Polyphenols and microbiota: allies against colon cancer

Colon cancer is one of the most common cancers in the world, and its prevention can begin on the plate.

Science is discovering that what we eat not only feeds our cells, but also the millions of microorganisms that live in our gut, the intestinal microbiota, which plays a fundamental role in digestion, immunity, and, as has recently been discovered, in the prevention of certain types of cancer.

Illustration of plant-based foods (fruits, vegetables, and herbs) and the gut.

Polyphenols and the gut

Among the nutrients with the greatest preventive potential are polyphenols, bioactive compounds present in fruits, vegetables, and plants. They are known for their antioxidant and anti-inflammatory properties, but they also appear to have a direct action on the microbiota, helping to maintain a healthy intestinal environment and protect against inflammatory and tumor-causing processes.

Gut Microbiota and Cancer

Our gut is populated by a community of microorganisms that influence our digestion, immune system, and even our mood. When this community becomes unbalanced, dysbiosis occurs, a phenomenon that has been linked to the development of colon cancer.

In people with CRC, an increase in pro-inflammatory bacteria such as Fusobacterium nucleatum and a decrease in protective bacteria such as Bifidobacterium and Lactobacillus has been observed. This imbalance can increase inflammation and damage the intestinal barrier, promoting cancer progression.

How do polyphenols help?

Although polyphenols are not fully absorbed in the small intestine, when they reach the colon, bacteria transform them into more active metabolites that:

  • Promote the growth of beneficial bacteria.
  • Produce short-chain fatty acids (such as butyrate), which nourish colon cells, reduce inflammation, and help stop the growth of tumor cells.
  • They act directly on immune cells, strengthening defenses against tumors.
Illustration of an Erlenmeyer flask surrounded by plants

And what foods contain them?

As we've already mentioned, polyphenols are found in plant-based foods, and there are many different types. Depending on the food, some predominate over others, promoting certain antioxidant, anti-inflammatory, or prebiotic functions depending on their profile.

  • Resveratrol: grapes, red wine.
  • Apigenin: parsley, chamomile, celery.
  • Quercetin: onion, apple, black tea, salicornia.
  • Curcumin: turmeric.
  • Ellagitannins: red fruits, nuts.
  • Hydroxytyrosol and tyrosol: extra virgin olive oil.

A diet rich in these polyphenol-rich foods may have a protective effect.

What does science say?

According to a review published in July 2025 in the journal Foods, polyphenols have a real impact on intestinal health, especially in the context of colorectal cancer. Evidence collected from animal models and cell cultures shows that these compounds:

  • Promote a more balanced microbiome, favoring the growth of beneficial bacteria such as Lactobacillus and Bifidobacterium, and reducing potentially pro-inflammatory species such as Fusobacterium nucleatum.
  • They help restore the intestinal barrier, strengthening the junctions between the epithelial cells that line the intestine, preventing toxins and harmful bacteria from passing into the bloodstream.
  • They stimulate the production of protective metabolites, such as butyrate, a short-chain fatty acid key to colon health, which has anti-inflammatory and anti-tumor properties.
  • They modulate the immune system, reducing the expression of genes related to chronic inflammation and inducing a more efficient response to tumor cells.

Furthermore, studies with specific polyphenols such as curcumin, quercetin, resveratrol, and apigenin have shown that these compounds can:

  • Inhibit the growth of cancer cells.
  • Induce apoptosis (programmed cell death) in tumor cells.
  • Block molecular pathways involved in inflammation and uncontrolled proliferation.

Conclusion

Polyphenols are found in everyday, accessible foods. If you want to take care of your gut microbiota and, thereby, help prevent diseases like colon cancer, here are some specific actions you can incorporate into your daily routine:

  • Eat more plants: fruits, vegetables, legumes, nuts, olive oil.
  • Avoid high-fat, low-fiber diets, as they promote dysbiosis.
  • Incorporate fermented foods such as yogurt, kefir, or sauerkraut, which combine well with the effects of polyphenols.
  • Think of your microbiota as another organ that also needs to be nourished.
Illustration of fruits and herbs and a gut

Written by Sara Montaner. We rely on AI technology.

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