Just when you get a handle on all the health and wellness trends out there, some new concept comes along that brings you back to square one.

So, you’re probably familiar with probiotics — you’re trying to eat the right gut-healthy foods or taking supplements that contain friendly gut bacteria — but a relatively new product with a similar name may have you all confused.

That’d be prebiotics. Wait, is that just a misspelling of probiotics? Or are prebiotics some kind of wellness snake oil sold by companies who want to ride the coattails of legit probiotics?

And — hold the phone — now there’s buzz about postbiotics?! With all the similar yet different terms swirling around, it’s time to clear up the confusion around what distinguishes each.

To understand probiotics’ role in your health, here’s a quick refresher on how they work in your digestive tract. A 2013 research review showed that your large intestine (and, to a lesser extent, your small intestine) is home to a population of bacterial microbes — more than 100 trillion of them.

Benefits of probiotics

These trillions of itty-bitty gut bugs have a major impact on your well-being, as a diverse colony of “good” bacteria promotes healthy digestion, while “bad” bacterial strains can cause digestive distress.

But it’s not just smooth bathroom business that makes a thriving intestinal colony so desirable. The microbiome (a term for the total of bacteria inhabiting your body) has lately become one of science’s hottest topics.

There’s research linking healthy gut microbes to reduced risks of health conditions including:

Probiotic-rich foods

With all that’s on the line, it’s not shocking that consuming gut-friendly foods and probiotic supplements is becoming popular.

These positive strains of bacteria exist naturally in unpasteurized fermented foods.

Examples of fermented foods include:

  • yogurt
  • kimchi
  • kefir (dairy and nondairy)
  • sauerkraut
  • tempeh
  • some unpasteurized pickled vegetables
  • kombucha tea
  • some cheeses

They can also be encapsulated in pills that deliver a massive dose in one shot — aka the over-the-counter (OTC) products most of us think of when we talk about taking probiotics.

Types of probiotics

If you start researching probiotics, you’ll notice different probiotic strains found on the labels. Here are some common strains:

  • lactobacillus acidophilus
  • lactobacillus rhamnosus GG
  • saccharomyces boulardii (a yeast)
  • bifidobacterium bifidum
  • bacillus coagulans

A research review showed that you may see multiple strains, or “cocktails,” used in products, especially if they’re targeting a specific ailment such as traveler’s diarrhea.

As researchers uncover deeper insights into how probiotics operate, they’ve discovered that there’s more we can do beyond inserting good bacteria into our systems via food or supplements.

For probiotics to work most effectively, it’s important to provide them with the best possible environment. (Don’t you want the little buggers to feel right at home?) That’s where prebiotics come into play.

In the simplest terms, prebiotics are food for probiotics. Your gut microbiome needs something to feed on while they’re hanging around your nether regions, and that something is “prebiotic” fiber.

This fiber is hardy enough to survive the first several stops along your digestive process (your mouth, esophagus, stomach, and small intestine) and make it to the end of the line (your colon), where probiotics live.

Therefore, prebiotic fibers are the so-called “nondigestible” varieties: oligosaccharides, inulin, and fructooligosaccharides, according to a 2013 research review.

But you don’t need to memorize that mouthful of nutrition-science vocabulary. Instead, remember that plant-based, high fiber foods — such as vegetables, fruits, grains, and roots — are good sources of prebiotics.

According to the Academy of Nutrition and Dietetics, these foods make the best choices:

  • asparagus
  • bananas
  • berries
  • dandelion greens
  • garlic
  • Jerusalem artichokes
  • leeks
  • legumes and beans
  • oats
  • onions

Synbiotic magic

A research review showed that some of those foods are called synbiotic because they have both probiotic bacteria and the prebiotic fiber on which it feeds. These include foods like kimchi, sauerkraut, and tempeh.

And now a word about the last type of biotics. Postbiotics, as their name implies, have to do with what happens after digestion. As bacteria “digest” the fibers in your GI tract, this activity produces metabolic compounds.

Though in the past, researchers thought of these postbiotics merely as waste byproducts, there’s rising interest in their potential as a medical therapy for inflammatory bowel disease, irritable bowel syndrome, and enterocolitis.

As the research is currently in its infancy, you won’t see postbiotics sold next to prebiotics and probiotics as dietary supplements any time soon.

But in a world where nearly anything can be distilled and put in a pill (even fecal transplants, according to a study!), it’s possible that postbiotic pills will eventually hit the market.

A research review showed that generally, both probiotic-rich foods and supplements are well-tolerated by most people. But in some circumstances, you may experience extra gas, bloating, constipation, or thirst.

Your best bet to prevent any tummy weirdness is to start low and slow with a dose that you can increase slowly. If the side effects continue or get worse, stop taking it and contact your healthcare provider for advice.

Antibiotics can do a number on both bad and good bacteria in your body, which can cause your gut to take a long time to recover.

Researchers are still trying to determine if taking a probiotic supplement after taking a course of antibiotics helps to replenish all of that good bacteria. The jury is still out.

One study showed that antibiotics can actually permanently change some types of bacteria. This can be especially true when taken during childhood.

In another study, taking probiotics to “bounce back” after antibiotics proved counterproductive because it made gut flora take longer to return to its “normal” state.

If you’re worried about antibiotics’ effect on your gut health, talk to your healthcare provider to see if they recommend any supplementation.

With our biotic terms defined, the question remains: Which of them should you take, and how?

If good bacteria benefit us so much, a billions-strong, OTC probiotic supplement may seem like an obvious choice. But as with most health information, it’s not so cut and dry.

One study raised serious questions around whether probiotic pills actually do what they’re purported to. In another study, many subjects’ digestive tracts resisted being colonized by probiotic supplements.

It’s important to know that resistance to colonization doesn’t mean that probiotics don’t work. But it does mean that you would have to keep taking them indefinitely to continue experiencing their benefits.

So, are probiotics are a bust? What are we to do if we want that all-important healthy gut?

“For a generally healthy person, I’d always recommend food first,” says Ali Webster, PhD, RD, associate director of nutrition communications with the International Food Information Council Foundation.

“Probiotic supplements have shown benefits only for very specific conditions, like antibiotic-related diarrhea, C. difficile infection, and necrotizing enterocolitis in infants. For other conditions, the evidence isn’t there.”

Webster points out that probiotic-rich foods also have “a lot of other beneficial compounds” that you won’t get in just a pill, like protein and calcium in yogurt and kefir, or vitamin C in sauerkraut.

As for prebiotics, you don’t necessarily need a pill to keep enough of them in your system either. And prebiotic-containing foods also boast plenty of important nutrients of their own, so Webster recommends getting them through food as well.

But if your diet doesn’t include many fruits, veggies, or whole grains, or poses certain macronutrient restrictions — (we’re looking at you, keto) — it may be wise to add a prebiotic supplement.

Probiotics and prebiotics are largely mysterious, but they could have potentially huge benefits if harnessed the right way. Science is still working on that part.

In the meantime, adding lots of fiber-rich fruits, veggies, legumes, and whole grains to your diet shows benefits for gut health and so many other parts of your bod. Adding more to your diet is a great way to help your microbiome be all it can be.

Finally, it’s a good idea to talk to a registered dietitian or other healthcare providers before taking a pre- or probiotic supplement (or any supplement), especially if you have any specific health conditions.