Your Guide to Prebiotics

Medically Reviewed By Jerlyn Jones, MS MPA RDN LD CLT
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Prebiotics are a form of dietary fiber that help healthy bacteria flourish in your gut. These bacteria produce nutrients, leading to a healthier digestive system. The bacteria in your gut are known as “gut microbiota.” They have many uses, such as breaking food down in your gut and helping with inflammation.

This article explains what prebiotics are, the different types, and where they come from. It also explains how they work in the body, the benefits, and which foods to eat for maximum digestive health.

What are prebiotics?

hand holding peaches
Tatjana Zlatkovic/Stocksy United

Prebiotics are dietary fibers that support digestive health. The bacteria in your gut, known as “gut microbiota,” eat or “ferment” the food you eat. Prebiotics help these bacteria do their job.

Prebiotics vs. probiotics

Prebiotics and probiotics play different roles in your digestive health. Whereas prebiotics help the friendly bacteria in your gut, probiotics are live bacteria that you can find in certain foods and supplements. Prebiotics are plant fibers that act as fertilizers for bacteria.

The table below illustrates the differences between prebiotics and probiotics.

are fiber that bacteria feed onare healthy bacteria that live in your gut
are for healthy probiotics in the gutfeed off of prebiotics
are not affected by temperature or aciditycan die from certain temperatures or acidity in the gut
are present in fruits and vegetables, such as bananasare present in fermented foods, such as soy or kimchi

Read more about probiotics here.

What are synbiotics?

Synbiotics are a combination of prebiotics and probiotics. They can take the form of food ingredients or dietary supplements to support your gut bacteria.

How do prebiotics work in the body?

Prebiotics work by stimulating the growth or activity of healthy bacteria in the colon. They essentially function as a food source for probiotics, which are live bacteria or microorganisms. These live bacteria ferment the prebiotics, creating a variety of byproducts that are beneficial to your body.

During this process, short chain fatty acids are created. This results in a number of benefits, such as helping inflammation in the body or giving energy to cells in the colon.

Prebiotics are able to modify the environment of the gut by changing the pH, or acidity.

How do prebiotics benefit health?

There are a number of ways in which prebiotics are beneficial to human health.

For something to be prebiotic, it needs to have specific qualities, such as:

  • a resistance to the acidity of the stomach
  • an inability to absorb into the gastrointestinal tract
  • an ability to ferment

Prebiotics usually have a number of health benefits, including:

  • increasing the good bacteria in the gut, known as Bifidobacteria and Lactobacilli
  • decreasing the number of bad bacteria in the gut
  • decreasing the risk of developing allergies
  • improving the immune system
  • helping regulate bowel movements
  • helping the body produce hormones that help with appetite suppression
  • absorbing calcium in the bones, thereby improving bone density
  • enhancing the anti-inflammatory response in your body

Why are bacteria beneficial in the body?

Bacteria in the gut are beneficial for a number of reasons, such as:

  • protecting you from harmful bacteria in the gut
  • helping the immune system function correctly
  • reducing inflammation

Types of beneficial bacteria include Bifidobacteria and Akkermansia.

What types of prebiotics are there?

There are many types of prebiotics, and most of them are carbohydrates. Types of prebiotics include:

  • fructans, which are present in onions and leeks
  • galactooligosaccharides, which are present in beans and root vegetables
  • starch- and glucose-derived oligosaccharides
  • non-carbohydrate oligosaccharides

Which foods are prebiotics?

Prebiotics naturally exist in many foods. These foods include:

  • asparagus
  • garlic
  • onion
  • chicory
  • artichoke
  • wheat
  • honey
  • beans
  • cow and human milk
  • peas
  • rye
  • soybean

Prebiotic foods break down into different groups. The sections below outline these in more detail.

Resistant starches

These are foods that resist digestion and end up as a food source for the good bacteria in your gut. When they do break down, they produce a compound called butyrate, which is a type of fatty acid.

Butyrate helps with a number of bodily functions, such as:

  • water and electrolyte absorption
  • anti-inflammation in the body
  • immune system function

Resistant starches are present in foods such as:

  • potatoes
  • oats
  • rice
  • beans
  • green bananas


Inulin is a prebiotic fiber present in many plants. It has a number of benefits, including:

  • helping with bowel movements
  • lowering cholesterol
  • stabilizing blood sugars
  • making you feel fuller for longer after eating

Foods containing inulin include:

  • asparagus
  • leeks
  • garlic
  • onions
  • wild yams


Pectin is a type of starch that people often use in jams and jellies. It is present in many fruits. Pectin enhances the skin cells in the intestinal lining and decreases the ability of diseases to take root in the gut.

Foods containing pectin include:

  • apples
  • peaches
  • raspberries
  • tomatoes
  • carrots

What conditions can prebiotics help?

There are a number of studies in which prebiotics have helped with certain conditions. Including prebiotics in your diet can boost the good bacteria in your gut, leading to a host of benefits for the body.

Conditions that studies have shown prebiotics to improve include:

Prebiotics have also been found to lower the risk of cardiovascular diseases by reducing inflammation in the body.

What is the correct way to include prebiotics in your diet?

There are few side effects associated with including prebiotics in your diet. However, it is important to slowly introduce prebiotic foods so as not to experience bloating or excessive gas.

Because prebiotics act as fertilizers for the microbiota in your gut, eating lots of prebiotic foods at once may induce gas.


The most beneficial effects of including prebiotics in your diet include helping with inflammation in the body, enhancing your gut bacteria, and contributing to good overall digestive health. Prebiotics can “feed” the probiotics in your gut, stimulating growth activity.

Foods that contain prebiotics include potatoes, leeks, peaches, and other starchy carbohydrates. Be sure to include prebiotics, or fruits and vegetables in general, in your diet for a whole host of benefits.

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Medical Reviewer: Jerlyn Jones, MS MPA RDN LD CLT
Last Review Date: 2022 Jul 25
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