By now, most of us have heard of the term “probiotics” — those foods like yogurt and tempeh that contain live microbes: “friendly” bacteria that aid in digestion. However, prebiotics are a less familiar topic — but similarly important in keeping our immune systems healthy.

Prebiotics are natural, indigestible plant fibers that actually feed the probiotic microbes in the intestinal tract. After all, bacteria need to eat too. And what prebiotic delicacies do they like to dine on? Fermentable, fibrous carbohydrates found in foods like garlic, artichokes, soybeans and onions. Our bodies can’t actually digest fiber, but probioticsdo — so feeding them keeps these helpful bacteria alive and well. Replenishing and diversifying the bacteria populations in our stomach is crucial for digesting food and absorbing nutrients.

Researchers in the fields of immunology, infectious disease and basic science are studying the health benefits associated with feeding and stimulating the growth of these helpful bacteria, but the positive effects may be numerous. Prebiotics have been linked to improving insulin levels, enhancing immunity and reducing symptoms of respiratory infections.

Scientists in China are also looking at the role probiotics and prebiotics play in obesity. Although more research is necessary, it’s possible that using certain prebiotics to promote certain types of probiotics while reducing others in our digestive system may help people lose weight better than cutting calories alone.

For now, however, a balance of prebiotics and probiotics are the best way to maintain digestive health. So the next time you’re at the grocery store, grab some probiotic-rich foods to feed those friendly bacteria. Whole grains, legumes, asparagus and bananas are all good choices.