Yogurt could reduce the risk of a specific type of colon cancer by 20 percent, according to a new study that tracked more than 130,000 health care professionals for decades.

People who ate at least two servings of yogurt weekly had significantly lower rates of colorectal cancer through changes in the gut.

The findings provide evidence of yogurt’s potential role in cancer prevention, according to the study authors.

“Our study provides unique evidence about the potential benefit of yogurt,” corresponding author Dr. Shuji Ogino, chief of the molecular pathological epidemiology program at Brigham and Women’s Hospital, said in a statement.

Two or More Servings

The study, recently published in Gut Microbes, examined data from studies that followed participants for about five decades.

The study didn’t find a strong enough link between yogurt and overall colorectal cancer risk to be considered statistically significant (meaning that the result could have been because of chance). However, they did find that people who ate at least two servings of yogurt a week had a 20 percent lower rate of a specific type of tumor located on the right side of the colon that tests positive for Bifidobacterium bacteria.

Right-sided tumors often cause fewer noticeable symptoms such as bleeding, leading to later diagnosis when the cancer has already spread and therefore worse survival outcomes.

Participants reported their yogurt intake (plain and flavored) every four years using a detailed food questionnaire. However, the study doesn’t specify whether one type offered a greater benefit against colorectal cancer.

Bifidobacteria are beneficial bacteria commonly found in yogurt. These bacteria aid in the digestion of dietary fiber, help prevent infections, and produce essential vitamins, including folate and some B-complex vitamins. Conversely, low levels of Bifidobacteria have been linked to various health issues, such as celiac disease, obesity, diabetes, and allergies.

Although there were no statistically significant associations between long-term yogurt intake and overall colorectal cancer incidence, there was a correlation in bifidobacterium-positive tumors, according to study findings, with a 20 percent lower rate of incidence for participants who ate two or more servings of yogurt per week.

Yogurt’s bacteria may help create a healthy gut balance, strengthening the gut’s protective barrier and reducing the risk of colorectal cancer. Bifidobacteria may help lower the risk by fighting harmful bacteria and improving gut health and immunity. Bifidobacteria contribute to a healthy gut environment by producing short-chain fatty acids, which have various beneficial effects on the gut lining, inflammation, and overall gut function.

Colorectal cancer is a type of cancer that develops in the large intestine or rectum. Although colorectal cancer has historically been more common in older adults, its incidence has been rising among younger adults, with research showing an increase in diagnoses in those younger than 50 years old, making it a growing concern for this age group.

Further Research Needed

“It has long been believed that yogurt and other fermented milk products are beneficial for gastrointestinal health,” co-senior author Dr. Tomotaka Ugai, an instructor in pathology and department associate in epidemiology at Harvard University, said in the statement. “Our new findings suggest that this protective effect may be specific for Bifidobacterium-positive tumors.”

Dr. Andrew T. Chan, a gastroenterologist and chief of the Clinical and Translational Epidemiology Unit at Massachusetts General Hospital, emphasized that this study strengthens the link between diet, gut bacteria, and colorectal cancer risk. He added that it opens new avenues for research, particularly into how these factors affect colorectal cancer risk in younger populations.