Daniel Lemire's blog

, 3 min read

Are fungi making us sick?

Fungi are everywhere. Yeasts, molds, mushrooms. We eat them. They live on our skin.

But are they making us sick?

That’s a theory strongly held by Martin Laurence. Martin created his own lab (Shipshaw labs) and even wrote a book on the topic. He reports that psoriasis and inflammatory bowel disease are both strongly associated with fungi. It appears that we all get fungal infections when we become sexually active. For men, this fungal infection could migrate to the prostate. What if you are never sexually active? Catholic priests, who are maybe less likely to have been sexually active, have an exceptionally low rate of prostate cancer. If you fail to see how fungus could cause cancer, consider that cervical cancer in women is strongly related to a viral infection. That is, “bugs” can give you cancer.

What is well known is that cancer patients suffer from fungal infections. However, the fungal infection is generally viewed as the consequence, not the cause of the cancer.

So if Martin is right, why is this not known, or at least under investigation? One problem, according to Martin, it is that it is hard to test for some asymptomatic fungal infections or, at least, researchers and hospitals might be ill-equipped to do so. You may need to use something fancy like DNA analysis… not something your average doctor can do.

Martin is especially interested in Malassezia. Malassezia lives on our skin, eating our fat, and causes dandruff and some forms of eczema. It seems able to infect your prostate as well as your gut. There is no obvious reason why it could not infect other organs, including the brain. In fact, there is a theory that Alzheimer’s might be caused or triggered by fungal infections.

That’s all a bit freaky if you ask me.

Ok. So what do we do to test Martin’s theory out? The obvious path forward is to try to clear the fungal infections. Martin likes itraconazole a lot: it is a cheap and well-tolerated drug. It won’t cure cancer, but if you could flush out fungal infections, you might be able to prevent or delay some diseases. In a short note, some doctors from the Mayo clinic reported that treatment with itraconazole was able to effectively fight against Crohn’s disease.

My understanding is that Martin believes that what often passes as an autoimmune disease (e.g., psoriasis) might actually be a reaction to fungi. That is, most of the time your body does not attempt to fight off fungus, but if somehow forced to do so, it will start waging a losing war, hurting your own body.

Obviously, as you grow older and especially if your immune system becomes less effective, you are more likely to suffer from a fungal infection. Thus it is plausible that fungi could harm older people and be related to age-related diseases.

The main reason I find Martin’s theory appealing is that, if he is even partially correct, there might be dirt-cheap therapies that help many of us remain healthier. It seems that Martin is ready to move to clinical trials. Hopefully we shall soon find out whether there is substance to this theory.

Appendix: Martin had more pointers:

  1. Kellermayer (2012) found an association between Malassezia in gut biopsies and Crohn’s disease in teenagers.
  2. Kanda (2002) found an association between a response to Malassezia and psoriasis.
  3. Squiquera (1994) found an association between antibodies against Malassezia and psoriasis.
  4. Lober 1982 induced a psoriasis lesion by applying dead Malassezia to the skin of 10/10 genetically susceptible patients.
  5. Rautemaa (2007) and Delsing (2012): chronic Candida infections increase oral cancer risk. Unfortunately, we are finding that Malassezia chronically infects the breast (Boix-Amaros 2017).