The 5 Key Benefits Of Probiotics

These gut-healthy supplements are key.

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What are all the benefits of probiotics? Docs weigh in.
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Probiotics are basically the Cher Horowitz of the gut health world. The active cultures, which usually have long names like Lactobacillus and Bifidobacterium and are found in food and in supplement form, are one of the most popular ways to improve your digestion woes. But what do these bacteria actually do for your health? And what are all the benefits of probiotics?

“Probiotics are live microorganisms — bacteria and yeast — found in specific foods and supplements and can be beneficial to humans,” says Dr. Erin Stokes, a naturopathic doctor and medical director at MegaFood. You can get a good dose from foods that list “live and active cultures” or snacks that are well-known to contain good bacteria. “Probiotics are found in fermented foods such as yogurt, tempeh, kombucha, kefir, kimchi, sauerkraut, and miso,” Stokes tells Bustle.

If you don’t really eat these foods or if you want to boost your probiotic intake beyond the occasional cup of yogurt, then a daily supplement might be a good idea. Before stocking up, one thing to keep in mind is that probiotics are identified by their specific strain, which can get as specific as an alphanumeric strain designation, Stokes explains. An example of this is the MegaFood Probiotic which has strains like Bifidobacterium lactis (SD-5219), which you can see on the back of the label.

Since different strains are helpful in different ways, registered dietician Sarah Glinski, RD suggests looking at the Probiotic Guide for more info. “This app allows you to search which probiotics have been scientifically shown to help with different health conditions so that you can make an informed and evidence-based choice,” she tells Bustle. With all that said, here are the benefits of probiotics — some of which you may not have known about.

The Benefits Of Probiotics


1. Improved Digestion

Having a healthy probiotic colony within your system — aka a healthy gut microbiome — promotes better digestive health by aiding nutrient absorption, says Stokes. This is why you often hear that probiotics are good for your digestion or that they help you stay regular.

2. IBS Relief

This one’s for you hot girls with IBS: Probiotics may also help support gut health by suppressing the growth of “bad” gut microbes while strengthening the gut barrier, says Glinski. “Certain strains of bacteria, such as Bifidobacterium 35624 — have been shown to provide relief of IBS symptoms like abdominal discomfort, gas, and bloating,” she tells Bustle.

3. Stronger Immune System

Your gut health is intricately tied to your body’s immune system. “Our gut microbes help develop and regulate our immune system, and the immune system affects the composition of our microbiota,” says Glinski. That’s why gut health plays a role in overall health.

“A healthy intestinal barrier is an important part of ensuring that the gut and the immune system ‘talk to each other’ properly,” Glinski adds. “One key part of this barrier is proteins called ‘tight junctions.’ These proteins control what gets through the gut barrier.” And research has found that certain probiotics help regulate these tight junctions.

According to Ashley Hawk, a registered dietitian, Lactobacillus fermentum is a strain that may support the immune system. While more research needs to be done to see how different probiotics affect humans, it’s looking like there are many ways in which they can help support immune health, including through regulation of the gut barrier and mucous layer, Glinsky says.

4. Mental Health Support

Gut health is so important to overall health that it may even play a role in mental health thanks to the gut-brain axis. “We know that there is two-way communication between the central nervous system and the gut microbiota, so in theory, changes in your gut microbiota — for example, by taking probiotics — could result in changes to your mental state,” Glinski says. While more research needs to be done and probiotics aren’t currently recommended to treat mental illness, some clinical studies have shown that probiotics may benefit depression and anxiety.

5. Vaginal Health

According to Rachel Fine, a registered dietician and owner of To The Pointe Nutrition, some clinical studies have shown that certain probiotics may reduce the colonization of bacteria and yeast in the vagina, specifically the oral use of Lactobacillus rhamnosus GR-1 and L. fermentum RC-14, resulting in better vaginal health. “But realize probiotics have not been known to prevent or treat such infections,” she says.

Delivery Methods

Remember, you can introduce healthy bacteria into your gut by eating foods like yogurt and kimchi. To get the most benefit from yogurt in particular, Fine recommends choosing one that’s packaging says “contains live cultures” or “active cultures” rather than “made with live/active cultures” as the latter could signal that the cultures were destroyed with heat-treatment during processing.

If you’d like to add more probiotics into your life via a supplement, then look for capsules, coated beads, or tablets, Hawk suggests. Coated tablets will ensure the bacteria make it to the correct place in your gut, though Hawk adds that the delivery method isn’t as important as the quality of the product.

How To Choose A Probiotic Supplement


Fine recommends looking for supplements that contain a mixture of bacterial strains rather than a single one. And because you’re dealing with live and active cultures, she says it’s helpful to look into how many organisms are expected to be “viable by the time you consume it,” since some bacteria can die during processing or might not be active by the time you take it. It’s also good to store probiotics in the fridge so they last up until the expiration date.

When looking at the labels, check for the CFUs or colony forming units, Hawk adds. The number of CFUs will depend on the strains the probiotic bottle contains. “More strains equal a higher total CFU,” Hawk says. “Start with a lower number and increase as you can tolerate it.”


The recommended intake for probiotic supplements varies by strain and specificity of use, says Fine. That said, “it tends to be about 1 billion to 10 billion cells, or CFUs, per day,” she says. “They should be taken on an ongoing basis for general benefits.” Ask your doctor if you aren’t sure how many to take or which strains might be most helpful.

Side Effects

When you first start taking a probiotic supplement, you might notice that you have a temporary increase in gas or digestive issues, Fine says. “Also, there is the possibility of allergic reactions,” she adds. “For example, individuals with milk allergies should be aware of probiotics that contain lactose fermenting bacteria — like Lactobacilli and Bifidobacterium.” But for the most part, probiotics are well-tolerated — so throw back a few billion and see how you feel.

Studies referenced:

Ansari, F. (2020.) The Effects of Probiotics and Prebiotics on Mental Disorders: A Review on Depression, Anxiety, Alzheimer, and Autism Spectrum Disorders. Curr Pharm Biotechnol. doi: 10.2174/1389201021666200107113812.

Barbosa, RSD. (2020.) Probiotics and prebiotics: focus on psychiatric disorders - a systematic review. Nutr Rev. 2020 Jun 1;78(6):437-450. doi: 10.1093/nutrit/nuz080.

Blackwood, BP. (2017.) Probiotic Lactobacillus Species Strengthen Intestinal Barrier Function and Tight Junction Integrity in Experimental Necrotizing Enterocolitis. J Probiotics Health. doi: 10.4172/2329-8901.1000159.

Brenner, D.M. (2009). Bifidobacterium infantis 35624: a novel probiotic for the treatment of irritable bowel syndrome. Rev Gastroenterol Disord. https://pubmed.ncbi.nlm.nih.gov/19367213/

Hills, RD Jr. (2019.) Gut Microbiome: Profound Implications for Diet and Disease. Nutrients. doi: 10.3390/nu11071613.

Reid, G. (2003.) Oral use of Lactobacillus rhamnosus GR-1 and L. fermentum RC-14 significantly alters vaginal flora: randomized, placebo-controlled trial in 64 healthy women. FEMS Immunol Med Microbiol. doi: 10.1016/S0928-8244(02)00465-0.

Krajmalnik-Brown, R. (2012.) Effects of gut microbes on nutrient absorption and energy regulation. Nutr Clin Pract. doi: 10.1177/0884533611436116.

Lerner, A. (2019.) Probiotics: If It Does Not Help It Does Not Do Any Harm. Really? Microorganisms. doi: 10.3390/microorganisms7040104.

Rao, RK. (2013.) Protection and Restitution of Gut Barrier by Probiotics: Nutritional and Clinical Implications. Curr Nutr Food Sci. doi: 10.2174/1573401311309020004.

Yan, F. (2011.) Probiotics and immune health. Curr Opin Gastroenterol. doi: 10.1097/MOG.0b013e32834baa4d.


Dr. Erin Stokes, naturopathic doctor and medical director at MegaFood

Sarah Glinski, RD, registered dietician

Ashley Hawk, registered dietitian

Rachel Fine, registered dietician and owner of To The Pointe Nutrition

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