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by Steph Saullo RDN

January 14, 2019

Will probiotics help your belly perform at its best?

Probiotics have been around for some time; however, the evidence to support probiotic use and gut health is still in its infancy. The gastrointestinal tract can run up to 30 feet (9.1 meters) in length—that’s roughly one-third the length of a short course pool!

The gut is a little like an interior version of your skin, which has contact with the outside environment. Everything you consume makes its way through the GI tract, making it vulnerable to problems. Some of the most common include gas, bloating, diarrhea, constipation, and acid reflux (also known as heartburn). Eating nutritious foods such as fruits and vegetables, whole grains, lean proteins, and unsaturated fats will support a healthy GI tract, so are probiotics necessary as well?

Although there really isn’t any evidence to support probiotic use for athletic performance, there is research to defend the use of probiotics to improve certain conditions such as constipation, diarrhea, and symptoms of irritable bowel syndrome. Still, there are many different types and strains of bacteria and you can find probiotic supplements with multiple strains in various combinations, so what works?


Probiotics are live bacteria (“good” bacteria) that provide a benefit to the host (you). Probiotics can maintain a well-oiled GI tract that can include improvement of symptoms of IBS, enhance immune function, or they may protect the gut from harmful bacteria. It’s important to understand that taking probiotics will not automatically rid the gut of any and/or all “bad” bacteria. In fact, we all have some potentially harmful bacterial living in our gut and it may be important to help keep the peace among microbes.

All live bacteria are not necessarily probiotics and all foods that are cultured or fermented are not automatically considered probiotics. Remember to be classified as a probiotic, it must provide some health benefit. So if you’re into kombucha, kimchi, or sauerkraut for its supposed probiotic benefits, consider whether the food contains live microbes that have been shown to be beneficial. Also, if the product was pasteurized the microbes were likely killed and the product will not provide any probiotic effect.

Although foods such as yogurt or kombucha may have live strains of beneficial bacteria, the quantity of that bacteria is found in much smaller quantities than what you obtain from a probiotic supplement. This doesn’t mean that these foods aren’t good for you, we just don’t have adequate science to say that you’ll get the same benefit from those less potent doses.

Know What You Need

Don’t just select a random probiotic especially if you don’t have any GI issues. For general gut health maintenance or improving your gut health (but not for any specific symptoms), include a variety of bacteria in your diet. For most, obtaining probiotics in those smaller, less potent dosages from food sources such as yogurt kefir, sauerkraut, kimchi, soft cheeses, kombucha, and fermented soybean products (tempeh, miso, and natto) will suffice. Wine and beer are fermented too!

Bacteria Type

Recommendations for probiotics should include a genus, species, and strain to specify the bacteria. The most common groups (genus) of bacteria are Lactobacillus and Bifidobacterium. These groups each contain many types (species) of bacteria as well as different strains. Each do not offer the same health benefit. To treat a condition you’ll want to know what species has been shown to provide some benefit to a particular ailment (e.g., diarrhea, constipation, etc.).

For example, B. Longum infantis 35624 at a dose of 1 billion CFU per day may be helpful to alleviate constipation. B. longum 35624 at a dose of 1 billion CFU per day may be helpful for IBS. For more information about which bacteria may help with various symptoms visit the U.S. Probiotic Guide.


You’ll also want to understand the recommended dosage, which is usually presented as CFU (colony forming units). The U.S. Probiotic Guide also provides guidance on doses that may provide benefit specific to various brands. More isn’t always necessary or better. When scoping out various brands of probiotics, it is also important to look for the guaranteed CFU at the end of shelf life (or the product’s expiration). For products that only guarantee the CFU at the time of its creation, recognize that by the time you take it, the product’s potency will have diminished.

Administration and Storage

Not all probiotics require refrigeration, but you should be aware of proper storage conditions so the product does not deteriorate prematurely. Also consider how the product should be taken. Enteric coated or time-released tablets or capsules may be the best avenue for getting the probiotic safely to the intestine through the acidic stomach.

What to Buy

Dietary supplements are regulated differently than food and drugs so it is advantageous to obtain supplements from a brand that has undergone third-party testing. A seal from NSF or USP Verified can help guide you to reliable brands and decrease your risk of taking something that may be contaminated with ingredients that shouldn’t be in the product.

Feed the Microbes

Prebiotics are foods that feed the microbes that live inside the gut. Fibers that are poorly absorbed as well as polyphenol-rich foods feed the gut bacteria. Prebiotic foods include garlic, onions, sunchokes, beans and nuts, and chicory root (or inulin) which is added to many products such as granola bars. Wine, coffee, and berries, which contain a high concentration of polyphenols, also feed healthy gut microbes.

Prebiotics are important to feed gut bacteria but they’re highly fermentable and may cause further GI distress such as gas and pain. Fiber is helpful, but not all fiber is equal. When adding fiber-ful foods to the diet, allow the body to adjust to an incremental amount of fiber and ensure you drink adequate water. If you have normal bowel movements and are not gassy or bloated, great. If you react adversely, scale back on the amount of fiber you’re consuming and build your tolerance slowly. For many, it’s simply knowing your threshold.

Manage Your Expectations

The microbiome (the microorganisms in the gut) of each person is different. If a probiotic supplement works for one person, it may not work for you. There are various factors that can impact your gut microbiome and if and how it reacts (or doesn’t react) to various probiotics. It may take a few months to notice any difference and you may feel worse initially before feeling better.

If you don’t suffer from GI issues, a probiotic supplement may not be needed. Instead, feed your body and your gut with probiotic- and prebiotic-containing foods as part of an overall healthful diet. Although it isn’t likely that a probiotic supplement will be harmful, it might just be a waste of money. As with any supplement, you should always consult with your physician before taking it.


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