How Chemotherapy Changes Our Gut

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Anyone who has been through chemotherapy knows how much havoc it can wreak on your gut. In fact, some of the most notorious side-effects of chemo are a direct result of irritation and damage to our digestive tract! So, while our digestive tract provides the physical space and movement when we are breaking down food, it is our microbiome that determines how protected, active, and supported all the functions of our gut are. A healthy microbiome is diverse and balanced, unfortunately chemotherapeutic 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!). What we know currently is that 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?

It cannot be forgotten that the research we are getting on the microbiome is being done by researchers working directly with stool samples. So here’s a quick thank you to all you who dug around and examined our poop!

So what have they found out?

In one study where they looked at fecal (poop) composition 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 created a more inflamed environment in digestive tract. AND…inflammation in the gut 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).

Got any more info?

Well, another group of researchers looked at the effects of chemotherapy on the microbiome of 28 patients receiving chemotherapy in preparation for stem cell therapy. They examined the genetic signatures of everyone’s gut bacteria prior to and following chemotherapy, and found that the chemo had a profoundly 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. It is suspected that these changes may be happening in response to the oxidative stress placed on the intestinal microbiome during treatment, leading 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 digestive tract is more vulnerable to damage. This ultimately results in a higher risk of bacteria slipping through our damaged gut, which can cause 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 is not yet able to tell us exactly which probiotic strains are most effective, but we do know that the microbiome needs variety and diversity. Not only has research shown us which bacteria can help protect our gut, and which ones can damage it, it’s proving to us that a good, multi-strain probiotic is not only reasonable to help restore our microbiome after treatment, but can be used preventatively, alongside digestive enzymes, to help protect our digestive tract 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. Your ND can ensure you are well-informed on what products to avoid, and when you should be taking probiotics during treatment. Having a clear understanding of when and what to take makes sure you are not placing yourself at greater risk, so you can just benefit from 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! Consider the following as you recover and heal your digestive system:

  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 to protect against cancer (potentially helping to lower colon cancer risk). This is all thanks to their B vitamin, polyphenol, and dietary fiber content.

  2. Berries. These tasty fruits are not only high in antioxidants but have been shown to increase bacterial diversity and can help increase the amount of good bacteria in our gut.

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

  4. Increasing your vegetable intake. No matter which diet we study, significant benefits are always shown to be a direct result of vegetable intake. Research keeps telling us that the most significant improvement to our microbiome activity, diversity, and prevalence of the “good” bacteria we love so much comes directly from all those colourful vegetables.

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 hesitate to reach out and ask.

In support of your health,

Dr. Hayhlee Clarence, ND