Maybe you’ve heard of probiotics, those strains of good bacteria that live in your gut and may help your health? Well, prebiotics may also be a key to everything from maintaining a healthy weight to toughening up your immune system. Here’s what the science says.
What Are Prebiotics and How Do They Work?
Dietitians and health experts use the term “microflora” to summarize the vast, complex, and important world of bacteria living in your digestive system. “Flora” is an interesting way to put it, because in many ways the mix of good and bad bacteria in your gut is like a garden. If good bacteria, also known as “probiotics,” are the most beneficial plants in your garden, then “prebiotics” are plant food. Prebiotics help probiotics flourish by way of fiber, inulin (a form of soluble fiber), and resistant starches.
And like a garden, the more well-fed your microflora is, the more likely you are to reap the benefits associated with probiotics: a healthier immune system, a less worrisome digestive system, and less of a chance you have to go on Nutrisystem.
The good news is that you can find prebiotics in a host of common foods that also happen to be super healthful for you anyway.
The 8 Best Prebiotic Foods and Their Benefits
Leeks, Onions, and Garlic
These foods, all considered “alliums,” are good sources of the soluble fiber inulin. Consuming inulin as part of a high-fiber diet may help prevent colon cancer, lower the risk of cardiac disease, and may encourage a healthy weight, according to a 2013 study published in the journal Nutrients (1). Fair warning: Eat these foods to increase your inulin levels after your next big work meeting or date.
Unprocessed grains are full of the non-digestive fibers that good gut bacteria love. But note the world “unprocessed.” Sugary breakfast cereals, white bread, and pasta made from refined flour don’t count. Though more research is needed to determine how whole grains work as a prebiotic, a 2015 study published in Healthcare found that barley, rye, wheat, corn, rice, and oats were all contributed to feelings of fullness, otherwise known as “satiety” (2).
Everyone’s favorite yellow fruit (okay, fine, there aren’t that many) is a good source of fiber, but also fructooligosaccharide—a really long word for a beneficial form of natural sugar. Back in 2009, Spanish researchers determined that people who ate diets high in that really long word had less constipation than those who didn’t (3).
What you see bundled in the grocery store are actually the stalks of a small shrub. They’re high in the prebiotic inulin, but they’re also a rich source of disease-fighting antioxidants, according to a 2010 study by Indian scientists (4).
Sick of eating asparagus steamed? Take a sharp peeler to the stalks and cut thin ribbons into a bowl. Mix with fresh lemon juice, salt, pepper, and a little Parmesan for a fresh-tasting raw salad.
This spiky vegetable has a fibrous heart that’s also high in prebiotic inulin. Beneficial changes in gut bacteria may also improve sleep, according to a 2017 study published in the journal Frontiers in Behavioral Neuroscience (5). The research, which was conducted on rats, found that rodents who ate a diet high in prebiotics may lower stress levels associated with poor sleep. More studies are required to prove an effect in humans.
You know these pods of deliciousness as a pop-and-eat appetizer at Japanese restaurants. Well, edamame is actually a soybean and soybeans themselves are a high-fiber food that’s been classified as a prebiotic. Find a bag in the freezer aisle, steam the beans at home, and sprinkle with sea salt. Or try them shelled in your next stir-fry.
When Should You Take Prebiotic Supplements?
“Before diving into the prebiotic supplement game, look at your own diet and foods that provide naturally occurring prebiotics, like inulin, pectin and fiber, for example,” says Chris Mohr, a registered dietitian and co-owner of Mohr Results. “The fiber and other nutrients within these foods offer the ‘plant food’ that your flora needs to thrive,” Mohr says.
Still interested in a supplement? Talk to a dietitian before proceeding.