Simple, widely available foods like yogurt may play a meaningful role in colorectal cancer prevention, according to a large new analysis of U.S. federal health survey data that adds to growing scientific interest in the gut microbiome’s role in cancer risk.
Researchers examined data from the National Health and Nutrition Examination Survey, or NHANES, covering nearly two decades from 2001 to 2020, focusing on 9,405 American adults aged 50 and older. Using dietary questionnaires and supplement-use surveys, they compared self-reported colorectal cancer history against participants’ consumption of yogurt, probiotics, and prebiotics — the fibers and other compounds that feed beneficial gut bacteria.
After adjusting for factors including age, sex, race, income, education, smoking status, and red meat intake, the researchers found that any consumption of yogurt, probiotics, or prebiotics was associated with roughly 50 percent lower odds of self-reported colorectal cancer, compared with no consumption at all.
The findings, published in the journal Nutrition & Diabetes, build on a growing body of related research. A separate long-term study from Mass General Brigham, tracking participants for decades, previously found that eating two or more servings of yogurt per week was linked to lower rates of colorectal tumors — an effect that appeared strongest in tumors containing high levels of Bifidobacterium, a beneficial bacterial strain commonly found in yogurt. That research found detectable Bifidobacterium in the tumor tissue of roughly 30 percent of colorectal cancer patients studied, hinting at a possible biological mechanism: yogurt’s live bacterial cultures may help suppress tumor growth through immune and cell-signaling pathways.
Researchers caution that the new NHANES analysis is observational and cross-sectional, meaning it captured a single snapshot in time rather than tracking individuals over years, and cannot prove that eating yogurt or taking probiotics directly prevents cancer. The study also relied on self-reported cancer diagnoses and food intake, and did not capture the dose, duration, or specific bacterial strains involved. Still, the authors say the consistency of the association across a large, nationally representative sample supports further investigation into diet- and microbiome-based strategies for reducing colorectal cancer risk — one of the leading causes of cancer death in the United States.
