There is definitely one thing that is clear: the bacteria in your gastrointestinal tract play a huge role in your overall health, especially your immune response to cancer. Don’t think of these microorganisms as “invaders”, they are “little workers” in the factory that is your body. It is these “little workers” that are either directly, or indirectly interacting with your immune cells, affecting how they respond to situations. In regards to cancer, it is frequent that patients have a disruption of their normal balance of microbes, called “dysbiosis.” The question is, which came first? Cancer or dysbiosis? The answer is unclear, but it could be all of the above.
Certainly many things associated with cancer, chemotherapy, radiation, and other medications such as antibiotics can have a negative effect on the microbes in your intestines. However, it would also not be surprising that cancer could actually produce substances causing dysbiosis, further helping it evade the immune system. This really becomes a difficult situation. So, how do you overcome this? Probiotics? Well, maybe not. From what we know at this point, diversity is the key. The more diverse bacteria you have, the better. Sounds great, but how do you get more diverse bacteria?
First, and most important, a high-fiber diet. People who eat more fiber tend to have a more diverse microbiome. A diet with lots of plant-based foods is a great option. I know what you are thinking, how about I just take some probiotics? It turns out that taking probiotics or at least too much, the wrong types or whatnot, actually reduced diversity of the microbiome and also seems to negatively affect immunotherapy. The one problem with probiotics is that there are many types without much standardization. One brand of probiotic, which has been shown very effective in treating inflammation of the colon, actually worsened cancer in the animal model.
In general, you can think of autoimmune diseases and cancer being in opposing spectrums. If something helps autoimmune diseases, then it probably is not helpful for cancer immunotherapy. There are always exceptions, but this is a generalization. In cancer immunotherapy, you need the immune system to attack cancer. Cancer arises from your cells, so it is part of your body. If you want your immune system to attack part of your body, you are asking to create an autoimmune condition. I think you get the idea now. As I had mentioned, diversity of the microbiome is the most important aspect to enhancing immunotherapy, at least that we know at this point.
If you supplement with too many probiotics, you are “gentrifying” your GI tract, replacing the more diverse bacteria in the intestines with the lack of diversity of probiotics. I know what you are going to say, but my probiotics has 400 billion organisms. Sure, it may, but it is 400 billion of only a handful of different types; not very diverse. This being said, there are certain specific bacteria that could be supplemented to your microbiome, just to enhance them, but not to overwhelm and take over. The bacteria that have shown to be beneficial are Bifidobacterium breve and longum. Studies show that these are essential for the function of PD-1 inhibitors, which of course are the most widely used immunotherapy. Though there is much that we don’t know, it is my opinion that the trick is to just supplement. Take a probiotic that has more of these types of bacteria, like a SuperBifido or 5 Strain Bifido. I would suggest not taking too much though, probably just once a day, three times a week. Hopefully that way you provide the needed bacteria, but not negatively affect the diversity.
What other bacteria can help immunotherapy work better for cancer? Well, one of the other more important ones is called Akkermansia muciniphila. Great! Run out and buy a probiotic with this. Sorry! This one though is not available as a probiotic. I am not sure why, but most likely is that it does not survive long enough. However, all is not lost, there are things you can take to boost the numbers of this bacteria. I explain this in more detail in my book, but to cut to the chase, supplement wise, it is cranberry or rhubarb extract. In addition, the prescription diabetic medicine Metformin also seems to increase A. muciniphila and have positive effects on the microbiome. Metformin is commonly used as an off-label cancer treatment, this just further supports that. Supplementing with Omega 3 also seems to increase the diversity of bacteria in the GI tract. This is certainly an easy addition as a supplement.
I must mention that one study showed that patients that eat one serving of cashews a week had a better response to immunotherapy as compared to patients who didn’t. This is probably related to anacardic acid found in cashews. Anacardic acid has anti-cancer properties and seems to have positive effects on the microbiome. The only caution is that cashews have a high amount of lectins, which in higher amounts may be harmful to the intestines. So, I stress again, the study stated just one serving a week. Maybe direct supplementation of anacardic acid would be useful, but I have not found much in the way of people selling it as a supplement.
In addition, I would make sure to avoid unneeded antibiotics. Sure, it happens in cases when an antibiotic is needed and can save your life. However, for more minor things that may not even be caused by bacteria, or to be used to prevent an infection, certainly discuss with your doctor the concern. We know from studies that antibiotic use just prior to and during immunotherapy will potentially decrease the effectiveness. If you do have to take one, know that taking probiotics after has actually shown a slower recovery of the microbiome than taking nothing. I know, go figure.
I think it is worth mentioning that there is microbiome testing available. There are some that are more geared toward the results needed for immunotherapy. I think it is reasonable for patients to get this testing. Especially if you have failed immunotherapy previously. Don’t let the microbiome be the reason that immunotherapy failed. Evaluate it and address it appropriately.
Now, what if you have done everything I have mentioned and your microbiome still is not in order and you failed immunotherapy? Well then you go to your #2 option, and I literally mean number two. In my opinion, that is when a fecal microbiota transplant (FMT) may be in order. Yes, it is what it sounds like, taking stool material from a healthy person, maybe even someone who has been cured by immunotherapy previously and transferring it to the GI tract of the cancer patient. This type of procedure is normally used for Clostridioides difficile infection and is not approved in the U.S. for other conditions. Studies have supported this, but it will not be easy to obtain, especially in the U.S. I must mention that in the U.S., during a clinical trial, there was a death associated with FMT in 2019, from transmitting resistant bacteria. This was in a patient with a weakened immune system and an isolated and rare case, which may be prevented in the future with proper screening.
I trust that this information on the microbiome and cancer immunotherapy is helpful to you. Please follow my blog and videos, as there will be many updates in this rapidly advancing field. As always, discuss any of these suggestions with you doctor before trying, to make sure they are right for you.