Can Eating Yogurt Lower Your Colorectal Cancer Risk? Experts Weigh In
Colorectal cancer cases have jumped in the last few years, with the proportion of diagnoses in people under 55 doubling from 1995 to 2019 to 20 percent. Colorectal cancer is the third most commonly diagnosed cancer and the third leading cause of cancer death in both men and women, per the American Cancer Society. This new data has obviously raised a lot of questions about why more people, and especially young adults, are developing the disease. And knowing the recent stats, it's natural to wonder how you can lower your own risk to better protect yourself.
While there are still a lot of unknowns swirling around this jump in colorectal cancer rates, a recent study suggests that there's a link between eating yogurt and a decreased incidence of certain types of this cancer.
Of course, cancer is complicated and there are so many things (like genetics and environmental factors) that can raise—and lower—your risk. But these new findings seem to offer one helpful datapoint. Here’s what an oncologist who treats colorectal cancer wants you to know about the study and what it means for everyone.
Meet the expert: Jack Jacoub, MD, oncologist and medical director of MemorialCare Cancer Institute at Orange Coast and Saddleback Medical Centers in Orange County, CA. Jeffery Nelson, MD, is a colorectal surgeon and surgical director of The Center for Inflammatory Bowel and Colorectal Diseases, part of The Melissa L. Posner Institute for Digestive Health and Liver Disease at Mercy Medical Center in Baltimore, MD.
What did the study find?
The study, which was published in the journal Gut Microbes, analyzed medical records and dietary data from more than 151,000 people who participated in two long-term studies in the US. After crunching the data, the researchers identified 3,079 people who were diagnosed with colorectal cancer. Of those, 1,121 had information available on the amount of Bifidobacterium DNA in their tumor tissue. (Bifidobacterium is a bacterial species that’s found in yogurt.)
While eating yogurt didn't lower the risk for all types of colorectal cancer, it was linked to lower odds of developing colorectal tumors that contain Bifidobacterium. Specifically, the researchers discovered that people who ate two or more servings of yogurt per week had a lower risk of developing Bifidobacterium-positive tumors. That includes Bifidobacterium-positive proximal colon cancer, which occurs on the right side of the colon and tends to have worse survival rates than people who have cancer on the left side of the colon. This "suggests that yogurt intake might lower colorectal cancer risk through the modulation of intestinal microbiota," says study co-senior author Tomotaka Ugai, MD, PhD, a pathology researcher at Mass General Brigham and an epidemiology associate at the Harvard T.H. Chan School of Public Health.
In other words, consuming yogurt could have an "antitumor" or "tumor-suppressing effect" on this specific type of colorectal cancer, the researchers concluded.
How does yogurt lower colorectal cancer risk?
This particular study didn’t specifically look at how yogurt may lower the risk of certain types of colorectal cancer—it just found a link between consumption and lower incidence in the population they studied. It’s also important to point out that the researchers didn’t find that having a yogurt habit lowered the risk of developing all types of colorectal cancer, just certain types.
Still, the findings are "very interesting" and is likely a result of the yogurt's impact on the gut's microbiome, says Jack Jacoub, MD, oncologist and medical director of MemorialCare Cancer Institute at Orange Coast and Saddleback Medical Centers in Orange County, CA.
Other experts agree. "There really isn’t any question that the gut microbiome can play an important role in colorectal cancer pathogenesis, but the exact mechanisms remain unclear," says Jeffery Nelson, MD, colorectal surgeon, and surgical director of The Center for Inflammatory Bowel and Colorectal Diseases, part of The Melissa L. Posner Institute for Digestive Health and Liver Disease at Mercy Medical Center in Baltimore, MD.
Still, exposing your body to things like the healthy bacteria in yogurt could potentially lower your risk of certain types of cancer, Dr. Jacoub says. “There is a sense that maybe you can change your diet and alter some cancers that develop in the gastrointestinal tract, because that’s something you have control over,” he says. “Yogurt can change the flora of the gastrointestinal tract, and potentially reduce the presence of a bacteria that can be in cancer.”
How much does long term yogurt consumption decrease risk?
According to this study, eating at least two servings of yogurt a week lowers the risk of developing Bifidobacterium-positive colorectal tumors by 20 percent.
What counts as “long term” intake?
The researchers looked at participants’ yogurt intake since 1976 and 1986, depending on which long-term study they analyzed. So, it’s safe to say that many years of eating yogurt should help.
How much yogurt would I need to eat to see the benefits?
The researchers found that having at least two servings of yogurt a week was helpful. A serving of yogurt is 6 ounces, so having at least 12 ounces of yogurt on a weekly basis may help lower your colorectal cancer risk.
Also of note: "Plain yogurt is better than sweetened yogurt," says Dr. Ugai.
Of course, if you’re considered high risk for developing colorectal cancer, it’s crucial to check in with a doctor to learn more about screening and personalized ways of lowering your risk. Dr. Jacoub also stresses that colorectal cancer tends to develop due to a mix of genetics, your environment, and your diet, making it tough to say that eating yogurt alone will keep you from getting the disease.
But Dr. Jacoub also says these findings are worth considering. “Having a couple of cartons of yogurt a week is safe. Even if the data is in its infancy, it makes a lot of sense,” he says. “This is a good return on investment.”
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