Beans Improve Gut Health of Colorectal Cancer Survivors

Colorectal cancer survivors who incorporated beans into their diet experienced gut health improvements, according to recent research.

Participants who added a cup of navy beans to their meals throughout the day had improvements in their gut microbiome during the Beans to Enrich the Gut microbiome versus Obesity’s Negative Effects, or BE GONE, trial from The University of Texas MD Anderson Cancer Center in Houston, findings of which were published in the journal eBIOMedicine.

“Adding one cup of navy beans to the diet on all or most days of the week was a safe, scalable dietary strategy to modulate the gut microbiome of high-risk patients, who may be unwilling or unable to sustain more dramatic changes to their usual dietary pattern without substantial support,” study authors wrote. “Given the tolerable side effect profile for a population with a history of bowel lesions, beans should not be intentionally avoided.”

The addition of beans to participants’ diets modulated markers linked to obesity and disease, with changes associated with cancer prevention and improved treatment outcomes, including increased alpha diversity, or beneficial bacteria, and decreased pathogenic bacteria, according to a news release from MD Anderson Cancer Center.

“Observing a shift in microbiome diversity with diet intervention alone is rare, and this study underscores the ability of a readily available prebiotic food to bring about such changes,” said corresponding author Carrie Daniel-MacDougall, an associate professor in the department of epidemiology, division of cancer prevention and population sciences at MD Anderson Cancer Center, in the news release. “Over the course of eight weeks, there was an improvement in participants’ gut health, marked by an increase in beneficial bacteria, which wards off the harmful bacteria.”

The BE GONE trial included the participation of 48 patients over the age of 30 who met obesity criteria via either their body mass index (BMI) or their waist size, and who had a history of bowel lesions such as colorectal cancer (75% of participants) and/or high-risk, precancerous polyps of the colon or rectum, MD Anderson Cancer explained in the release.

Patients either followed their standard diet or added a cup of organic, canned, pressure-cooked white navy beans to their daily food intake, with participants preparing their own meals and providing stool and fasting blood samples every four weeks.

“This highly accessible and adaptable prebiotic food intervention … and was sufficient to enhance the diversity and composition (of) the gut microbiome within eight weeks with parallel shifts in host metabolites, immune and inflammatory biomarkers,” researchers wrote in the study.

Researchers said no serious side effects from the navy bean regimen were reported, but patients who returned to their usual diet without beans “was quite striking, with reversals in favorable changes in bacteria and host metabolites within four weeks.”

Daniel-MacDougall noted in the release that beans offer gut-supporting fiber, amino acids and other nutrients which can in turn support beneficial bacteria in patients’ colons, and potential gastrointestinal side effects from eating beans can be mitigated by preparing them properly and consuming them consistently. However, she also advised that patients consult with a doctor before attempting to increase their bean intake.

“The beans did not appear to induce gut inflammation or seriously impact bowel habits, which is crucial for (colorectal cancer) survivors and patients,” Daniel-MacDougall said in the release. “However, once participants stopped eating the beans, the positive effects faded quickly, highlighting the need to educate patients on how to maintain healthy habits.”

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