When Chemotherapy Damages our Gut

Coming off of birth control with acne-prone skin

It’s no surprise that chemotherapy can wreak havoc on our digestive system. In fact, some of the most notorious side-effects of chemo are a direct result of irritation and damage to our gut! While our gut provides the physical space and movement, it is our microbiome determines how protected, active, and supported all the functions of our gut are. When we’re healthy, our microbiome is diverse and balanced, unfortunately this complex system is vulnerable to damage. Chemo drugs, although effective, can dramatically reduce the diversity of our microbiome and shift the types of bacteria present.

Aside from a poorer functioning gut, why is this a problem when fighting cancer? Well research has started looking directly at the consequences chemotherapy has on the microbiome, and it is now being suggested that the microbiome may influence how well our bodies respond to chemotherapeutic drugs (more on that in a later post!). The biggest problem comes from this overall change in the diversity, resulting in an increased number of “bad” bacteria, while reducing the presence of “good” bacteria.

So what is chemo really doing to my microbiome?

Well, one study looked at the composition of poop before and after chemotherapy. Researchers found that not only was the type and diversity of bacteria dramatically different after chemo, but noted that this altered microflora helped to create a more inflamed gut environment. Inflammation in the GI tract can make you more vulnerable to infections, as well as bring out symptoms similar to what we see with inflammatory bowel disease (think cramping, bloating, diarrhea, low appetite).

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Diving even deeper, another group of researchers looked at the effects of chemotherapy on the microbiome of 28 patients receiving chemotherapy to prepare them for stem cell therapy. Looking at the genetic signatures of their gut bacteria prior to and following chemotherapy, they found that the chemo had a profound disruptive effect on the intestinal microbiome, resulting in three significant changes:

  1. Reduced bacterial diversity. This decrease in the variety of bacteria is associated with intestinal inflammation and puts our gut mucosa at increased risk of colonization and invasion by pathogenic (bad) bacteria.

  2. Changes in metabolic pathways. These changes may be happening in response to the oxidative stress being placed on the intestinal microbiome and lead to a reduced ability to stop inflammation.

  3. Increased intestinal permeability + altered mucous layer composition. When the mucous layer that protects our gut tissue is compromised, our gut is more vulnerable to damage. This ultimately results in a higher risk of bacteria slipping through our damaged gut, leading to infection (a fairly frequent complication of chemotherapy).

What can I do about this?

So how do you protect your microbiome and digestive tract during treatment, and heal it after your system has been disrupted by chemotherapy? Research has not caught up enough to tell us exactly which probiotic strains are most effective, but we do know that the microbiome needs variety and diversity. Research is showing us which bacteria can help protect our gut, and which ones are causing damage. And proving to us that a good, multi-strain probiotic is not only reasonable to help restore the gut microbiome after treatment, but can be used preventatively, alongside digestive enzymes, to help protect the gut from damage. As a note, your care team may caution you about the risk of probiotics causing infection during chemotherapy, and this concern should not be ignored. For this reason always consult with your Naturopathic Doctor before you consider adding this in during treatment. Seeing a Naturopathic Doctor allows you to be well-informed on what products to avoid, as well as when you should be taking probiotics during your cancer treatment, so you’re not placing yourself at greater risk, and only reaping the fantastic protective effects of these little probiotic helpers.

Finally, let’s not forget the most obvious way of helping support the gut, our food! A few things to consider as you recover and heal your digestive system include:

  1. Nuts. Not only do these help to add fats, fiber, and a little protein to our diet, but pistachios in particular seem to not only enhance the microbiome but are also showing chemoprotective effects (potentially helping to reduce colon cancer risk). This is all thanks to their B vitamin, polyphenol, and dietary fiber content.

  2. Berries. High in antioxidants, these tasty fruits have been shown to increase bacterial diversity and especially help to increase the amount of good bacteria in the gut.

  3. Fibre. Foods high in fibre can help optimize our bacterial diversity, as fibre is fermented by gut bacteria which helps control gut inflammation.

  4. Increasing your vegetable intake. No matter the type of diet studied, significant benefits are always shown to be a direct result of vegetable intake. Research has shown the most improvement in regards to increasing microbiome activity, overall diversity, and the prevalence of those “good” bacteria we love so much.

dr hayhlee clarence

Ready to make a change?

Dietary changes are a fantastic way to help yourself become healthier without too many added costs and complications.  If you are in search of more direct and personalized ways to heal your gut while going through chemotherapy don’t be afraid to reach out and ask. We can help.

In support of your health,

Dr. Hayhlee Clarence, ND