Weekly Yogurt Consumption Linked to Reduced Colon Cancer Risk

A new study suggests that regularly eating yogurt might reduce the risk of a specific type of colon cancer.

The research, published in the journal Gut Microbes, found that people who routinely consumed two or more servings of yogurt per week had lower rates of proximal colorectal cancer containing a bacterium called Bifidobacterium.

“Yogurt is a source of probiotics that can directly influence the gut microbiome,” Peyton Berookim, MD, of Cedars-Sinai Medical Center Division of Gastroenterology, who was not involved with the study, told Health. “Regular consumption of yogurt could increase the population of beneficial bacteria” in the gut.

Proximal colorectal cancer occurs on the right side of the colon. It is more deadly than distal colon cancer, which originates on the left side. 

The type positive for Bifidobacterium is quite common, accounting for about one-third of colorectal cancers, study author Shuji Ogino, MD, PhD, a professor in the Department of Epidemiology at Harvard’s T.H. Chan School of Public Health, told Health.

Though the bacteria in yogurt has long been identified as beneficial for health, the researchers said previous studies have questioned their impact on colon cancer. Their research aimed to clarify this dietary link by assessing long-term data collected from a vast pool of participants.

The scientists began with information from two long-running studies: the Nurses’ Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). Since the 1970s and 1980s, these studies have tracked the dietary habits of over 150,000 people, including their intake of sugar, alcohol, fiber, and total calories, as well as their consumption of yogurt generally (not details like various fat percentages, added sugar levels, or flavorings).

As part of the research, scientists gathered tissue samples to identify participants who developed colorectal cancer. Ultimately, the new study’s authors used data from over 132,000 participants.

By analyzing this large body of information, the researchers found that, among people who developed colorectal cancer, 31% of cases were Bifidobacterium-positive, while 69% were Bifidobacterium-negative.

They then used multivariable-adjusted hazard ratios (a statistical measure of evaluating risk) to analyze a possible link between eating yogurt and these cancers. While regular yogurt consumption of two servings per week or more wasn’t associated with lower colorectal cancer risk in general, it was linked with a 20% lower risk of the Bifidobacterium-positive type.

While the study shows promise, the science on the connection between yogurt consumption and colorectal cancer risk is far from settled. The research in the early stages, and the current study has some notable limitations.

For one, it’s hard to say whether the study identified causation or merely association, study author Satoko Ugai, PhD, a postdoctoral research fellow at the Harvard T.H. Chan School of Public Health, told Health.

The study also relied on self-reported dietary habits, increasing the likelihood of errors.

And the NHS and HPFS studies that provided data for the researchers only followed health professionals, the majority of which were white, making it questionable whether the new study’s findings would apply to the general population.

Still, a growing body of research indicates that the live and active cultures in yogurt and other fermented foods, many of which contain probiotics, can positively influence the gut. 

“Consuming yogurt regularly may contribute to a balanced gut microbiome,” Berookim said. “Having a balanced microbiome could potentially reduce inflammation or dysbiosis, which is known to play a role in the development of colon cancer.”

“This could be a positive reason to include probiotic-rich foods like yogurt in your diet as part of an overall healthy lifestyle,” Berookim added.

Just remember that yogurt consumption—and diet generally—is just one possible factor in colon cancer prevention. Genetics, exercise, alcohol consumption, weight, environment, and other influences may impact risk. 

If you do decide to bump up your yogurt consumption, though, experts agree on one thing: It’s best to stick to varieties with minimal added sugar. 

“Many flavored yogurts contain added sugars, which can offset the health benefits of the probiotics and other nutrients,” Berookim said. “Excess sugar can contribute to weight gain, increased inflammation, and a higher risk of metabolic conditions, all of which are linked to an increased risk of certain cancers, including colon cancer.”