The dairy science behind a healthier gut … and beyond

Fermented dairy foods are having a moment, not because they’re trendy, but because the science behind them keeps getting stronger.

Scientists and health-conscious consumers are increasingly focused on the gut as more than a place where food gets digested. It can be a key player in everything from immunity to mental health. A growing body of evidence continues to confirm what many in the dairy science field have long observed: fermented dairy foods do more than nourish. They actively support digestive and systemic health.

A new narrative review in Nutrition Reviews, funded by the National Dairy Council (NDC), adds important depth to that understanding. The review examined 37 studies exploring the effects of yogurt, kefir, fermented milk and cheese on gastrointestinal symptoms and biomarkers of gut health.

Across studies involving healthy children and adults, as well as individuals with chronic conditions, fermented dairy foods were consistently linked with beneficial health effects. The findings pointed to improved digestive comfort, favorable shifts in the gut microbiota and measurable reductions in inflammation. Specifically, the review found measurable improvements in gut barrier integrity and reductions in tumor necrosis factor-alpha (TNFα), a key biomarker tied to inflammation. This suggests fermented dairy foods may help calm the body’s inflammatory response, supporting immune and metabolic health in ways that reach beyond digestion.

Just as important, none of the studies reported any harmful effects. Of the 37 studies, 27 showed significant improvements in one or more measures of gut health, while the remaining 10 reported neutral outcomes. That consistency builds confidence that fermented dairy can play a meaningful role in supporting digestive wellness and immune function across diverse populations. Plus, fermented dairy foods provide key essential nutrients like calcium, B vitamins, zinc, selenium and protein, offering additional benefits.

When viewed alongside existing research linking yogurt and kefir to improved lactose tolerance, better metabolic outcomes and reduced risk of chronic disease, the case for fermented dairy becomes even stronger. This research reinforces NDC’s long-standing mission to advance credible science around dairy’s role in health. For more than a century, our farmer-founded organization has led and supported research that helps define dairy’s nutritional value and health benefits while informing innovation across the food system.

As global interest in the gut-microbiome connection continues to grow, fermented dairy stands out as a proven, practical way to support well-being. The science continues to reveal that fermentation doesn’t just transform milk, it helps unlock its full potential. DF

Chris Cifelli, Ph.D., is senior vice president of Nutrition Research at the National Dairy Council.