Gut health has become a buzzword, but the science behind it is very real. Research shows that our gut microbiome—the community of bacteria living in our digestive tract—plays a crucial role in everything from digestion to immunity, and even brain function. 

We asked our Nouries medical adviser and co-founder Fredrik Resare to break down the science behind prebiotics and probiotics, and why both are essential for a healthy gut.

“Prebiotics are fibers found in plant-based foods that feed the good bacteria already living in your gut,” explains Fredrik. “They essentially act as fuel for the microbiome, helping it flourish and keep harmful bacteria in check.” Not all fiber is prebiotic—only the types that can be fermented by gut bacteria, such as soluble fibers found in foods like oats, leeks, and bananas.

Once these fibers reach the colon, gut microbes break them down, producing short-chain fatty acids (SCFAs). SCFAs provide energy for colon cells, support mineral absorption, reduce inflammation, improve gut barrier function, and even help regulate blood sugar and satiety.

Probiotics, on the other hand, are live microorganisms that can add to and diversify your gut flora. “Think of your gut bacteria as a community,” says Fredrik. “Probiotics help replenish and strengthen that community, making it more resilient and balanced.”

Fredrik recommends incorporating both prebiotics and probiotics daily. “Prebiotic fiber like inulin can help nourish your good bacteria,” he advises. Pair that with probiotic-rich foods like sauerkraut and kimchi, or a high-quality supplement, and you’re giving your gut the support it needs from all angles.