Review finds intake of probiotics improves numerous factors in people with colorectal cancer

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.


Apply What You've Learned: Colorectal cancer

  • It has been estimated that as many as 70% of colon cancers may be preventable through diet and lifestyle.1
  • Maintaining a regular level of physical activity, consuming a generous amount of fruit and vegetables, avoiding processed meats and high fat, low fiber foods; maintaining a healthy weight, consuming alcohol only in moderation and not smoking can lower the risk of developing colorectal cancer.2,3
  • Curcumin, which occurs in the spice turmeric used in Indian cuisine, has shown an ability to interfere with a number of cell signaling pathways involved in cancer.4 Cell and animal studies have shown a protective effect for curcumin against colorectal cancer.5
  • The American Cancer Society and the United States Preventive Services Task Force now recommend that screening for colorectal cancer among people at average risk for the disease should begin at the age of 45.6,7 Compared to other screening methods, screening for colorectal cancer with a colonoscopy has the advantage of enabling the removal of polyps (which may be precancerous) at the same time the patient is undergoing their examination.


  1. Giovannucci E et al. Gastroenterol Clin North Am. 2002 Dec;31(4):925-43.
  2. “What Are the Risk Factors for Colorectal Cancer?” Division of Cancer Prevention and Control; Centers for Disease Control and Prevention. 2021 Feb 8.
  3. McNabb S, et al. Int J Cancer. 2020 Feb 1;146(3):861-873.
  4. Anand P et al. Cancer Lett. 2008 Aug 18;267(1):133-164.
  5. Pricci M et al. Int J Mol Sci. 2020 Mar 29;21(7):2364.
  6. “American Cancer Society Guideline for Colorectal Cancer Screening.” American Cancer Society. 2020 Nov 17.
  7. “Colorectal Cancer: Screening. U.S. Preventive Services Task Force. 2021 May 18.

Featured Life Extension Magazine® Article

The Vitamin D-Magnesium Connection, by Marsha McCulloch

Vitamin D and magnesium are two nutrients whose critical roles in numerous physiologic processes have been brought to light during the past few decades. What is less well known is that magnesium is essential for the conversion of vitamin D into its active form. If this conversion does not take place, vitamin D remains inactive in the body.

Magnesium also enables vitamin D to be transported through the blood and activates vitamin D receptors needed for the cells to utilize the vitamin. Vitamin D enhances the absorption of magnesium in the intestines, particularly among individuals who have low levels of this important mineral.

Both vitamin D and magnesium are needed for bone, muscle and heart health, along with other nutrients.

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