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.

That’s why adding probiotics and prebiotics to your diet provide the best possible outcome from a bacterial perspective. It isn’t always easy to eat naturally prebiotic-enriched foods, however, because they are often distasteful to eat in quantity. Would you enjoy eating several cups of raw onion or garlic every day? Probably not. Other foods that contain prebiotic fiber, such as bread and bananas, are high in calories. Consuming hundreds of calories of these foods every day is counterproductive if you’re trying to lose weight.
The National Center for Complementary and Integrative Health (NCCIH) calls probiotics “live microorganisms (in most cases, bacteria) that are similar to beneficial microorganisms found in the human gut.” The NCCIH makes the point that we often think of bacteria as harmful “germs” — however, probiotic bacteria actually helps the body function properly.
We started our search with the most popular products from major supplement retailers like Amazon, Drugstore.com, GNC, and Whole Foods. That gave us over 200 supplements. With so many options, we then narrowed our search to 70 probiotics whose purity, potency, and projected efficacy have been vetted by an independent lab like ConsumerLab, Labdoor or the National Science Foundation (NSF). Those labs test — among other things — supplements’ actual composition against labels, verifying ingredient lists are truthful and that contaminants aren’t present. Because supplement claims aren’t regulated by the Food and Drug Administration (FDA), we wanted to make sure someone was testing whether they worked as described.
But before you start reaching for the calcium supplements, there may be a more effective way to support your bone health. Like many other parts of the body, the health of your bones is closely tied to the health of your gut, especially your intestines. Temporary intestinal inflammation can trigger an immune response in which your body releases interleukins, proteins that have an immune function but also absorb bone tissue. If the temporary inflammation remains unaddressed, these molecules can take a toll on your bones, eventually weakening them.14
A slightly more surprising result, however, seems to be the way that probiotics may impact some of the symptoms of autism. Autism and gut health have been discussed for some time, as patients with the disorder typically suffer from a large number of digestive issues. However, based on animal studies, it seems possible that altering the quality of gut bacteria might benefit not only the digestive system, but the abnormal behaviors in autism, too. In 2016, a case study of a boy with severe autism was reported. While being treated with probiotics for digestive problems, the patient spontaneously improved on the ADOS scale, a diagnostic rating system for people with autism. The score dropped from 20 down three points to a stable 17, and according to the report, ADOS scores do not “fluctuate spontaneously along time” and are “absolutely stable.”
Additionally, it's a good idea to take note of the number of colony-forming units (CFUs) that are in the supplement you're considering, Angelone says. CFU count tells you the number of viable, active bacteria present in a tablet, she explains, and one billion (yes, seriously) is a typical dose. However, if you're struggling with a specific health condition, you may need more than that, Warren says. Your doctor can help you decide whether that's the case and may be able to steer you toward a good supplement to get you started. Here are a few to consider if you decide that probiotics are right for you.
Lebwohl says IBS isn’t just about intestinal distress. For many IBS sufferers, it’s about the way our brain receives messages about pain. He describes the human colon as “almost reptilian” in the way that it contracts and relaxes throughout the day, but says these contractions are usually happening way below our threshold of consciousness, so we don’t even notice. In people with IBS, the neurotransmitters in our gut (yes, we have them in there too) may be sending severe distress signals to the brain about benign contractions happening in digestive tract.

Many studies have been conducted about the benefits of probiotics on a large number of health issues and conditions. Here, I’ll focus on the more thoroughly researched probiotics benefits, largely by sharing the results and data of meta-analyses on the subjects. Then, I have listed several areas of emerging research on the benefits of probiotics, reflected in small or pilot studies with promising results on probiotic benefits, as well as ways probiotics can be accessed.

Bottom line: Probiotics are a promising field of research and may one day be used to treat or help prevent many disorders. But there’s not enough solid evidence to recommend their widespread use. Vague claims that probiotics "support good digestive health" are meaningless. Larger, longer and better studies are needed to test specific strains for specific conditions and to determine the proper doses and regimens.
The best probiotic manufacturers will list their potency (in CFUs) at the time of expiration, ensuring you get the dosage you’re paying for. Dr. David Perlmutter, board-certified neurologist, American College of Nutrition Fellow, and author of The New York Times bestsellers "Brain Maker" and "Grain Brain" puts it this way: “Avoid products that indicate a specific number of bacteria ‘at the time of manufacture,’ and instead look for products that, like other supplements, have a shelf life.” Each of our top picks clearly shows a specific “best by” or “expires on” date on its bottle.
"People have thrown a lot of support to probiotics, even though the literature underlying our understanding of them is very controversial; we wanted to determine whether probiotics such as the ones you buy in the supermarket do colonize the gastrointestinal tract like they're supposed to, and then whether these probiotics are having any impact on the human host," Eran Elinav said in a statement. "Surprisingly, we saw that many healthy volunteers were actually resistant in that the probiotics couldn't colonize their GI tracts. This suggests that probiotics should not be universally given as a 'one-size-fits-all' supplement. Instead, they could be tailored to the needs of each individual."
After suffering from liquid nighttime but painless diarrhea for over a year (which I semi-controlled with one Imodium/day), I had a colonoscopy that gave a diagnosis of microcolitis. After the colonoscopy, I developed for the first time excrutiatingly painful gas pain in the LLQ. Usually this pain started during aerobic activity such as walking, but not always. Sometimes I woke up with it. CT scan revealed nothing. Will a probiotic help and if so, which would be best? There are so many it is hard to choose.
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.
Consuming probiotics regularly will reduce the risk of this. "The concept is that if we have an unhealthy, unbalanced gut environment, toxins can be released into the bloodstream and cause inflammation throughout the body," Engelman adds. "This shift in gut flora and the subsequent inflammation can cause a flare-up in the skin of those who are predisposed to acne, eczema, or rosacea."

The National Center for Complementary and Integrative Health (NCCIH) calls probiotics “live microorganisms (in most cases, bacteria) that are similar to beneficial microorganisms found in the human gut.” The NCCIH makes the point that we often think of bacteria as harmful “germs” — however, probiotic bacteria actually helps the body function properly.
Oral health. An increasing number of probiotic lozenges and gums are promoted for oral health—to reduce periodontal disease, throat infections, and bad breath, for example. There’s preliminary evidence that certain strains may have some benefits, but commercial products may not have the same strains and formulations as those tested in published studies.
In the new study, the researchers analyzed information from 15 healthy volunteers who took either a probiotic product containing 11 strains of bacteria, or a placebo, for four weeks. The participants also underwent colonoscopies and upper endoscopies before they took the probiotics or the placebo, and again after the four-week treatment period. (An upper endoscopy looks at the upper part of the digestive tract.) During these procedures, the researchers took samples from inside participants' guts.
Possibly the most popular probiotic food is live cultured yogurt or greek yogurt made from the milk of cows, goats or sheep. Yogurt, in most cases, can rank at the top of probiotic foods if it comes from raw, grass-fed animals. The problem is there is a large variation on the quality of yogurts on the market today. When buying yogurt, look for three things: First, that it comes from goat’s, sheep milk or A2 cows milk; second, that it’s grass-fed; and third, that it’s organic.
Because chronic inflammation is at the root of many diseases and health conditions, the fact that probiotics exert this effect in the gut, where 80 percent of the immune system lies, is crucial. The immune-boosting benefits of probiotics seem to be particularly helpful for the quality of life of seniors. Currently, research is underway to test whether probiotics can “reduce inflammation and improve gut immune health in HIV-positive individuals” who haven’t yet undergone treatment.

Uh, no. “There have been studies that suggest a theoretical link between the microbiome and even changing the microbiome, and changes in the brain,” Lebwohl tells me. He specifically points to this study, in which healthy women with no gastrointestinal issues had their brains imaged before and after a month of consuming yogurt products containing probiotics twice daily.

Many wondered whether probiotics could be therapeutic in other gastrointestinal disorders. Unfortunately, that doesn’t appear to be the case. Probiotics didn’t show a significant benefit for chronic diarrhea. Three reviews looked at how probiotics might improve Crohn’s disease, and none could find sufficient evidence to recommend their use. Four more reviews looked at ulcerative colitis, and similarly declared that we don’t have the data to show that they work. The same was true for the treatment of liver disease.
To factor strain-specific benefits into our efficacy score, we referenced the information in these guides. Products were rewarded for containing strains on these lists. Additionally, measured levels of each strain were compared to what is thought to be effective based on these guides, and scores were scaled accordingly. In cases where products did not list strain-specific amounts, or their listed strains were not included in these guides, total measured CFUs were compared to a general effectiveness threshold of 1 billion CFUs cited by research published in the American Journal of Clinical Nutrition11.
Cleaning up your diet to remove things that bother you and to add nutrients you and your microbiota need, physical activity to reduce stress and increase feel-good neurotransmitters, mindfulness to discover how your thoughts affect your feelings, and daily consumption of probiotic pills and foods are easy ways to improve your mental health outlook.