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Probiotics explained: What to know before you buy

A gastroenterologist explains what probiotics really do and whether they're worth the money.

Probiotics in milk or yogurt
Probiotics are beneficial bacteria found in foods or supplements.
Getty Images

Gut health is seriously buzzy in the health world right now and one thing that's almost always a part of that conversation is probiotics. Take a walk through any health store or pharmacy and you're likely to see rows and rows of different kinds of probiotic supplements promising to improve digestion and your overall health. And they aren't cheap, often costing upwards of $20 or more per bottle. In fact, the probiotic push is so high, the market is expected to reach $73.8 billion by 2024. 

Read more: Why does my stomach hurt? Common causes and when to see a doctor

Simply put, probiotics contain live bacteria that are meant to help populate "good" bacteria in your gut microbiome. The idea behind probiotics is that a healthy gut microbiome can be conducive to better overall health and may help specific conditions like irritable bowel syndrome (IBS) or even vaginal yeast infections. But, the science behind these bugs is quite controversial and a lot of studies are still underway to fully understand how they work. 

To shed some light on the topic, I tapped a gastroenterologist and gut health expert, Dr. Will Bulsiewicz to explain how probiotics work and help you figure out if they are right for you. 

What do probiotics do?

When it comes to probiotics, it's important to understand that there are a plethora of different strains of probiotics that can all have potentially different effects on your body. So even though it is difficult to explain how each strain works, the concept behind the popular probiotics on the market is similar -- to populate healthy bacteria in your gut. 

"The theory with probiotics is that they mimic the effects of our intact microbiota. In other words, just like our healthy gut microbes, these probiotics should optimize our immune system, reduce inflammation, inhibit the growth of pathogenic bacteria, correct leaky gut and restore gut barrier integrity, reestablish intestinal motility, even improve mood," Dr. Bulsiewicz says. 

You can purchase probiotics in supplement form, but they are also found naturally in food -- particularly food that is fermented. Examples of probiotic-rich foods include yogurt, kefir, kombucha and sauerkraut.

Since you can get probiotics from food, you might be curious about why you would even want to take a supplement. Besides the convenience factor, one benefit from probiotic supplements is that you can choose products with targeted strains for certain issues with a supplement. On the other hand, if you eat fermented foods you can still get probiotics, but you may not know exactly which strains or how much. 

So if you're looking into probiotics for a specific reason (i.e. IBS or constipation) then you may benefit from looking into specific strains of bacteria that can help with that. For example, Lactobacillus rhamnosus GG is a probiotic strain that researchers found particularly helpful for diarrhea. Another thing to note is that probiotic supplements do not have to be approved by the FDA before they are sold. Otherwise, for the general benefits, eating probiotic rich foods like yogurt each day can do the trick. 

Who should or shouldn't take probiotics?

Although technically anyone can take them, there are certain groups of people who can benefit the most from probiotics. For example, they have been studied for the potential to help with a wide variety of ailments like diarrhea, and urinary tract infections (UTIs), just to name a few. And they are considered relatively safe for most people. 

"Probiotics have been used widely for decades now by the general population, and the safety record has been excellent in both health and disease," Dr. Bulsiewicz says. 

fermented foods rich in probiotics

Fermented foods like sauerkraut and kimchi are natural sources of probiotics. 

Getty Images

There are also certain groups of people who could be vulnerable to issues or complications from taking probiotics, which is why you should always consult your doctor before starting any supplement, including probiotics. According to Dr. Bulsiewicz, some studies found that there is increased risk of complications for people with severe acute pancreatitis who took probiotics, and some people with motility disorders had issues with severe brain fog, gas and bloating. 

"This may sound scary, but consider the millions of people taking a probiotic on a daily basis for decades now, and that these possibilities are at the most extremely rare. To me, the main question with probiotics is not their safety. The main question is whether the benefit of the probiotic is worth the cost, which frequently runs $40 to $60 per month," Dr. Bulsiewicz said.

Are probiotics worth buying?

The science on probiotics is promising at best, but there's just a lot that we don't know yet. For example, scientists don't know for sure which specific strains of probiotics are most helpful and how much you actually have to take to see benefits. According to the National Center for Complementary and Integrative Health, there are not many in-depth or detailed studies on probiotic safety.

According to Dr. Bulsiewicz, even though probiotic use is widespread and relatively safe, he is uncertain that most supplements actually do what they claim. 

"The bottom line is that you want and should expect results from your probiotic. Unfortunately, many do not get results, and are left confused and frustrated that they spent so much money. To increase the odds of success with a probiotic, you should opt for the strain and quantity that has been proven in study to work for whatever medical condition you are trying to address," Dr. Bulsiewicz says. 

The best way to do that is to consult with your doctor and or a dietician or nutritionist to figure out which strains of bacteria may be beneficial to you. That way you aren't wasting precious time and money taking supplements that may not even target the issue you are hoping to improve.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.