Your Ultimate Guide to Gut Supplements: Probiotics, Prebiotics, and Postbiotics

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A Guide: Probiotics, Prebiotics, and PostbioticsTanja Ivanova - Getty Images

Supplements containing prebiotics, probiotics, and postbiotics are very hot, but the truth is, these nutrients and microorganisms are available through a well-rounded diet. What’s the difference between probiotics and prebiotics? What about postbiotics? Here’s what each P does for your gut.


These good-for-you live microorganisms, such as bacteria and yeast, live peacefully in your body, providing numerous health benefits and protecting you against other more harmful organisms. You can increase the ratio of good to bad bacteria through food (and supplements, if needed).

Health benefits:

Decades of research indicate that certain probiotics may ease constipation, prevent traveler’s diarrhea, and relieve IBS and ulcerative colitis symptoms. They may also help with atopic dermatitis, high cholesterol, and gum disease. But though there are many different kinds of probiotics, they’re not interchangeable: These microbes are strain- specific, meaning each type has unique health- promoting actions. So while Bifidobacterium infantis, Lactobacillus casei, or Lactobacillus plantarum may help alleviate IBS-related gas and bloating, you’ll want Lactobacillus rhamnosus GG (LGG) or Saccharomyces boulardii if your issue is antibiotic-related diarrhea.

How to get them from food:

The best sources of probiotics are fermented dairy products such as yogurt and kefir, which usually boast multiple strains of bacteria. Though you may have heard that other fermented products such as kimchi and sauerkraut also contain probiotics, that’s not exactly true, according to the National Institutes of Health—they do contain live bacteria, but their beneficial bugs lack sufficient strength and number to qualify as probiotics.

Should you supplement?

“If you’re looking for a specific benefit, such as improving glucose regulation, you want a supplement that contains the exact strain or strains that have been shown to be effective for that condition,” says Monica Reinagel, L.D.N., C.N.S., owner of Nutrition Over Easy in Baltimore. And while the American Gastroenterological Association doesn’t recommend taking probiotics alongside antibiotics in most cases, some doctors believe it is helpful. “Food is always best and should be prioritized, but I recommend supporting your gut with probiotics during a course of anti biotics, as probiotics have been shown to decrease the antibiotic-associated diarrhea and infection with C. difficile,” says Elena Ivanina, D.O., founder of the Center for Integrative Gut Health in New York City, who also recommends certain probiotics for patients with specific deficiencies in their microbiomes. Speak with your doctor before taking a supplement; the ideal dose can vary depending on the strain and product.


As helpful as probiotics are when you eat them, they pass through the digestive tract, so they work their magic only until you poop them out. If your goal is to improve your long-term gut health by growing more good microbes in your gut, consider prebiotics, the majority of which are essentially carbohydrates we can’t digest, such as fiber. These healthy carbs are like fertilizer for friendly gut bacteria.

Health benefits:

Prebiotics don’t confer specific benefits on their own; instead, they help gut bacteria work better. After you consume a prebiotic-containing food, its fiber travels to your colon, where the healthy microbes that live there (or any probiotics you’ve eaten) break them down for food. This provides fuel that helps your good gut microbes grow and multiply, enabling them to crowd out harmful bacteria. There’s another bonus: When these helpful bacteria thrive, they produce substances that nourish your colon and boost your immune system.

How to get them from food:

The best way to load up on prebiotics is by eating fiber-rich plant foods, especially bananas, asparagus, whole grains, onions, garlic, and soybeans. “One advantage to getting prebiotics from foods is that you can get many different types of fiber, and that in turn promotes a more robust and varied population of beneficial microbes,” says Reinagel. Dr. Ivanina recommends eating up to 30 different plant foods weekly to optimize your daily fiber intake—you’re aiming for roughly 25 g of fiber from food for women and 38 g for men. One day of gut-healthy eating may look like this: oatmeal and a banana for breakfast; a burrito bowl with brown rice, black beans, and sautéed onions and peppers for lunch; a large apple for an afternoon snack; and grilled salmon with roasted asparagus and quinoa for dinner.

Should you supplement?

While food should be your first course of action, there are times when a supplement can help, such as in the case of constipation or abnormal cholesterol, Dr. Ivanina says. Look for prebiotic fiber in supplements such as inulin, galactooligo saccharides (GOS), and fructooligosaccharides (FOS). Dr. Ivanina recommends starting with half the dose indicated on the label to see how your gut responds.


If probiotics and prebiotics had a baby, it would be postbiotics, substances your body produces after it feeds on prebiotics and probiotics. These include B vitamins, enzymes, amino acids, and short-chain fatty acids such as butyrate.

Health benefits:

While research is still in its infancy, postbiotics show promise for calming intestinal inflammation, easing constipation, managing allergies, boosting immune health, and more.

How to get them from food:

A probiotic- and prebiotic- rich diet, which can help you produce your own internal postbiotic supply, is a good start. And while kimchi and kombucha may not contain sufficient probiotics, they do provide postbiotics, as do yogurt, kefir, and other pickled vegetables.

Should You Supplement?

Possibly. “Like probiotics, postbiotics are pretty specific in their applications,” says Reinagel. “You want to match the postbiotic to the specific condition it’s been shown to benefit.” An additional upside: “Postbiotics are not live organisms, so they’re more shelf-stable,” says Reinagel. At the same time, since postbiotics are relative newcomers to the market, there are fewer options available. Two with solid track records are sodium butyrate (shown to calm IBS-related pain, bloating, constipation, and diarrhea) and Lactococcus lactis (for immune support and respiratory health).

The bottom line:

In most cases, all you need to support and maintain a healthy microbiome is a balanced, gut-friendly diet. “My strategy is to eat a wide variety of fermented, cultured, fiber-rich foods,” says Reinagel. “That way I’m introducing a wider variety of beneficial microbes and providing a nice buffet of different types of fiber to nourish them.”

Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure diseases. Be cautious about taking dietary supplements if you are pregnant or nursing. Also, be careful about giving supplements to a child, unless recommended by their healthcare provider.

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