If you're having digestive issues such as bloating [1], you're taking antibiotics, or you want to prevent yeast infections, doctors often recommend taking or eating probiotics [2]. They contain the same bacteria found in the digestive tract, and when stress, diet, or medications throw your system out of whack, consuming probiotics can help restore the balance. OK so we know all about probiotics, but have you been hearing about prebiotics? What's the difference, and should you take them, too?

What are Prebiotics?

Registered dietitian Leslie Langevin, MS, author of The Anti-Inflammatory Kitchen Cookbook [3], explained that prebiotics are the "food" for the good bacteria that exist naturally in your gut.

Prebiotics are found in a variety of starches and fibres including beans, whole grains, onions, asparagus, apples, green veggies, and artichokes. When you eat these foods, they ferment in your large intestine by the bacteria that live there, which produces the food and the environment that the bacteria need to thrive. In supplements or store-bought foods like bars, they often add inulin, which is a prebiotic fibre.

What's the Difference Between Probiotics and Prebiotics?

Our gut is filled with bacteria; some good and some bad, and probiotics are "good" live active bacteria that help our gut stay healthy and balanced. They can be found in fermented food such as sauerkraut, tempeh, kimchi, pickles, or kombucha, or in supplements.

As mentioned above, prebiotics are the food for the probiotics. "Most often you will have a mix in fermented foods and supplements that include: lactobacillus, bifidobacterium, and saccharomyces, which is a beneficial yeast," Langevin said.

Probiotics and prebiotics work together to improve your gut health. "Try to imagine that your gut is a garden," explained Niket Sonpal, MD, a board-certified gastroenterologist in New York City and an adjunct assistant professor at Touro College of Medicine, in a previous interview [4]. "Probiotic bacteria are the seeds in the garden, [while] the prebiotic fibre is the water and fertilizer that helps the seeds to grow and flourish."

Do I Need to Take Prebiotics?

Prebiotics are readily available in healthy high-fibre foods, so Langevin said if you eat a good amount of these, you don't need to take supplements or go out of your way to eat foods that contain prebiotics [5]. If you aim to get enough fibre (the USDA recommends 25 grams a day [6] for women under 50 years old), then you're getting enough. Eating enough fibre can also help prevent constipation, which can prevent bloating.

On a related note, Langevin added that to keep your gut bacteria healthy, "limit sugar [7]. A high-sugar diet and a diet high in processed foods can actually kill off some of your beneficial bacteria."