I’m a gut health expert. These are the probiotics worth taking — and how to increase your intake of ‘good’ bacteria through food.

Navigating the vast amount of probiotic supplements on the market can be tricky. Probiotics are bacteria that live inside our body and are also found in fermented foods like, yogurt, cottage cheese, buttermilk, and pickles preserved in saltwater. There are thousands of different strains of probiotics that each play a role in maintaining equilibrium in our bodies, from gut health to vaginal health to mental health.

Many of these strains are available for purchase in supplement form, too, but the majority lack research on whether they improve gut health, Insider previously reported . Despite the lack of research, the $60 billion probiotic supplement industry is expected to grow by 9% every year until at least 2028. Dr.

Alexandra Shustina, a board-certified gastroenterologist and internist and founder of Whole Gut Health , told Insider researchers still have a lot to learn about how probiotic strains impact the body. Above all, eating a balanced diet with fermented foods offers the most benefits for your gut, Shustina said. “I don’t believe supplements are necessary for healthy people if they are getting what they need from their diet, which is absolutely possible, but they need to be educated on what to eat,” Shustina said.

That said, for those who could benefit from a boost — such as people with IBS — here are Shustina’s tips on how to make decisions when shopping for probiotic supplements: In her practice as a gastroenterologist, Shustina said she commonly sees patients with irritable bowel syndrome. Irritable bowel syndrome , or IBS, is a disorder that impacts 10-15% of adults and causes diarrhea, constipation, gas, bloating, and abdominal pain. Shustina said the two probiotic strains that are used to treat IBS are lactobacillus rhamnosus GG, lactobacillus plantarum, bifidobacterium bifidum.

Certain probiotic strains can help people who are taking antibiotics to treat an infection, since, as it tries to kill the bad bugs causing the sickness, antibiotics can inadvertently kill off the “good bugs” that live in our body, too, causing an infection. Reintroducing the saccharomyces boulardii organism can mitigate those side effects. Probiotics can also alleviate the symptoms of eczema , a common skin condition that causes red, itchy flare ups.

Shustina said lactobacillus species of probiotics, particularly lactobacillus rhamnosus GG, can help people with eczema. For most adults, Shustina said the best way to keep your gut healthy is through a probiotic- and fiber-rich diet. Fiber is sometimes called a ” prebiotic ” because humans cannot digest it but bacteria can.

Bacteria can use the fiber as fuel and live longer inside of the gut, helping the body with immunity and digestion . Sourdough bread, sauerkraut, kimchi, and yogurt are foods that contain enough probiotic strains for a healthy gut. The doctor also said people who don’t like those foods can easily ferment their own veggies in salt water.

Sleep , exercise , and stress maintenance also help to maintain a healthy microbiome, Shustina said. If your diet is low in probiotic-rich foods, and you’re struggling to up your intake, Shustina said to look for supplements that contain many types of lactobacillus strains, including lactobacillus acidophilus , and bifidobacterium strains. “You want to have a robust microbiome and diverse microbiome,” she said.

“You don’t want to have certain groups more than there are supposed to be. ” Since the supplement industry is largely unregulated , illegitimate sellers may offer pills that do not contain what’s listed on the bottle, according to Shustina. She recommends asking a doctor, health coach, or holistic medicine practitioner about professional-brand probiotic supplements or ones with good data to back up what’s in the product.

“Natural products in some ways are similar to pharmaceutical products — you have to know what you’re doing,” she said. “If you are not sure, food as medicine is always safer. So using food as medicine, especially if you’re healthy, is usually to be the first line.

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