A systematic review of randomized trials that appeared on May 24, 2021 in Nutrition Reviews concluded that probiotic intake is associated with a number of beneficial effects in colorectal cancer (CRC) patients with any stage of the disease.¹

Probiotics are living microorganisms (typically bacteria, but also yeasts such as Saccharomyces spp.) that when consumed in adequate amounts have been shown to benefit the health of the body. Consuming probiotics may benefit gut health, nutritional status, immune function and even brain health. Prebiotics are foods (often non-digestible oligosaccharides such as xylooligosaccharides) that nourish probiotics and the healthy bacteria in the gut and support their maintenance within the body.

For their review, researchers at the University of Malaya in Kuala Lumpur, Malaysia screened numerous databases, finding 23 randomized, controlled trials that met the criteria for their review. The studies included a total of 2,457 participants who had undergone surgery for various stages of CRC. A total of 1,403 participants received probiotics and 1,054 participants served as controls.

Of the included studies, 12 trials evaluated the effects of a mixture of probiotics, 7 trials used synbiotics (which combine prebiotics with probiotics), 3 trials used single strains of probiotics and 1 trial used the fermented milk beverage kefir. The probiotics most commonly administered included Bifidobacteria and Lactobacillus varieties. Six of the included trials analyzed the effects of probiotics on gut microbiota, 4 trials studied their effects on the immune system and inflammatory biomarkers, 18 examined postoperative complications, 7 evaluated length of hospital stay, 4 measured quality of life improvement, 2 assessed tumor growth and tumor stage development, and mortality was assessed in two trials.

The researchers found probiotics improved gut microbiota diversity, and in one study also reduced amounts of a bacteria shown to be present at higher levels in patients with CRC. In multiple studies, there were fewer postoperative infection complications, less proinflammatory cytokine production and better quality of life occurred among participants who took probiotics compared to the control groups. Probiotic intake was also found to decrease chemotherapy side effects, decrease tumor growth, improve surgery outcomes, shorten hospital stay and lower risk of mortality.  

“The use of probiotics and synbiotics provides numerous health benefits, as seen in this systematic review,” the authors wrote. “The findings in this systematic review also highlight the importance of preoperative administration of probiotics or synbiotics as well as postoperative administration of probiotics, especially for patients with colorectal cancer who have invasive surgeries and are on a chemotherapy regimen.”

In closing, they note “In the future, the use of probiotics against colorectal cancer should be able to broaden and become more personalized in treatment of patients with colorectal cancer. Dietitians, nutritionists, and general practitioners should also recommend intake of probiotic[s]…more frequently to reduce the risk of colorectal cancer development, and the administration of probiotics should commence at the first diagnosis of colon polyps.”

1. Dikeocha IJ et al. Nutr Rev. 2021 May 24.