Can Dairy Foods Be Both Good And Bad For Gut Health? Here’s What A New Study Shows

Dairy has long occupied a confusing space in nutrition conversations. One day it’s praised for calcium and protein; the next, it’s blamed for bloating, inflammation, or “ruining” gut health. A new study

adds much-needed nuance to this debate, showing that dairy’s impact on the gut microbiome depends largely on what kind of dairy you’re consuming—and how your body responds to it.

Why Gut Bacteria Matter More Than You Think

Your gut microbiome is a vast ecosystem of trillions of bacteria that influence digestion, immunity, metabolism, and even mood. Greater microbial diversity is often associated with better overall gut health, while imbalances have been linked to inflammation and chronic disease. This is why scientists are increasingly interested in how everyday foods—like milk and cheese, shape these bacterial communities.

Milk: A Boost for Microbial Diversity

According to the study, higher milk consumption was associated with increased gut bacterial diversity, a generally positive sign. Milk drinkers also showed higher levels of bacteria linked to anti-inflammatory effects and better metabolic health. One possible reason is lactose. While often viewed negatively, lactose can act as a prebiotic, feeding beneficial bacteria that thrive in the gut. For people who digest lactose well, milk may quietly support a healthier microbial environment.

Cheese: A More Complicated Story

Cheese, however, told a different tale. Higher cheese intake was linked to reduced levels of certain gut bacteria involved in producing short-chain fatty acids, compounds that help maintain the gut lining and regulate inflammation. This doesn’t mean cheese is “bad,” but it highlights that its effects are more complex. Most cheeses are low in lactose due to fermentation, which changes how gut microbes interact with them.

Not All Dairy—or Guts—Are the Same

Importantly, the study doesn’t suggest eliminating cheese or loading up on milk indiscriminately. Individual tolerance matters. People with lactose intolerance, dairy sensitivities, or specific gut conditions may experience very different effects. Fermented dairy products like yogurt and kefir often show separate benefits because of their live cultures, which weren’t the central focus of this research.

The Bigger Picture: Balance Over Binaries

The key takeaway is that dairy isn’t universally good or bad for gut health. Its effects depend on the type of dairy, your existing gut microbiome, and the rest of your diet. When paired with fiber-rich foods, plant diversity, and overall dietary balance, dairy can play a supportive—but not standalone—role in gut health.