Do prebiotics work? Find out with this guide.

Prebiotic vs. Probiotic: Benefits and Differences

Last modified on June 26th, 2023

Prebiotic foods and prebiotic supplements can be essential for gut health. They can have other benefits, but you aren’t alone if you find it confusing to know the differences between prebiotics and probiotics and their benefits.

What Are Prebiotics?

The bacteria in your gut microbiota, which is your gastrointestinal tract, help break down food and digest it. They can help improve your immune system and tamp down on inflammation, and Prebiotics can help your good bacteria function the way they should.

To understand how a prebiotic works and how it’s good for you, you have to understand how they compare to probiotics.

Probiotics are live microorganisms. Probiotics are isolated from the intestines and have beneficial effects when we consume adequate amounts. Probiotics are found in foods like kombucha, tempeh, yogurt, and other fermented foods.

To be considered a probiotic, it has to survive bile and stomach acid after it’s ingested to reach your colon. Once the probiotic reaches your colon, it comingles with all the other microorganisms populating it. The probiotic has to be able to survive in the environment of the gut to create health benefits.

Prebiotics, by contrast, are a food source for your gut’s bacteria. Prebiotics also have to bypass digestion and reach your colon. Once a prebiotic reaches your colon, the good bacteria or microorganisms there will metabolize and ferment the prebiotics, using them for survival. The metabolism and fermentation benefit your gut health by creating other byproducts.

Short-chain fatty acids are created when the gut microorganisms break down prebiotics, and different ones are created depending on the prebiotic.

Short-chain fatty acids can provide energy to the cells of your colon, help with immune health and inflammation, and aid with mucus production.

Different microorganisms can use different prebiotics, so this means that different prebiotics are going to give you different effects and benefits.

To put it in even simpler terms, prebiotics are food for probiotics.

Prebiotics come primarily from carbs and fiber you can’t digest, and your beneficial gut bacteria eat the fiber. Your gut bacteria are collectively referred to as your gut microbiota or flora. When you have a balanced consumption of both prebiotics and probiotics, it helps optimize the health of your gut microbiota.

Types of prebiotics include:

  • Fructans
  • Pectic oligosaccharides
  • Non-carbohydrate oligosaccharides
  • Starch and glucose-derived oligosaccharides

You’ll sometimes hear prebiotics referred to as microbiome fertilizers.

The Importance of Beneficial Gut Bacteria

When you have good bacteria populating your digestive tract, it can protect you from harmful organisms. A diverse set of good bacteria can help reduce the risk of obesity, improve depression symptoms, help your immune system function well, and help with many other benefits.

Some of your gut bacteria also form short-chain fatty acids and vitamin K.

Short-chain fatty acids are the primary source of nutrients for your colon cells. They help strengthen your gut barrier so toxins and harmful substances, often the effect of what’s known as a leaky gut, can’t enter your bloodstream. When you have a strong gut barrier, it also reduces inflammation and may lower your risk of developing cancer.

The food you eat plays a significant role in the health and diversity of your gut microbiota.

If you have a diet high in unhealthy fats and sugar, it can negatively influence the population of your gut bacteria.

Less healthy gut flora and higher concentrations of harmful bacteria are associated with a higher body mass index.

Antibiotics can permanently change certain bacteria present in your gut, especially if you took them a lot when you were a child or teen. Because of how pervasive antibiotic use is, researchers are looking at how this could negatively impact health later.

What Are Prebiotics Good For?

Are prebiotics good for you? They can be—they can be very beneficial.

So what do prebiotics do for the body?

Prebiotics are necessary for healthy gut microbiota. Your gut microbiota influences your risk of developing various diseases, including colon cancer, type 2 diabetes, and inflammatory bowel disease. Prebiotics carry out functions related to regulating your immune system and nutrient metabolism.

Bacteria in your large intestine ferment prebiotics, which release short-chain fatty acids. Prebiotics can promote the growth of beneficial bacteria. For a compound to be called a prebiotic, it has to resist digestive enzymes and stomach acid and shouldn’t be absorbed in the GI tract. It should be able to be fermented by the microbes in your intestines, and it should stimulate the activity and growth of your intestinal bacteria in a way that improves your health.

One thing that prebiotics are good for, as we’ve mentioned, is the production of short-chain fatty acids, including butyrate. These are integral to gut and metabolic health.

Specific benefits of prebiotics include the following.

Help with Some Gut Conditions

When discussing why prebiotics are good for you, the biggest benefit you can see fairly soon after including more of them in your diet or taking a supplement is that your gut health is likely to improve.

In a 2020 review, treatment with inulin, which is prebiotic, helped people who had IBS with constipation. Prebiotics may improve the time it takes for food to move through the digestive tract and the frequency and consistency of stool.

Metabolic Health

A diet high in prebiotics could benefit your metabolic health, including cholesterol, blood sugar, and triglyceride levels.

A 2019 review that looked at 33 studies found treatment with prebiotics significantly reduced fasting blood sugar and insulin levels.


Adding prebiotic foods to your diet or supplement could help reduce inflammation markers.

In a 2017 review, 14 out of 29 prebiotic studies that were looked at showed a significant decrease in at least one marketer of systemic inflammation. This could be due to the increase in short-chain fatty acids that help reduce inflammation by improving the health of the intestinal lining and preventing pro-inflammatory molecules from moving across your gut wall.

Reduced Cravings and Appetite

Along with prebiotic gut health benefits, these substances might reduce your cravings and appetite. You could especially find that specific cravings are reduced if you up your prebiotic intake, like cravings for sugary foods.

Reduced Body Fat

In a 2021 review looking at 27 studies, researchers concluded that symbiotics, combined probiotics, and prebiotics could help with fat loss and weight loss in people who were overweight or obese.

The Importance of a Healthy Gut

Understanding what prebiotics are good for relies on understanding gut health in general.

Gut bacteria play a role in human health. Gut bacteria can help supply nutrients, synthesize vitamin K, and promote nerve function. When your gut ecosystem undergoes abnormal changes because of factors like diet, lifestyle, illness, stress, aging, and the use of antibiotics, it can cause chronic diseases, including inflammatory bowel disease, cancer, obesity, and autism.

If you have a high-sugar or highly processed diet, it can decrease your gut bacteria and reduce the diversity, and that can lead to inflammation throughout your body. Chronic inflammation is thought to lead to diseases like cancer.

There are research links between gut health and mental health, endocrine disorders, cardiovascular disease, and autoimmune diseases.

Signs that your gut isn’t healthy and that you might consider the use of prebiotics or probiotics include:

  • Upset stomach with symptoms like bloating, constipation, diarrhea, heartburn, or conditions like irritable bowel syndrome.
  • Changes in weight that aren’t intentional, including weight gain or loss. If you lose or gain weight without changing your eating or exercise habits, you could have an imbalanced gut that’s impacting the ability to regulate blood sugar, absorb nutrients, and store fat. If you lose weight, this could be due to small intestinal bacterial overgrowth or SIBO. If you gain weight, it could stem from high levels of inflammation or insulin resistance.
  • If you have sleep problems, like short sleep duration, this could be due to imbalanced gut bacteria. Researchers think the link between problems with sleep and gut bacteria may stem from the connections to mental health, metabolic function, and inflammation.
  • When people have skin issues like psoriasis, it could indicate that they have lower amounts of beneficial bacteria in their gut, affecting their immune function.
  • Having autoimmune conditions could be due to gut issues or gut dysbiosis. When your gut isn’t healthy, it can increase systemic inflammation, affecting your immune system. Then, the result can be autoimmune conditions where your body is attacking itself instead of invaders.
  • If you have food intolerances, you have difficulty digesting certain foods. Food intolerance could be due to the poor quality of gut bacteria. You might have symptoms when digesting certain foods, including diarrhea, nausea, bloating, gas, or abdominal pain.

What Are Prebiotic Foods?

Some foods are naturally high in prebiotics; including them in your diet could help improve your gut health. Prebiotic foods include:

  • Onions
  • Leeks
  • Garlic
  • Tomatoes
  • Asparagus
  • Tomatoes
  • Bananas
  • Honey
  • Whole grains like wheat, rye, and barley
  • Chia seeds
  • Seaweed
  • Peas
  • Chicory root
  • Dandelion greens
  • Cow’s milk

While there are foods that contain prebiotics, there aren’t many that are naturally high in them. The foods highest in natural prebiotics, like artichokes, aren’t always something we regularly consume in our diets, so prebiotic supplements are an option to help gut health.

The Role of Short-Chain Fatty Acids in Health

When we talk about what prebiotics are good for and their benefits, it’s worth taking a more in-depth look at short-chain fatty acids and how they affect our health. Your friendly bacteria produce short-chain fatty acids or SCFA in your gut, and SCFAs are the primary source of nutrients for colon cells.

In the technical sense, a short-chain fatty acid has fewer than six carbon atoms, produced as your gut bacteria ferment fiber in the colon.

They provide around 10% of your calorie needs daily, and they’re involved in the metabolism of fat and carbs.

The body’s three primary short-chain fatty acids are butyrate, propionate, and acetate.

Propionate is involved in glucose production in the small intestine and liver. Acetate is for energy production and lipid synthesis, and butyrate is the energy source for the cells lining your colon.

SCFAs are thought to have anti-inflammatory and protective effects on the gut.

For example, human studies suggest that having enough SCFAs, particularly butyrate, can improve symptoms of conditions like Crohn’s disease and ulcerative colitis.

Short-chain fatty acids can also play a role in preventing and treating some types of cancer, including colon cancer. In lab studies, there’s evidence butyrate can promote the health of colon cells, prevent the growth of tumor cells, and encourage the destruction of cancer cells in the colon.

While it’s not fully understood why SCFAs have these protective effects, it could be because they can increase the expression of epithelial barrier-forming molecules. They might also influence immune cell production in the colon.

In animal and human studies, butyrate has been linked with better control of blood glucose levels and improved insulin resistance in people with type 2 diabetes.

Several observational studies link high-fiber diets with a lower risk of heart disease, and the association strength tends to depend on the type of fiber and the source. One reason fiber intake might be linked to a reduced risk of heart disease is that the colon produces short-chain fatty acids.

Taking Prebiotic Supplements

Most aren’t associated with significant side effects if you take a prebiotic supplement to improve gut health.

One potential issue to be aware of is that taking large doses can lead to digestive symptoms like diarrhea, bloating, and gas, since prebiotics ferment in the large intestine. If you follow dosage instructions for the supplement, you shouldn’t have any side effects.

A typical dose of prebiotics would be 2.5 to 10 grams daily to get the most health benefits.

Even though prebiotic supplements aren’t considered dangerous, they’re not suitable for everyone. Some people might experience benefits and improved digestion. Other people may have no side effects, but some could experience bloating or similar symptoms.

Depending on the manufacturer of the supplement you’re trying, most recommend taking a serving once or more a day with food.

You can find prebiotic powders that you mix with a smoothie or yogurt.

There are also capsules.

Find a guide to what prebiotics are good for and how they help not just gut health.
Learn how prebiotics work and what they do for the body.
Why are prebiotics good for you? Find out with this gudie.

It is possible to overdo it with prebiotics, so start with a low dose and go slow as you’re starting out. It’s good to start with a small dose if you’ve never used a prebiotic supplement before and gradually work your way up, not exceeding the dosage instructions.

What about taking prebiotics and probiotics together? You don’t need a prebiotic to see the benefits of taking a probiotic, but you can maximize the benefits of a probiotic supplement if you combine it with one.

Frequently Asked Questions

The following are brief answers to some of the more common questions about prebiotics.

What Are Prebiotics for?

Your gut microbiome is a term used to refer to the microorganisms calling your intestines home. Everyone has hundreds of species of bacteria, viruses, and fungi in their digestive tract. A large variety of healthy gut bacteria making up your microbiome can reduce the risk of certain conditions such as inflammatory bowel disease and cancer.

A healthy gut microbiome is linked with more than just digestive health. A good mix of healthy gut bacteria can enhance immune function, reduce the risk of cardiovascular diseases, keep colon cells healthy, and even benefit brain function.

Prebiotics serves food for the bacteria that make up a healthy gut microbiome. Prebiotics are part of making sure that the bacteria in your gut are well-balanced for optimal health.

How Do Prebiotics Work?

Prebiotics are plant fibers that serve as fertilizers to stimulate healthy bacteria growth in your gut. Prebiotics are found in many whole foods like fruits and vegetables, especially when they contain complex carbohydrates like resistant starch. These aren’t digestible, so they pass through your digestive system, becoming food for bacteria.

If you don’t get enough from your food for a healthy microbiome, you might take prebiotics in supplement form.

Why Are Prebiotics Good For You?

Prebiotics are a source of food for healthy bacteria. As well as feeding your good gut bacteria and helping to improve digestion and bowel movements, prebiotics can help you absorb calcium and help you ferment foods faster. This will help the foods stay in your digestive system for shorter periods, so you don’t have constipation. Prebiotics are good for keeping your gut lining cells healthy and can help change the rate at which the food you consume spikes in your blood sugar.

Final Thoughts

Prebiotics can be something that you incorporate into your diet or supplement routine to improve your gut health. Prebiotics are different from probiotics, however. Prebiotics are like food or fertilizer for probiotics that can survive your digestive system. Prebiotics help create short-chain fatty acids, and they do promote a healthier gut microbiome, often when used along with probiotics.

Medically Reviewed By Christine Traxler MD

Medically Reviewed By Christine Traxler MD

Christine Traxler MD is a family physician, lifelong writer, and author with a special interest in mental health and the physical after-effects of psychological trauma.

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