried to encourage local legislatures to rescind the medical license of any physician who diagnosed candida overgrowth.
Even to this day, 33 years after the book was published, patients still encounter doctors who think Candida is a fad diagnosis connected somehow to chiropractors (probably because they were the first to take it seriously).
However, solid medical research has proven these Candida naysayers quite wrong. Mayo Clinic first reported Candida (and other fungi) as a cause of chronic sinusitis in 1999. Several studies during the past few years have linked Crohn’s disease (an inflammation of the intestine) with candida. In both situations, taking an antifungal and balancing the gut microbiome improved, and often healed, the conditions.
So how does cancer fit in to this?
A statistical analysis published in 2017 found that people with recurring Candida infections had a significantly higher incidence of all types of cancer than the general population. Why this should be so was not completely understood, but generally Candida infections occur in people with weaker-than-normal immune systems. It’s also pretty well accepted that a healthy microbiome generally reduces your cancer risks, especially for esophageal and colon cancers.
Dandruff, also called seborrheic dermatitis, affects a full 50% of all adults and is caused by a yeast-like fungus called Malassezia. While Malassezia is usually found spread over our entire bodies, it’s also one of the millions of species of microorganisms in our gut microbiome.
In a report published in last week’s Nature, researchers discovered Malassezia growing in the pancreatic cancers of lab mice and also in samples of human pancreatic cancers. Moreover, when given antifungal medication, the mouse cancers started shrinking, starting to grow again when the Malassezia was reintroduced into the pancreas.
This means intestinal Malassezia now joins Candida as a cancer risk. This research seems to have unearthed what might be responsible for pancreatic cancer, one of the most deadly cancers in humans. In the future, antifungals may actually be an important treatment.
An interesting sidelight: the best treatment for dandruff, or any of the skin fungal infections, is shampoo containing the element selenium (an ingredient in Selsun Blue). It works as an antifungal and, used regularly, will keep your dandruff at bay. In addition, selenium taken by mouth is a popular supplement, promoted as both an antioxidant and immune booster. Selenium is always listed among the top supplements to take if you have cancer, though there’s not much solid research on this.
Maybe, just maybe, oral selenium prevents/helps treat cancer not because it’s an antioxidant, but because it’s an antifungal.
This very important paper linking the dandruff fungus to pancreatic cancer reminded me of a patient I had years ago. He was a very healthy, middle-aged man who developed inflammation of his gallbladder while on vacation. What should have been a simple operation to remove his gallbladder went very badly and he spent a month in the hospital on high doses of intravenous antibiotics, with external drains from his liver and pancreas. That he survived at all was something of a miracle.
About three years later, he was diagnosed with cancer of the pancreas. This time, luck and surgical skill were on his side. The cancer was completely removed and he’s still very much alive today. He and I always felt that somehow the bungled gallbladder surgery set the stage for the pancreatic cancer, but none of the cancer specialists would acknowledge a link. We didn’t buy “just a coincidence.”
Now, years later, it all comes together. The antibiotics totally disrupted the balance of his microbiome, allowing overgrowth of both Candida and Malassezia. The multiple drains disrupted the natural anatomic barriers that protected his pancreas and it’s likely that copious amounts of Malassezia poured in, proliferated, and triggered the cancer growth.
Sorry for the length of this Health Tip, but if the New York Times can run a front-page story about the fungus-cancer link, so can I!
In the meantime, you’ll want to work mightily to maintain a healthy microbiome. If you need some help, review this Health Tip carefully. Then stop by our apothecary and we’ll get you started.
David Edelberg, MD