Prebiotics vs. probiotics: How can they help support gut health?

There’s an old saying: The way to a person’s heart is through their stomach. That’s true in more ways than one. So how does someone help their gut microbiome stay supported? That’s where probiotics and prebiotics can come in. Here’s some information about these two dietary components.

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What is the gut microbiome?

“The gut microbiome is a community of trillions of tiny living organisms,” says Mascha Davis, MPH, RDN, author of the book Eat Your Vitamins. “It plays a crucial role in human health.” The gut microbiome helps break down and absorb nutrients.

But it also has a much broader impact on the body. “The immune system, brain and many other body systems all rely on a healthy and diverse gut microbiome,” says Haley Bishoff, RDN, owner of Rūtsu Nutrition in Las Vegas.

What may probiotics do?

Probiotics are live microorganisms that may help support a healthy microbiome. Common ones include Lactobacillus and Bifidobacterium — so-called good bacteria — and Saccharomyces boulardii, a yeast. Many microorganisms found in probiotic supplement products are similar to the ones that naturally live in the gut, and they may also be available in certain foods.

Probiotic supplements may help restore the gut microbiome after being disturbed. “Introducing good bacteria into the gut creates competition between different types of flora and can push out harmful bacteria,” says Tina Marinaccio, RD, the owner of Health Dynamics LLC. There may also be potential benefits when using probiotics with conditions like antibiotic-related diarrhea, irritable bowel syndrome (IBS) and ulcerative colitis (UC). However, in most instances, it is still unknown which probiotics are helpful and which are not and how much is needed to benefit.

For those who struggle to get enough probiotics from their diet, taking supplements (in consultation with a health care provider) may be an option.

What foods and products contain probiotics?

Fermented foods are a good place to start. For example, yogurt is a fermented food that is considered a potential source of helpful probiotics. But not all fermented foods may have the same qualities.

While microorganisms may be used to make these foods, many of these foods do not contain probiotics with proven health benefits. Some popular fermented foods may include the following:

• Kimchi, a Korean fermented cabbage dish
• Kombucha, a fermented tea drink
• Many cheeses
• Miso, a fermented soybean paste
• Pickles
• Raw unfiltered apple cider vinegar made from apple sugars
• Sauerkraut

Dietary supplements can also be a way to increase a person’s intake of probiotics if enough isn’t gained through food. Be sure to speak with a health care provider before starting or stopping any type of supplement.

With so many options to choose from, Davis explains it’s best to consult a gastroenterologist or dietitian who specializes in gut health. Different products have different doses and bacterial strains.

What are prebiotics?

Prebiotics are usually complex carbohydrates, like inulin, that serve as food for beneficial microorganisms in the digestive tract. “Eating foods rich in prebiotics can help make the digestive tract work better overall and feed the healthy gut bacteria,” says Bishoff.

For those who struggle to get enough prebiotics from their diet, taking prebiotic supplements (in consultation with a health care provider) may be an option.

What foods and products contain prebiotics?

Prebiotics are often found in fruits, grains, nuts, seeds and vegetables. “This is a friendly reminder to incorporate a wide variety of high-fiber, plant-based foods in their natural form,” says Bishoff.

Sources of naturally occurring prebiotics can include the following:

• Bananas
• Cauliflower
• Oats
• Sweet potatoes
• Walnuts

The difference between prebiotics and probiotics

Prebiotic foods contain pieces that the body cannot digest, but which the microorganisms in the gut can break down and use for energy. Prebiotics can be thought of as healthy food for gut microorganisms. Probiotic foods, on the other hand, contain live, active microorganisms that help support the existing gut community. Probiotics act like teammates, working alongside other microorganisms to help keep the gut healthy.

The takeaway: Prebiotics and probiotics work together to help support a healthy gut.

How can people know if they’re getting enough prebiotics and probiotics in their diet?

There aren’t any official serving size recommendations for probiotics or prebiotics, so instead of stressing over numbers, people should focus on building a balanced diet.

Always remember to work with a health care provider when it comes to defining individual dietary goals.

How are probiotics measured?

Probiotics are measured in CFU, or colony‑forming units, which tells how many live microorganisms are in a product. On labels, people might see this written in scientific notation. For example, 1 × 10⁹ means 1 billion CFU, and 1 × 10¹⁰ means 10 billion CFU. But more CFU doesn’t automatically mean a product works better.

Right now, manufacturers are only required to list the total of microorganisms on a Supplement Facts label. That number can include both live and dead microorganisms. So, the number listed actually doesn’t tell people how many living probiotics they’re getting.

It’s best to choose products that list the CFU count at the end of shelf life, not just at the time they were made. This is because probiotics need to be alive to offer any benefit and they also naturally die off over time.

Key takeaways

Prebiotics and probiotics both play important roles in supporting gut health, but they work in different ways. Probiotics are live microorganisms that may add to the community of good bacteria in the digestive tract, while prebiotics can be specific fibers that feed these microbes. Including a variety of probiotic- and prebiotic-containing foods in the diet may help to support the gut.

Focusing on a diverse, balanced diet is more important than tracking exact amounts. Supplements can be considered if dietary intake is deemed insufficient by a health care provider, so it’s best to consult a health care provider about any questions or concerns. Ultimately, prebiotics and probiotics can work together to help support the gut microbiome and more.

FOR THIRD-PARTY LAB TESTING: A product sample is tested by an independent third party for certain contaminants and, whenever possible, the identity and potency of dietary ingredients. Dietary supplements must contain the amounts declared on the finished product label in compliance with the Dietary Supplement Health Education Act (“DSHEA”). Probiotic items are tested to ensure the colony forming units (CFU) count of each strain of live microorganism is present at the time of production. Excludes products that may be dispensed by the pharmacy. Supplements that are part of a home test kit in limited stores are also excluded. Tests performed on a single lot of the vitamin or supplement. As a result, we cannot confirm that subsequent lots would pass these tests. Learn more.