If Your Digestive System Is Regular, Daily Probiotics Aren’t Necessary—Here’s Why

Probiotics are technically defined by the International Scientific Association for Probiotics and Prebiotics (ISAPP) as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” These little guys are kind of a big deal, linked to all kinds of benefits for your health and well-being. And you can find them in everything these days, from yogurts and teas to makeup and skin-care products to your traditional supplements. It's enough to make anyone wonder: Should you take probiotics, too?

I get this question a lot from clients; as a registered dietitian, it's my job to help people make decisions about what they put on their plates that's right for them and their unique needs. And understandably, people have a lot of questions about probiotics and whether they should try them, too.

Here's my hot take: If you’re dealing with specific GI concerns, incorporating a probiotic supplement might make sense for you. But if you’re taking a probiotic because you heard it was a good thing to do, well, you could likely skip it.

What do probiotics do?

Generally speaking, probiotics can help support a healthy digestion and immune system while cutting back on inflammation.

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How does that work, exactly? Well, your body houses trillions of microbes, with the overwhelming majority hanging out in your colon. Some of those bacteria are beneficial (like probiotics), and some of those bacteria are bad. (You can probably thank the bad guys for the gnarly stomach bug you picked up after eating wilted sprouts that one time...)

The overall makeup of your gut microbiome is a delicate balance; ideally, there are more beneficial gut bacteria than harmful ones. Eating foods high in fiber and prebiotics, as well as a wide variety of plants, can feed the good gut bacteria and help them thrive. But sometimes the bad bugs outnumber the good guys thanks to illness, poor diet, stress, and other factors¹. This is called dysbiosis, and is linked to everything from the mildly annoying (think: smelly gas) to the downright alarming, including a greater risk of allergies, autoimmune and hormonal diseases, and even colon cancer².

Regularly ingesting probiotics—aka eating extra servings of the "good guys," whether that's in food or supplement form—can help ward off dysbiosis.³ Probiotics also play a role in reinforcing the gut lining⁴, producing vitamins, neutralizing toxins, and producing short chain fatty acids, molecules that boast anti-inflammatory, anti-cancer, and cardioprotective⁵ benefits.

Do you really need a probiotic?

Ingesting probiotics is good for your gut and, by extension, your general health. But in my professional opinion, not everyone needs to take a probiotic supplement daily (or even at all), because they do come with some distinct downsides.

Ingesting probiotics is good for your gut and, by extension, your general health. But in my professional opinion, not everyone needs to take a probiotic supplement daily (or even at all), because they do come with some distinct downsides.

For starters, you have to be willing to take them daily to see any kind of benefit. Like medications, most need to be taken continuously in order for them to keep working. Research suggests that many probiotic strains in a supplement are inactivated by stomach acid, bile salts, and digestive enzymes⁶ on their journey down to the colon (though they may still deliver benefits). Even if probiotics do make it to their final destination, they likely only persist in the colon for up to a week. If you’re relying on a supplement to get your daily dose of beneficial bacteria, you’ll need to take—and pay for—that supplement for a while.

It's also important to note that digestive health is highly individual; there's no such thing as a one-size-fits-all probiotic. Two different people are bound to have different reactions to the same probiotic, thanks to the unique makeups of their respective digestive systems. And probiotics’ effects are strain- and dose-dependent, so it doesn’t make sense to pop any old capsule just for the sake of it. Since there’s no single benchmark for a healthy gut, it’s also tough to say which bacteria you’ll benefit from (if any) if you’re supplementing just to maintain good digestion.

Also good to know: Many probiotic supplements are now formulated as synbiotics, meaning they contain prebiotic fibers, like inulin or chicory root, in addition to probiotics. Prebiotics are crucial for optimal gut health, but they’re also notorious for causing gas and bloating, particularly among those with irritable bowel syndrome (IBS).

Probiotics’ effects are strain- and dose-dependent, so it doesn’t make sense to pop any old capsule just for the sake of it. Since there’s no single benchmark for a healthy gut, it’s also tough to say which bacteria you’ll benefit from (if any) if you’re supplementing just to maintain good digestion.

Who should take probiotics?

In general, most healthy adults shouldn't feel the need to take probiotics. But there are some instances in which you might want to consider taking them (with your doctor's sign-off, of course.)

So talk to your doctor first about what they think before popping a probiotic.

If you’ve been diagnosed with a GI condition or are experiencing ongoing digestive discomfort, work with a GI doc and registered dietitian who specializes in digestive disorders to determine the best treatments for you. There’s solid evidence that certain strains of Lactobacilli and Bifidobacteria (two broad categories of probiotic) may help improve symptoms of IBS. But taking a probiotic supplement isn’t the very first recommendation I make for those with IBS. Even the American Gastroenterological Association doesn’t recommend that all adults with IBS or IBD (which stands for inflammatory bowel disease) take probiotic supplements. (Because remember, gut health is super individualized!)

You can also talk to your doc about whether you should take a probiotic supplement if you’re starting a course of antibiotics. Doing so may help prevent side effects of the meds⁹. (It likely won't totally prevent dysbiosis though, as suggested by this 2023 study published in the journal BMC Medicine.)

Other evidence-based ways to keep your gut healthy

If you’re #blessed with healthy digestion and have been taking a daily probiotic because you thought it was a good thing to do, know this: there’s little risk in taking one but you also probably don’t need it. Instead, I suggest saving your money and instead getting consistent with these gut-friendly habits:

1. Eat as many different plant foods as you comfortably can

Research suggests that people who eat more than 30 different types of plant foods per week have more diverse (and presumably healthier) gut microbiomes¹¹ than people who eat less than 10 different types of plant foods per week. Fruits, vegetables, whole grains, nuts, seeds, herbs, and legumes are all stellar options for upping your plant intake. If you’re looking to incorporate more prebiotic foods, eat more garlic, onions, leeks, asparagus, and Jerusalem artichokes.

2. Consume fermented foods daily

Fermented foods that contain live microbes (think: sauerkraut, miso, kimchi, etc.) are outstanding sources of nutrients. And good news for the dairy girlies out there: Cultured dairy products like Greek yogurt and kefir contain legit probiotics and typically have the highest levels of beneficial bacteria of all fermented foods. Parfait.

3. Minimize ultra-processed foods, added sugars, and alcohol

No amount of probiotics will get your gut flora thriving if you’re feeding it an unvaried diet and drowning it in booze. A healthy relationship with food is flexible and allows for fun foods, but try your best not to make ultra-processed products,¹² added sugars¹³, and alcohol your go-tos. All three can seriously compromise gut health when consumed in excess.

4. Look beyond your plate

Eating a balanced diet is a key part of optimizing your gut health, but it’s not the only factor. Getting adequate and high-quality sleep and managing stress are also critical thanks to the oh-so-powerful gut-brain connection.

How to choose a probiotic

Again, most healthy people do not need to take a probiotic supplement; focusing on lifestyle and diet is a better way to support your gut health. But unless you’re immunocompromised (in which case you should always ask your provider before starting a probiotic supplement), it’s probably harmless for you to take one.

So if you really want to take a probiotic supplement for general health purposes, here are some tips for choosing a good one:

• Pick a supplement that’s made by a reputable brand that undergoes third-party testing by organizations like the National Health and Safety Foundation (NSF) or the United States Pharmacopeia (USP) to ensure the supplement contains what it says it does at safe doses. You’ll find indication that it’s third-party tested either on the product’s packaging or on the brand’s website.
• Choose a probiotic that contains strains that have been studied and shown to be effective for your primary complaint. For instance, some probiotics have been shown to be particularly helpful for relieving belly pain, while others are better at alleviating diarrhea. The U.S. Probiotic Guide is a helpful resource for this.
• Check how many colony forming units (CFUs) a supplement contains. You’ll want to be sure you’re taking an effective dose that’s supported by research. Don’t be freaked if the dosage sounds crazy high: CFUs typically range from 100 million to more than 100 billion per dose.
• Establish whether the supplement is a probiotic or a synbiotic. Some brands include non-fermentable (i.e. less gas-causing) prebiotics, but this isn’t the norm. Prebiotics are great for your gut, but if you’re someone who struggles with uncomfortable gas and bloating after eating prebiotic-rich foods like garlic and onion, you may do better opting for a plain probiotic over a synbiotic.