Probiotics Can Make You Feel Sick In Some Cases, Experts Say, & Here’s What To Do If That Happens

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If you're trying to keep your gut health in check, you're probably already riding the probiotic wave. From yogurt and kombucha to dietary supplements, you can easily find probiotics in many common food items at your local grocery store. Though proven to have a number of health benefits, probiotic supplements can have surprising negative side effects in some cases that you shouldn’t ignore.

Simply put, as Healthline reported, probiotics are “friendly bacteria” (aka, living microorganisms) that are found in different dietary products, and there are hundreds of different strains; some researchers have even estimated there are thousands. These bacteria are similar to the ones that already live in your body — the same bacteria that are key to a healthy gut. Research has discovered that gut health (and these bacteria) plays crucial role in maintaining your overall physical and mental health. What’s more, a 2018 study found that probiotics could help counteract the effects of liver damage.

However, according to Ali Webster, PhD, RD, the Associate Director of Nutrition Communications for the International Food Information Council Foundation, the existing research surrounding probiotics is still limited.

“Probiotics have shown some health benefits in specific groups of people and in some research studies, but in many cases these effects aren’t consistent, or impressive enough to make a strong, evidence-based recommendation for taking them,” Webster tells Bustle. “That being said, some people may experience improvements in digestive health, or other conditions from taking a probiotic supplement or consuming more probiotic-rich foods, and usually the risk of side effects is minimal.”

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Though they're generally safe, that doesn’t mean probiotics are completely side effect-free. Webster says bloating and gas are among the most common side effects of probiotics. According to Medical News Today, this gassiness is due to changes in your microbiome, but these symptoms usually subside after a few weeks once your gut adjusts. However, a small study conducted in 2018 linked probiotics to bloating and brain fog due to overgrowth of bacteria in the stomach, or small intestine.

Bloating and brain fog are often temporary and not life-threatening issues, but, Webster explains that, “Probiotics could also cause some serious side effects for people with compromised immune systems.” According to the National Center for Complementary and Integrative Health, people with weakened immune systems, along with those who have underlying health conditions, or who’ve recently undergone surgery, are at risk of developing dangerous infections if they take probiotics, since they're re-introducing bacteria into their system.

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While probiotics supplements can cause some unwanted symptoms, the good bacteria in them aren't necessarily to blame if a new supplement is making you feel off. “Dietary supplements may contain other ingredients that could cause side effects separate from their active or advertised contents. For example, some probiotic supplements also include compounds derived from dairy, egg or soy, which are common allergens,” Webster says. “It’s important to read labels carefully.” Nevertheless, the FDA currently does not regulate supplements or vitamins, though earlier this year, the agency announced they would be imposing new standards for supplements to ensure safety and effectiveness.

Symptoms or not, Webster says it’s always a good idea to first check with your physician before adding a probiotic supplement to your daily wellness routine. Keep in mind that loading up on probiotic-rich foods and supplements aren’t the magical fix to gut issues, and could have side effects if you’re not ingesting the strains the unique microbiome in your belly needs. But chances are, you’ll feel fine if you eat one more yogurt a week — and if you're not, talk to your doctor about how to handle it.