Do I Need a Prebiotic Supplement?

Why You May Want to Think Twice Before Buying

Food sources of prebiotics

Getty Images/Jane Vershinin

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Your gut is a buzzing community made up of trillions of microorganisms known as the gut microbiome. Researchers are just starting to tap into the many wonders and benefits of this bustling city that lives in your digestive tract. 

Though the community of microorganisms living in your gut is as unique to you as your fingerprints, it’s changeable. Prebiotics and probiotics play a major role in helping to create that change — usually for the better. In fact, early studies indicate that the makeup of your microbiome may influence your risk of developing chronic diseases such as inflammatory bowel disease (IBS) or Type 2 diabetes.

You may know about probiotics, but what about prebiotics? Do you need a prebiotic supplement too?

What are Prebiotics?

Prebiotics are a type of fiber that serves as a source of food for the microorganisms (also known as probiotics) in your gut. The concept of prebiotics was first introduced in 1995 and described as a non-digestible food substance that stimulates the growth of the bacteria in the colon.

After some years of research, the International Scientific Association of Probiotics and Prebiotics (ISAPP) developed a new definition for prebiotics in 2008. They said a dietary prebiotic is “a selectively fermented ingredient that results in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefits upon host health.”

Julie Stefanski, MEd, RDN, CSSD, LDN, CDCES, FAND, is the owner of Stefanski Nutrition Services, senior editor for food and nutrition at Good-Heart Wilcox, and spokesperson for the Academy of Nutrition and Dietetics (AND). She says as prebiotics ferment, the bacteria in the gut create beneficial substances that nourish both the bacteria and intestinal cells. 

Most known prebiotics are oligosaccharides, which are carbohydrates your body has a hard time digesting. 

Examples of prebiotics

  • Fructans ― inulin and fructooligosaccharides (FOS)
  • Galactooligosaccharides (GOS)
  • Resistant starch (RS)
  • Polydextrose
  • Pectin 
  • Rhamnose

Though not a carbohydrate or type of fiber, a compound known as cocoa flavanol may also fit the definition of a prebiotic. There’s some evidence that this bioactive compound stimulates the activity of certain beneficial bacteria in the gut. However, more research is necessary.

The prebiotic supplements you find online or at your local health food store may contain one or more of these known prebiotics in various forms. For example, they may use chicory root as a source of inulin or potato starch as a source of resistant starch.

Benefits of Prebiotic Supplements 

Most high-fiber foods naturally contain prebiotics. Adults need 21 to 38 grams of fiber a day. It’s estimated that the majority of Americans fail to meet their daily fiber needs.

Dietary fiber offers many health benefits like improving bowel movements and lowering cholesterol. It’s also a source of prebiotics.

Unlike fiber, there's no official dietary recommendation for prebiotics. However, ISAPP suggests 3 grams of prebiotics a day to support gut health.

There's some evidence that prebiotic supplements may offer health benefits, such as decreasing anxiety and alleviating IBS symptoms. Researchers have also found that prebiotic-containing infant formula may improve early colonization of the the good bacteria in the baby's gut, setting the stage for the permanent microbiome that affects health throughout life.

However, before you start searching online for a prebiotic supplement to add to your daily routine, you may want to think twice before spending your money on a prebiotic supplement. 

Drawbacks of Prebiotic Supplements

Prebiotics benefit your health. But do you need to take a supplement? Before investing in a prebiotic supplement, you may want to know about the drawbacks. 

Limited Evidence

The Academy of Nutrition and Dietetics says the use of dietary supplements for disease prevention—like prebiotics—isn’t as beneficial as you might think. Further, the AND notes there’s not enough evidence to support that these types of supplements provide any long-term benefits. 

Additionally, most of the prebiotic supplement studies included only one known class of prebiotics — oligosaccharides. According to a review article published in the January 2018 issue of Current Developments in Nutrition, each known class of prebiotic fibers offers its own set of health benefits.

Though there's a lot of evidence to support the benefits of fermenting prebiotic fibers, like inulin and the oligosaccharides, the other types may be as beneficial, or even more so, according to the authors of the review.

Lack of Regulation

Unlike drugs, the FDA doesn’t regulate dietary supplements or require manufacturers to prove that their supplements work before they hit the shelves. Supplements may contain active or hidden ingredients that negatively affect the body or interact with other medications

Unpleasant Side Effects

You may also experience unpleasant gastrointestinal side effects from the prebiotic supplements. Because they are a type of fiber, they may cause gas and bloating. However, these side effects may depend on your usual fiber intake and the dosage of your prebiotic supplement.  

Poor Substitute for Real Food

Dietary supplements are like insurance. They ensure your body gets the nutrients it needs to function properly. However, supplements are no match for the nutrients you get from real food and are not a good substitute for a balanced, varied diet.

According to Stefanski, when you take out a single nutrient from food and put it into a supplement you lose the “synergistic benefits” you get from the other substances found in the whole food. In other words, it would be better to eat asparagus or bananas, two foods that are rich in prebiotics, but also provide other key nutrients.

Not a Good Fit for Your Gut

The balance of microorganisms in your gut affects your health and may determine how well you tolerate a prebiotic supplement. 

“Newer research shows that in certain gastrointestinal conditions the balance of bacteria may not be the same as in individuals with good intestinal health. When certain families of bacteria are too high or too low, fermentation of a prebiotic fiber may produce excessive gas, bloating, and pain,” says Stefanski.

You should always talk to a health care provider about nutritional supplements before adding them to your daily routine. 

When it comes to prebiotic supplements, there's simply not enough evidence that they offer any health benefits.

Food Sources of Prebiotics

Instead of wasting your money on a supplement that may not work and might cause you to feel bloated, why not add natural sources of prebiotics to your diet.

  • Dandelion greens
  • Asparagus
  • Onions
  • Garlic
  • Apples
  • Watermelon
  • Peas
  • Chickpeas
  • Cashews
  • Oats
  • Barley
  • Wheat bran

Foods rich in prebiotics are also good sources of other health-promoting nutrients like dietary fiber, vitamins, and minerals.

What About IBS?

If you have IBS and follow a low-FODMAP diet, you may be a bit wary about adding any of these foods to your diet. Most of these prebiotic-rich foods are also high in the short-chain carbohydrates (also known as fermentable oligo-, di-, monosaccharides, and polyols or FODMAPs) you need to avoid to ease your IBS symptoms. 

However, the low-FODMAP diet is a temporary, elimination diet that helps identify the foods that may or may not contribute to your IBS symptoms. It’s not a long-term diet plan. You should only follow the low-FODMAP diet under the direction and guidance of your health care provider and registered dietitian.

A Word From Verywell

At Verywell Fit, we aim to provide the facts behind the fads, especially when it comes to products and health habits that are popular but may not be entirely rooted in science. When it comes to herbal remedies and supplements, including items like prebiotics, be a cautious consumer.

While there are some purported health benefits of products like prebiotics, the science is limited. Instead of reaching for a product that may not provide everything the label claims, we suggest looking to adequate fiber and hydration, balanced nutrition, good sleep hygiene, daily movement, and other positive lifestyle factors to ensure you feel your best.

12 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Jill Corleone, RD
Jill is a registered dietitian who's been learning and writing about nutrition for more than 20 years.