The scientists discovered that the probiotics successfully colonized the GI tracts of some people, called the "persisters," while the gut microbiomes of "resisters" expelled them. Moreover, the persister and resister patterns would determine whether probiotics, in a given person, would impact their indigenous microbiome and human gene expression. The researchers could predict whether a person would be a persister or resister just by examining their baseline microbiome and gut gene expression profile.
Kefir: This could be the most ideal probiotic dairy product because it contains both bacteria and yeast working together to provide the numerous health benefits. In a recent eight-week study, people with diabetes were given kefir milk containing Lactobacillus casei, Lactobacillus acidophilus, and bifidobacteria vs. conventional fermented milk. The hemoglobin A1C levels were significantly lower in the group consuming the kefir.
That said, supplements with higher numbers of CFUs are sometimes used to treat conditions such as irritable bowel syndrome (IBS), allergies, and respiratory illness. While probiotics have generally been found to be safe for most people with normal immune systems, too much can cause gas and upset stomach. We narrowed our search to supplements with dosages between 1 billion and 100 billion CFUs. 

Uncontrolled changes in blood sugar levels or a decreased ability to regulate insulin can have serious effects on your overall health, and since far more men than women are at risk for these changes, these issues are well worth paying attention to.5 Research indicates that regularly taking probiotic supplements containing Lactobacillus and Bifidobacterium can help your body maintain blood sugar levels already within a normal range, whether you're simply at risk for insulin-related challenges or you're already experiencing them.
The concept of probiotics is credited to Élie Metchnikoff, a Russian scientist born in the mid-1800s, whose work provided profound insights into immunology and microbes. He developed a theory about aging that over the years had been forgotten in mainstream medicine but is now embraced by many scientists: namely, that health is influenced by toxic bacteria in the gastrointestinal (GI) tract. He is said to have noticed that people who lived to be over 100 years old in the Balkan States and Russia drank sour milk, which we now call yogurt or kefir, every day. In fact, Bulgarian yogurt cultures even today are regarded as highly therapeutic.
Here’s a startling fact: For every one human cell we have, there are ten bacteria cells in our body to match it. That means that the majority of DNA in our body isn’t even human; it’s from the 500 bacteria species that call us home.1 Thinking about that much bacteria might have your skin crawling, but the relationship between human and bacteria is really a perfect synergy: we give bacteria room and board, and in return, they work hard to protect our intestinal health, which ultimately protects the health of our immune system and overall well-being. But if we have that much bacteria already living in our gut, you might be thinking to yourself, what are probiotics’ benefits?
Whether a brand of probiotics works really depends on its quality and your body's own gut. Everyone has a different set of gut flora so try several to see what works for you. Using a brand of at least 40 billion CFU is best. There seems to be some debate as to whether one should use refrigerated or unrefrigerated probiotics. I went with the side that claims unrefrigerated are sturdier and less prone to die off.

The root of the word probiotic comes from the Greek word pro, meaning "promoting," and biotic, meaning "life." The discovery of probiotics came about in the early 20th century, when Elie Metchnikoff, known as the "father of probiotics," had observed that rural dwellers in Bulgaria lived to very old ages despite extreme poverty and harsh climate. He theorized that health could be enhanced and senility delayed by manipulating the intestinal microbiome with host-friendly bacteria found in sour milk. Since then, research has continued to support his findings along with suggesting even more benefits.

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Survival past stomach acids - probiotic powder in capsule form is ill prepared when it comes to protecting the delicate bacteria from being pulverized by the harsh environment of the stomach acids. Worse, most of the organisms tend to die off before they reach their intended destination due to moisture that gets trapped between the capsule shell and the powder.
On my recent trip to Japan, one thing I noticed was the inclusion of pickled vegetables in almost every traditional Japanese meal. Unfortunately, many Americans don’t consume enough of these probiotic-rich foods and drinks. Even when they do, restoring equilibrium oftentimes requires therapeutic doses of these microorganisms, because most everyone has been on several rounds of antimicrobials. That’s where a probiotic supplement comes in.
Disclaimer: No content contained in this website is intended as, or should be construed as, medical advice. Consumers should consult with their physician for individual medical recommendations. The information in this website concerns Dietary Supplements. They are not drugs. Our Dietary Supplements are not intended to diagnose, treat, cure, or prevent any disease. Renew Life does not receive compensation for studies referenced in articles on this site; products mentioned in the same article should not be considered an endorsement by the author of the study.

Suez and colleagues investigated the recovery of the gut microbiota after antibiotic treatment and found that probiotics might perturb rather than aid this process. The probiotics rapidly colonised the gut but prevented the normal microbiota from repopulating for up to 5 months. While likely to be considerably less appealing, the group who received autologous faecal microbiota transplantation recovered their microbiota the quickest, with the composition of the microbiota returning to normal within days. Furthermore, Zmora and colleagues showed that colonisation occurred in highly individualised patterns, with some people's gastrointestinal tracts rejecting probiotics and others allowing colonisation by the probiotic strain, meaning that many individuals taking probiotic supplements are simply wasting their money.

One thing that is often overlooked is gut health and the benefits of probiotics for weight loss. Gut microbiota can affect food intake choices, appetite, and body weight and composition. Dysbiosis, an imbalance in the gut microbiota with a shift favoring pathogens and opportunists, is common in overweight people. The pathogens and opportunists create an inflammatory situation that affects insulin and other hormones, resulting in the inability to lose weight.
As a world-renowned neurologist and nutritionist, Dr. David Perlmutter has become somewhat of a household name when it comes to the linkage between what we eat and how we feel. He is known as “The Empowering Neurologist” and has been featured on the Doctor Oz Show, CNN, and NPR as well as in prominent publications like The New York Times, Forbes, Time Magazine, and the Wall Street Journal. If that wasn’t enough to spark your interest, Dr. Perlmutter is also the award-winning author of the Grain Brain Whole Life Plan, Brain Maker, and Grain Brain, all of which have become international bestsellers.
We also found strains linked to five other health benefits like weight loss and lowering cholesterol. We feature options for those cases below, but they aren’t top picks because those use cases aren’t as heavily researched as immune health or IBS relief. Still, chances are any probiotic supplement is going to make some improvement to your digestive health, so don’t be afraid to experiment.

“Highly recommend –There are quite a few probiotics manufactured specifically for women. Some are decent while others are not so good. For me, I require one on a daily basis to maintain my feminine health. When I try a new probiotic that is made specifically for women, it makes me a bit nervous because I will end up with yeast or bladder infection if it is not effective. With AZO, I am happy to report it is a great probiotic and highly recommend it to all women! It works great.” – Vicki
CFU: This is the number of "colony forming units" present in each dose, which are measured in the billions. And while more isn't always better, "you want at least 20 to 50 billion CFU," says Dr. Nazareth. Just for reference, a very high dose is 400 CFU, which most experts agree is not necessary unless your health care practitioner specifically recommends this for you. It's also important to check for the guaranteed CFU upon expiration, which should be listed clearly. "Some products only guarantee the CFU number at the time of manufacturing, therefore will be less potent by the time the product reaches your home," she says.
Certain brands, like Attune (attunefoods.com; available at Whole Foods), have pumped up the dessert by adding probiotics. (Attune boasts 6.1 billion CFUs, or "colony forming units," a measure of live, active microorganisms per serving. As a comparison, some probiotic supplements may contain 1 to 50+ billion CFUs.) Sounds crazy, but it's backed by science. One study in the International Journal of Food Microbiology found that probiotics added to chocolate were able to reach the GI tract where they could get to work colonizing the gut with healthy bacteria.
The bottom line: Stick to trusted whole food sources of probiotics if you don’t know a probiotic supplement brand you trust. “Kimchi, pickled beets, Greek yogurt and sauerkraut are great sources of probiotics. If you don’t like them, throw them into a food you do like, like a smoothie, and add your favorite fruit to help mask the flavor,” Taub-Dix says.

If you get sick often, probiotics might be the immune booster you've been looking for. The Cleveland Clinic says they've been shown to strengthen immunity by enriching and replenishing the good bacteria in the body. And when you eat foods with probiotics regularly, it's easier for your body to produce vitamins and enzymes that help keep your intestines happy.

Quick note about some formulations with multiple strains (including this one): Take a look at the label below and you’ll see that the supplement contains a mix of strains, but the label just says there is a total of 20 billion CFUs (how they measure the amount of bacteria). This does not tell us how much of each particular strain there is, and we want to know that there are at least 1 billion CFUs per strain to get a beneficial effect.


Fermenting a cucumber into a pickle amps up a cuke's powers, infusing the crunchy veggie with probiotics. Like sauerkraut, not all pickles offer the good bacteria, though. Look for those made with brine (salt and water) rather than vinegar. These brands will list "live cultures" on the label (like Bubbies). You can also use water, salt, and spices to naturally culture pickles and other veggies—like beets, green beans, and carrots—at home with delicious results. One warning: remember that pickles are salty—one dill can easily offer up more than 10% of your sodium needs in a day.
Eating foods rich in good bacteria and using probiotic supplements may help provide protection from inflammatory bowel diseases, including ulcerative colitis and Crohn’s disease. The evidence is stronger, however, for an improvement in ulcerative colitis, while Crohn’s disease may not benefit as greatly. In addition, there is ongoing research studying the role of probiotics in gluten issues, including celiac disease.
As with other types of supplements, scientists are still discovering the full potential of probiotics. However, when taken regularly, it is believed that they help support digestive health by helping maintain the balance of beneficial and non-beneficial bacteria in your digestive tract. Having a natural balance of good bacteria in the digestive tract can help defend against occasional digestive issues. In addition, probiotics play an important role in supporting immune health, since 70% of the body's immune system is found in the digestive tract.∗
One overlooked mechanism that supports your innate immunity is gut health, specifically the role probiotics play. Good probiotics benefit your health by keeping your gut microbiota, inflammation, and immune system balanced preventively, as well as acutely when you are sick, so that no matter which flu strain comes along, your immune system is ready.
Notably, after someone was tagged a “persister” or “resister” clear patterns emerged on how probiotics would impact his or her indigenous microbiome and gut bacteria profile. "Although all of our probiotic-consuming volunteers showed probiotics in their stool, only some of them showed them in their gut, which is where they need to be," Eran Segal said in a statement. "If some people resist and only some people permit them, the benefits of the standard probiotics we all take can't be as universal as we once thought. These results highlight the role of the gut microbiome in driving very specific clinical differences between people."
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