What Are Prebiotics?

Prebiotics are starting to grab some of the gut-health glory reserved for probiotics, the beneficial bacteria that yogurt made famous. Now prebiotics — the food for the good bacteria already living in our gut — are popping up everywhere.

Probiotics vs. prebiotics: While these two words sound similar — with only a single letter that differs — probiotics and prebiotics play distinctly different roles in supporting gut health. Probiotics are the actual live microbes or beneficial bacteria. Prebiotics are the food for these beneficial bacteria.

To remember the difference between probiotics and prebiotics, take this advice from Hannah D. Holscher, an associate professor of nutrition at the University of Illinois: “When I think about prebiotics, I remember the ‘e’ for the energy they provide for gut bacteria. And for probiotics, I think of the ‘o’ for organism in the gut microbiome.”

The other key difference between the two is that prebiotics aren’t alive, so as a food option, they’re more easily available for us to eat. “Unlike probiotics that must be alive at consumption, prebiotics are food constituents that are stable and therefore more amenable to include as part of one’s diet,” says Robert Hutkins, a professor of food science and technology at the Food Innovation Center at the University of Nebraska-Lincoln and one of the country’s leading experts on prebiotics.

[READ: Fermented Foods: Myth vs. Fact.]

Health Benefits of Prebiotics

“Prebiotics are finally having their moment,” says Kara Landau, “The Prebiotic Dietitian” who is the founder of Gut Feeling Consultancy. “Consumers now realize there is another piece to the gut health puzzle beyond probiotics.”

Mintel’s Global New Products Database reveals that 39,063 new food and beverage products with prebiotic ingredients have been introduced in the last five years.

The main benefit of prebiotics is to nourish the good bacteria in our gut, which helps provide a better balance in our microbiome. Studies with prebiotics have documented numerous potential health benefits. For instance, a high prebiotic intake is associated with reduced gut inflammation, alleviation of constipation and overall digestive health. Certain prebiotic fibers may also help with satiety and therefore help with weight management. Plus, consuming prebiotics regularly and consistently may help fight off harmful bacteria in the gut and support immunity.

Other studies suggest some prebiotics may have a positive impact on blood cholesterol and triglycerides, improve calcium absorption and reduce blood sugar levels. Different types of prebiotics are linked to different benefits. A recent Gut Feelings trial found that a high-prebiotic dietary intervention may improve mood, anxiety, stress and sleep in adults with moderate psychological distress and a low prebiotic intake.

Feeding your microbes to promote mental well-being is a growing field known as psychobiotics. With a recognized gut-brain connection, researchers suggest prebiotics may offer new avenues for leveraging the gut microbiome to enhance mental health.

[See: Ways to Shift Your Mindset for Better Weight Loss.]

Defining Prebiotics

In a similar way that probiotics is scientifically defined, there is a scientific definition of prebiotics. To meet the criteria, a prebiotic must selectively nourish the beneficial bacteria and not provide a blanketed boost to all gut bacteria.

A prebiotic must also be present at a significant level and provide a demonstrated health or performance benefit, according to the International Scientific Association of Probiotics and Prebiotics (ISAPP).

It’s not always easy to determine the amount of prebiotics in products since nutrition labels will list grams of total dietary fiber, but not all of the fiber in a food will be prebiotics.

[READ: Best Diets for Seniors.]

Types of Prebiotics

There’s a good chance you’re already getting some prebiotics in your diet. Prebiotics are naturally found in fruits and vegetables, including onions, garlic and asparagus. Whole grains are another major source of prebiotics in the American diet — from oatmeal and other breakfast cereals to whole-wheat bread. Getting adequate amounts of prebiotics may mean maintaining a diverse diet rich in plant-based foods, which will also benefit overall health.

One type of prebiotic is resistant starch, a type of carbohydrate that resists digestion but helps ferment in our gut to feed beneficial bacteria. Food sources include green bananas and plantains, beans, peas and lentils, whole grains, cooked and cooled rice, pasta and potatoes.

Beta-glucans are a second type of prebiotic. Sources include oats, barley, mushrooms, algae and other marine plants. Other foods recognized as having prebiotic properties include almonds, chia seeds, flaxseeds, dandelion greens and artichokes.

Inulin is a dominant type of prebiotic. The major food sources of inulin include chicory root, Jerusalem artichokes (or sunchokes) and agave, which is why you’ll often see these listed as ingredients in prebiotic foods and beverages. Inulin also occurs naturally in leeks, garlic, asparagus and jicama.

Inulin is also commonly available as fiber supplements, including in capsules, gummies and powders. You can add the powder to smoothies, a bowl of oats or your morning coffee to easily boost your daily intake. If you go the supplement route, do the research, Holscher recommends. Choose a high-quality supplement from a company that follows good manufacturing practices and does independent lab testing on its products to help maintain quality and purity.

Prebiotic Misinformation

With the growing recognition of the health benefits of prebiotics, it’s no surprise that companies are adding prebiotics to foods and beverages — from prebiotic sodas and other drinks to yogurts, bread, cookies and desserts.

Some of these products are making bold promises, calling prebiotics your “metabolic miracle” and “detox powerhouse.”

Jaclyn London, a New York City-based registered dietitian, podcaster and food industry consultant, is skeptical of some gut health marketing, especially how apple cider vinegar is being touting as a prebiotic. Apple cider vinegar, frequently referred to as ACV, is not a prebiotic, and it does contain the pectin found in apples, according to the Global Prebiotic Association.

Even so, some prebiotic sodas erroneously tout the prebiotic benefits of ACV. This type of misinformation is one of the reasons why the Global Prebiotic Association and Nutrasource are introducing a Prebiotic Verified seal to help consumers distinguish the truly functional prebiotic products on the market from those that are simply marketing, says Landau.

“It is important to seek recommendations from trusted sources such as registered dietitians or brands that are backed by science to ensure what you are consuming will actually offer you the claimed benefits,” she says.

As an example, Landau says some baked products that use green banana or tigernut flour as a source of prebiotics may not actually contain prebiotics because these sources of resistant starch are not heat stable and the prebiotic benefits would be lost during baking. A product like this would not qualify for the Prebiotic Verified seal, which is intended to help identify products that have a true prebiotic function in their final format, she says.

Recommended Dose of Prebiotics

Research shows there may be a health benefit from as little as 5 grams of some prebiotics per day. But instead of zeroing in on a certain number, you might aim to get a variety of different sources throughout the day.

“Many fiber-rich foods have prebiotic activity, so if you follow the Dietary Guidelines for fiber (25 grams per day for women and 38 grams for men), you will get plenty of prebiotics,” says Hutkins.

Yet, only 1 in 1O U.S. adults meet the daily fiber recommendations.

London recommends starting with naturally occurring prebiotics in whole foods. “While we all love convenience — myself enthusiastically included — we simply don’t have evidence that supports the idea that we’ll get the same benefits from consuming these compounds as additives in food products vs. consuming more of the wholesome versions of these foods as part of an overall nutrient-dense eating pattern,” she says.

Landau agrees as well. She suggests eating a variety of prebiotic types from various sources. When you rely on a prebiotic soda or other fortified products that contain one purified prebiotic, you risk not nourishing the hundreds of probiotic strains in your gut microbiome that need diverse prebiotics to be adequately fueled, she says.

Here’s where some of the prebiotic-fortified foods and supplements could help you increase your intake of prebiotics.

You may, however, find that drinking a prebiotic soda floods your body with a heavy dose of prebiotics too quickly (some contain 9 grams per serving), which could cause gas, bloating and diarrhea, says London. For example, if you’ve ever experienced gas and bloating after eating a high-fiber granola bar, yogurt or another food with added inulin or chicory root, you probably ate too much fiber too quickly. Start with small amounts and increase until your body is used to it.

The Take-Home

While prebiotic sodas may be a better alternative to sugary soft drinks, and certain prebiotic foods may be a nutritious snack, they shouldn’t be the main source of prebiotics in your diet.

The best approach is to eat a variety of fruits and vegetables, beans, nuts, seeds, whole grains and fermented foods to help nourish your gut — and to support your overall health. Focus on meeting daily recommendations for these plant-based foods and those prebiotics will follow.

More from U.S. News

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Foods That Cause Bloating

10 Fiber-Friendly Food Swaps to Help You Lose Weight

What Are Prebiotics? originally appeared on usnews.com

Update 04/11/23: This story was previously published at an earlier date and has been updated with new information.

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