Locations:
Search IconSearch

What Are Prebiotics and What Do They Do?

Here’s why prebiotics matter

Carrots, bell peppers, onions, shallots, tomatoes and bananas are piled on a table.

The bacteria in your gastrointestinal tract (what doctors call your gut microbiota) never let any of your food go to waste. Those helpful microorganisms break down and digest your food in order to enhance your immune system and help with inflammation. But what’s keeping those helpful little bugs alive? And how can you get that bacteria to work better for you? The answer is prebiotics.

Advertisement

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

Digestive disease researcher and registered dietitian Gail Cresci, PhD, RD, shares some secrets behind prebiotics, how they differ from probiotics and a list of foods you can eat to keep your gut bacteria healthy and strong.

What do prebiotics do?

To understand prebiotics, you have to know what probiotics are, as they’re often confused with each other.

Probiotics are live microorganisms that’ve been isolated from human intestines and are shown to have beneficial effects when they’re consumed in adequate amounts. Probiotics can be found in dietary supplements and fermented foods like kombucha, yogurt or tempeh. In order to be considered a probiotic, after ingestion, the microorganisms need to survive stomach acid and bile so they can make it all the way to your colon to meet up with the other live microorganisms living there. Once they arrive, they need to be able to survive in that environment. The more variety of these healthy microorganisms you have, the more they can do for you.

Prebiotics function as a food source for your gut’s microorganisms — and they need to bypass digestion and make it all the way to your colon. There, the microorganisms metabolize and ferment the prebiotics to survive. This metabolism and fermentation process is beneficial to your gut health because it creates a variety of other byproducts that help you in a number of ways.

Advertisement

When prebiotics are broken down by the microorganisms in your gut, different short-chain fatty acids are created depending on the kind of prebiotic. As a result, these short-chain fatty acids do a number of things like provide energy to your colon cells, help with mucus production and aid in inflammation and immunity.

“Different microorganisms may use different prebiotics, so not every prebiotic gives you the same effect,” says Dr. Cresci.

Benefits of prebiotics

The benefits of prebiotics are wide-ranging. There’s still a lot of research being done to determine exactly how food sources for your gut microbiota work, but here are a few things we know prebiotics do:

  • Help regulate bowel movements.
  • Produce neurotransmitters that go back and forth between your gut and your brain to trigger mood changes and other processes.
  • Stimulate your body to make hormones that aid in appetite, appetite suppression and more.
  • Help your bones mineralize and absorb calcium and phosphorus, which can improve bone density.
  • Improve how well your immune system functions.
  • Enhance your body’s anti-inflammatory response.
  • Increase production of good bacteria and decrease bad bacteria that causes disease.

“The number of benefits prebiotics may have is complex,” says Dr. Cresci. “So much is always continually being discovered.”

Prebiotic foods

Prebiotic foods are usually high in certain types of fiber known as fermentable soluble fiber. How you cook your food determines how many prebiotics are available, too, because your food changes composition based on how you cook it (or not cook it). Although there are many kinds of prebiotics, three of the most common are found in resistant starches, inulin and pectin.

Resistant starches

Like fiber, resistant starches resist digestion and end up as a main food source for microorganisms in your colon. When resistant starches are broken down, they often produce butyrate, which helps with water and electrolyte absorption, immune system functionality and anti-inflammation.

“If you’re eating foods that help produce butyrate, and you have the right bacteria in your gut, then your butyrate levels will be higher, which has been shown to have all these beneficial effects,” says Dr. Cresci.

Take potatoes, for example. There’s less resistant starch when you bake potatoes, but if you boil them and let them chill, that white, starchy film that results is the resistant starch you want. Resistant starches can be found in:

  • Boiled and chilled potatoes.
  • Green bananas.
  • Barley.
  • Oats.
  • Rice.
  • Beans.
  • Legumes.

Inulin

Inulin is a prebiotic fiber contained in many plants. This prebiotic can help you feel full for longer periods, assisting with overeating and helping with bowel movements. It can also help lower LDL cholesterol (bad cholesterol), stabilize blood sugars and increase and maintain the good bacteria in your gut. It may also help reduce your risk of colon cancer. While you can take inulin as a supplement in gummy, tablets, capsules and powder form, foods high in inulin tend to also have additional benefits by providing antioxidants and other vitamins. Some of those foods include:

Advertisement

  • Asparagus.
  • Burdock root.
  • Chicory root.
  • Dandelion greens.
  • Garlic.
  • Jerusalem artichokes.
  • Leeks.
  • Onions.
  • Soybeans.
  • Wild yams.

Pectin

You’ll find pectin in a lot of fruits, especially in the pulp of raw apples. Pectin is a type of gel-like starch, often used to create jams and jelly. This starch has antioxidant and anti-tumor properties. It also may enhance the skin cells of your intestinal lining, decrease the ability for bacterial diseases to take root and improve the diversity of microorganisms in your gut. More human studies are needed to determine other beneficial results. Foods high in pectin include:

  • Apples.
  • Apricots.
  • Carrots.
  • Green beans.
  • Peaches.
  • Raspberries.
  • Tomatoes.
  • Potatoes.

When to take prebiotics (and when you shouldn’t)

So, where and how should you start using prebiotics? Dr. Cresci suggests working them into your diet slowly.

“Don’t go overnight and start eating a ton of these,” she advises. “When they start working and waking up your microbiota, it’ll start creating more gas, so you don’t want a reverse effect where you feel super bloated or gassy. This should be a gradual introduction into your diet.”

And because your body operates on a circadian rhythm, the microorganisms in your gut are more active during the day, so you’ll want to make sure you don’t eat prebiotics too late in the evening.

Advertisement

If you have digestive issues like irritable bowel syndrome (IBS), you may have trouble digesting certain prebiotics, especially stone fruits like peaches, mangos and cherries.

But for the most part, while there’s a lot left to be studied in the field of prebiotics, Dr. Cresci says they can’t hurt if you incorporate them into your diet through natural sources.

“There’s really no way to go wrong with eating fruits and vegetables,” says Dr. Cresci. “You’re going to get fiber, vitamins and minerals, and most likely, you’re also going to get some prebiotic.”

Advertisement

Learn more about our editorial process.

Related Articles

A server carries a platter full of nutritious foods
December 20, 2024/Nutrition
How Much Cholesterol Per Day Is Healthy?

There’s no limit on the amount you should have each day, but experts are focused on saturated fat

Half an avocado with the pit inside sits next to a glass pitcher of avocado oil and a spoon with some oil on it
December 19, 2024/Nutrition
Yes, Avocado Oil Is Good for You

This healthy oil is packed with nutrients and great for roasting, drizzling and even baking

Smiling person holding martini glass, with another person's hand also holding maritini glass
December 17, 2024/Digestive
Can Alcohol Cause Diarrhea?

Yes, diarrhea is common after drinking too much alcohol — and the best treatment is to hydrate and wait it out

Person wearing oven mitts removing a baking sheet of vegetables from the oven
December 13, 2024/Eye Care
Look At This! 40+ Foods To Boost Your Eye Health

A diet built around fruits, vegetables and healthy fats is a clear 20/20 benefit for your vision

Healthcare provider discussing stomach cancer with patient, with oversized gastric cancer ribbon in background
December 12, 2024/Cancer Care & Prevention
Life With Advanced Stomach Cancer: What Changes

Your relationships with food, physical fitness, social interactions and advance planning desires may need to be modified

Sliced grilled chicken sprinkled with sesame seeds over mixed greens with tomatoes and onions
December 12, 2024/Digestive
How To Change Your Diet After Gallbladder Removal

After a cholecystectomy, your body may temporarily have a hard time processing fat and fiber

Person with earbud in standing at kitchen sink drinking a glass of water
December 11, 2024/Nutrition
How To Get Caffeine Out of Your System

There’s no proven way to remove the natural stimulant from your body, but you can counter its effects by staying hydrated and getting in some movement

Bowl of oatmeal, topped with fried egg and avocado, with small bowl of seeds on table
December 10, 2024/Cancer Care & Prevention
Foods To Eat and Avoid When You Have Advanced Gastric Cancer

Opt for soft foods or liquids that are rich in protein, calories and vitamins

Trending Topics

Person sitting on floor at night next to bed in deep thought, with partner sleeping in bed
Understanding Mental Load: What It Is and How It Affects You

When you get bogged down with mental tasks, you can experience mood changes, sleeplessness and more

Hands holding two different kinds of pain medications separated by a white line
Can You Take Acetaminophen and Ibuprofen Together?

You can alternate these OTCs to help with pain management and fever reduction

Smiling person with headphones on, sweeping floor in living room
Understanding Non-Exercise Activity Thermogenesis (NEAT Exercise)

Non-exercise activity thermogenesis is all the activity we do that’s not technically exercise but is still important to your health and well-being

Ad