What's more, there's still a lot more to learn about the microbiome and probiotics, in general. "Truth be told, the research area of probiotics and health is still pretty much in its infancy," says registered dietitian Kate Scarlata. Research is growing in the area of gut microbiome daily—but it is much more complicated than first thought." With all these options and major gaps in the available information, where are you supposed to start? Here, gut experts narrow it down to three simple tips for picking the right probiotic for you.
"Probiotics applied topically sit on the skin's surface and prevent the skin cells from seeing the bad bacteria and parasites that can cause this immune system response," confirms Engelman. "This is known as 'bacterial interference,' as probiotics protect the skin and interfere with the ability of bad bugs like bacteria and parasites to provoke an immune reaction.
The right resident strains - quite a few probiotics on the market contain things like active yeasts or soil based organisms. While these ingredients may be helpful to some, if you want to optimize your gut health, you need to look for strains that are resident to the human gut like those from the Lactobacillus, Bifidobacterium, and Streptococcus families.

Several large-scale studies and two meta-analyses have confirmed that probiotics should be a major consideration in determining natural remedies for diabetes. In a massive study involving almost 200,000 subjects and a total of 15,156 cases of type 2 diabetes, researchers confirmed that a higher intake of probiotic-rich yogurt reduced the risk of developing diabetes.
While one 2009 study did show some evidence for reducing cold and flu symptoms in children ages three to five and a 2015 analysis showed probiotics to be better than placebo in preventing acute upper respiratory infections, neither were enough to convince the National Institutes of Health of the efficacy of probiotics for colds and flu. The NIH confirms, “the evidence is weak and the results have limitations.”
Some foods are made by adding bacteria — yogurt, pickles, cottage cheese, kombucha, and sauerkraut are good examples. Those foods work to provide the same probiotic benefits as supplements. However, most foods are so processed and pasteurized that it’s unlikely you’ll see the same benefits, let alone the right strains, as you would with a supplement. Regardless, it can’t hurt to get extra probiotics through your diet.
Every person's microbiome is different, which means what worked for others might not work for you. "What you eat, whether you were born by C-section or vaginally, what antibiotics you have been exposed to, and whether or not you have ever developed food-borne illness are just some of the many factors that impact your gut microbiome," explains Scarlata. And while research can help you determine which strains to take at which dosages, there may still be several different formulations to choose from.
A 2014 review by Cochrane—an independent network of experts who serve as rigorous arbiters of medical research—found that probiotics may be particularly useful in a hospital's neonatal intensive care unit. The addition of beneficial bacteria to a nutritional regimen seems to significantly reduce the likelihood of developing necrotizing enterocolitis, which is a devastating, poorly understood and often fatal gut disease that primarily afflicts preterm infants—especially the smallest and most premature among them. Researchers think that many cases of the disease begin with an opportunistic bacterial infection in the not yet fully developed intestine of an infant. As the illness progresses, gut tissue becomes increasingly inflamed and often starts to die, which can, in turn, rupture the intestine and flood the abdominal cavity with pathogenic microbes that proliferate to dangerous levels. Researchers estimate that 12 percent of preterm infants weighing less than 3.3 pounds will develop necrotizing enterocolitis and that 30 percent of them will not survive. Standard treatment involves a combination of antibiotics, feeding via intravenous tubes, and surgery to remove diseased and dead tissue. Probiotics probably prevent the disorder by boosting the numbers of beneficial bacteria, which may deter the harmful ones.
This Korean staple relies on lactic acid fermentation (also called lacto-fermentation) to turn cabbage or other vegetables into a spicy, pungent side dish that's packed with vitamin C. Order it at Korean restaurants or buy it in the refrigerated section of your grocery store (King's Kimchi is widely available at Walmart). For some guidance on making your own, turn to The Art of Fermentation ($23; amazon.com). Then, use it to spike veggie-laden rice bowls, top on soup, or serve alongside meat.
Another study by Elinav and his colleagues suggests that not everyone’s gut reacts the same way to probiotic pills. They studied samples of microbiomes from antibiotic users before and after they took supplements for four weeks. The good bacteria were found in the digestive tracts of some people. But in others, the bacteria were present only in stool samples, not in their digestive tracts, where they’re thought to be needed to improve health.
Probiotics have also been researched for how they support the immune system. Studies suggest that probiotics can improve how the immune system functions such as by decreasing upper respiratory tract infections in adults and reducing the need for antibiotics. Studies in children show that a regular diet including probiotics reduces colds and flu-like symptoms and improves attendance in preschool and day care settings.
Probiotic supplements and foods can play a major positive role in brain fog. Lactobacillus, in particular, can produce neurotransmitters used for brain neuron-to-neuron transmission to facilitate thinking. Probiotics can interact with the vagus nerve to the brain, with the enteric nervous system that can communicate with the brain, and with the brain via chemical messengers.

The right resident strains - quite a few probiotics on the market contain things like active yeasts or soil based organisms. While these ingredients may be helpful to some, if you want to optimize your gut health, you need to look for strains that are resident to the human gut like those from the Lactobacillus, Bifidobacterium, and Streptococcus families.

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.
The two main species you want to look for are: Lactobacillus and Bifidobacterium. Within these two species, there are a lot of different strains. The strains we chose for our probiotic—Lactobacillus acidophilus, Lactobacillus plantarum, and Bifidobacterium longum—have been shown to help modulate the immune system, help with autoimmunity conditions (which affect most of my patients), and counter infections in the gut.

Step No. 1 is consume more sour foods — it’s the top way probiotics benefits can be accessed. Embrace what I call “the power of sour” with sour foods like apple cider vinegar and fermented vegetables. They contain some probiotics, but also they contain certain types of acids like gluconic acid and acetic acid, healthy acids that support the function of probiotics (even functioning like prebiotics in some cases).

Don't assume that the only way you can get your probiotic yogurt fix is through dairy. Cultured soymilk, or soy yogurt, is a non-dairy alternative that also boasts live active cultures. Most of these products are fortified with calcium and vitamin D to make them comparable to dairy yogurts. It makes a great option if you're vegan or lactose intolerant. (And if you're looking for more variety, almond milk and coconut milk yogurts are also rich in probiotics.)
From Lactobacillus acidophilus to Bacillus Coagulans, the BlueBiotics blend is a veritable list of the most researched and proven probiotic bacteria known to science. And recent advances on the blend have made it the only full-spectrum probiotic supplement on the market, as it contains strains which are typically not available to the general public (Bacillus Coagulans and S. boulardii). The CFU count alone is remarkable enough, leaving most comparable spectrums in the dust… HOWEVER even more surprisingly our tests showed that a whopping 98% of the probiotic colonies in BlueBiotics were still alive, making this BY FAR the most effective probiotic supplement that we have ever reviewed. Also, because of the diverse pool of strains in BlueBiotics, users have reported a wide variety of benefits from weight loss, to increased energy, improved digestive health and cognitive function. Many of our staff switched to these probiotics, as well as myself and my family.
The U.S. Clinical Guide to Probiotic Products1, Canadian Guide to Probiotic Supplements2 and the WGO Global Guidelines for Probiotics and Prebiotics3 provide suggested effective amounts of specific strains for treating certain health conditions, such as constipation or IBS. All 37 products listed the species of bacteria they contained, but only 14 listed amounts of individual strains. We found that 9 of those 14 products provided beneficial bacteria at effective levels. The Center for Responsible Nutrition recommends4 the industry move toward specifying strains as a best-practice because whether a product works and for what purpose depends on its strains.
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."
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.
The bad news about constipation is that there can be many causes, from simple causes like dehydration and lack of fiber to complicated structural causes or disease. While constipation may seem to be only a nuisance that causes uncomfortable symptoms such as abdominal bloating or pain, the truth is that constipation increases the risks of several diseases.
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
Digestive tract conditions. Probiotic supplements may be useful in treating and preventing inflammatory conditions, such as pouchitis (which affects people who have their colons removed), inflammatory bowel diseases (such as ulcerative colitis and Crohn's disease), and chronic stomach inflammation and ulcers caused by Helicobacter pylori bacterium. They may also be helpful in treating constipation, irritable bowel syndrome, acid reflux, spastic colon; shortening the duration of infectious diarrhea; and reducing the recurrence of bladder and colorectal cancer. Some studies suggest that yogurt is helpful in preventing diarrhea - a common side effect of treatment with antibiotics. It has also been shown to prevent or treat urinary tract infections and vaginal yeast infections in women.
Taking a probiotic every day is a good way to help prevent getting sick and having to go on antibiotics in the first place. Preventative measures, of course, are preferred. Another that is believed to help is upping your vitamin D intake when your immune system needs a boost. Diet is also huge in terms of preventing sickness. Studies show that you can change your microbiome within hours of adjusting your diet. If you’re not into sauerkraut, even just cutting back on sugar and eating more whole foods can make a difference.
Flu is short for influenza, an upper respiratory viral infection. The main problem for you, and the main advantage for the survival of influenza viruses, is that there are many variations that can cause illness. Flu shots are based on virus strains that are anticipated to be widespread. Sometimes those assumptions are correct and other times they are not. This section will show you one overlooked way to fortify your body to best avoid becoming sick with the flu at all, or how to recover if you do succumb.
Better Health Review ranks Ultimate Flora as the most effective probiotic supplement. It contains 30 billion active bifidobacteria for colon health, and 20 billion lactobacilli and lactococcus cultures for the small intestine. According to Better Health Review, it contains all natural ingredients. It earns a perfect 5 score from Better Health Review, and the magazine “Vitamin Retailer” voted it best two years in a row.