Research suggests probiotics work better as a team. Even pairs are more effective than individuals. Take the strains Lactobacillus Acidophilus and Bifidobacterium Bifidum BB-12, for example. When combined, this duo-force has been shown to help treat GI-specific ailments. In fact, one survey found 75 percent of studies that compared the effect of a strain mixture with a single-strain supplement showed a mixture was more effective at improving irritable bowel symptoms, immune function, and digestive health.
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.∗
“If someone has disrupted his gut microbial balance, this is where a probiotic can be of benefit,” says Gail Cresci, PhD, RD, an intestinal microbe specialist with Cleveland Clinic’s Department of Gastroenterology, Hepatology and Nutrition. “But whether it’s really going to help and whether you’re taking the right one are the big questions out there.”
The second piece of research investigated whether patients should take probiotics to help the recovery of the natural gut bacteria after treatment with antibiotics. The evidence supporting this is not entirely clear and the FDA does not officially recommend it, but there are some reputable sources which discuss their use, such as this blog from Harvard Medical School. Research has suggested that up to 60% of healthcare professionals in the U.S. recommend taking probiotics, but is this justified and could it even be harmful?

Unlike MegaFood, the Renew Life label’s cold-storage recommendation is printed so small we nearly missed it (and it didn’t ship with a cold pack). If a probiotic requires refrigeration, be vigilant when buying it — the retailer that stores it or the company that ships it should keep it refrigerated until it gets to you. Otherwise, some of its potency might diminish in storage or transit.


Sure, why the hell not? Lebwohl says: "Essentially a yeast infection is an overgrowth of a kind of fungus. In theory, a probiotic could potentially have an effect of the microbiome of the vagina, though proof of its effectiveness hasn’t really been established.” No harm in giving it a try as long as you don't succumb to the temptation to put yogurt in your vagina.
Like some of the other probiotics we’ve reviewed, the HyperBiotics PRO-Women Probiotics with Cranberry Extract and D-Mannose do not need to be refrigerated in between uses. What sets this particular formula apart though is its longer shelf life made possible by the patented HyperBiotics ‘LiveBac’ manufacturing process. In fact, the HyperBiotics PRO-Women Probiotics formula can usually last for more than a year when stored in normal indoor conditions!

Other uses. Many other claims are made for probiotics—that they lower cholesterol, alleviate allergic skin conditions (like eczema), treat ulcers and urinary tract infections, improve vaginal health, reduce the risk of colon cancer, ease anxiety and depression, and ward off traveler’s diarrhea. Good evidence to support these claims is lacking. Research on probiotics for weight loss has yielded inconsistent results, and even studies with positive results have mostly found very small benefits, as was seen in an analysis of 15 clinical trials in Obesity Reviews in 2018.

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 can be found in some foods, such as yogurt and cheese, as well as dietary supplements. There are numerous probiotic supplements on the market that contain a variety of bacteria. The two most common types of bacteria found in probiotics belong to the groups known as Lactobacillus and Bifidobacterium. Phillips'® Colon Health® Probiotic Capsules contain 3 types of good bacteria, from both groups, to help defend against occasional constipation, diarrhea, gas and bloating.∗
Notions don’t equal evidence though, and Lebwohl cautioned against thinking of probiotics as a cure-all, and examining the ways in which they’ve been proven to work as well as the ways in which they really haven’t. So which medical conditions have probiotics actually shown promise in treating and which claims have the credibility of a used car salesman on acid?
Similar to yogurt, this fermented dairy product is a unique combination of milk and fermented kefir grains. Kefir has been consumed for well over 3,000 years, and the term kefir was started in Russia and Turkey and means “feeling good.” It is created by the fermentation of milk by the bacteria, and yeasts in kefir starter break down lactose in the milk — that’s why kefir may be suitable for those who are otherwise lactose-intolerant.

We’ll start with the headliner: the BIO-tract peral, which packs the equivalent of 75 billion CFUs into one tiny, filler-free, 5-billion CFUs pearl. The trick is in protecting those 5 billion CFUs over an 8 to 10-hour period, so they bypass your acidic stomach and reach your intestinal tract, alive and well, allowing you to experience the full and multitudinous benefits of plentiful and beneficial gut bacteria.
Yogurt: It can contain Streptococcus thermophilus, Lactobacillus bulgaricus, L. acidophilus, and Bifidobacterium bifidum. Research has shown links with yogurt to have positive effects on the gut microbiota and is associated with a reduced risk for gastrointestinal disease and improvement of lactose intolerance (especially among children), type 2 diabetes, cardiovascular disease, allergies and respiratory diseases, as well as improved dental and bone health.

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.
Overall, Align Probiotic is one of the better “daily” probiotics out there.  It’s easy to take, comes in convenient packaging and doesn’t require refrigeration.  And it has some research showing it helps with gas, bloating and constipation, especially in women with IBS.  Lots of things to like about this probiotic!  Read the full review here… or click here to go buy it now!
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.
In the first study, 25 human volunteers underwent upper endoscopies and colonoscopies to sample their baseline microbiome in regions of the gut. 15 of those volunteers were then divided into two groups. The first group consumed generic probiotic strains, while the second was administered a placebo. Both groups then underwent a second round of upper endoscopies and colonoscopies to assess their internal response before being followed for another 2 months.
The National Yogurt Association, who created this seal of approval, requires all yogurt manufacturers to include it on products that meet the standard of having a sufficient number of probiotics. The probiotics in store-bought yogurt need to meet this standard in order to be shelf-stable and reach your body alive. But even then, this standard isn’t all that useful in practice. The number just refers to the total number of live cultures and not the levels for each of those microbes. It’s possible, Taub-Dix says, that a product won’t have high enough levels of a certain probiotic to have any effect.
While Lebwohl isn't comfortable endorsing a specific brand publicly, he did say "a widely used brand in which the compound is bifidobacteria or lactobaccilus seems like a reasonable way to go in a patient who is eager to give this a try, but would be best done under the supervision of a healthcare professional.” He does advise looking for a supplement with between 1 billion and 10 billion colony-forming units, or CFUs.
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.
If that’s the case, I recommend steering clear. They either don’t want you to know that they’re using a poorly-researched strain of probiotics or they’re simply ignorant to the fact that the strain of probiotic really matters and determines the benefit that you’ll receive as the consumer. I usually want to give these companies the benefit of the doubt, but honestly, if you’re making a probiotic supplement you should know this stuff is important.
According to the NIH, probiotic supplements contain many microorganisms that are the same as or similar to the ones that naturally live in your body, but there's still a lot of research to be done on probiotics and how they work. It's important to keep in mind that not all probiotics have the same effects and that taking probiotics isn't a guarantee of better health. And while they're generally safe for healthy people to take, with side effects being limited to mild digestive discomfort, they could interact with certain medications or pose health risks to people with underlying medical problems — that's why it's smart to talk to your doctor before getting started with a supplement.
Yes. Probiotics are incredibly important and effective. We know there are more bacteria in us and on us than our own human cells. The body is almost like a puppet—it is bacteria that really runs the show: They turn on enzymes, turn off genes, and dictate much of our health. We need them to break down nutrients, like copper and magnesium, so we can better absorb them. Interestingly, studies show that conditions like anxiety, depression, and weight gain can be transferred via fecal transplants (with mice), suggesting the broad impact bacteria has on health.
Probiotics are found in everything from chocolate and pickles to hand lotion and baby formula, and millions of people buy probiotic supplements to boost digestive health. But new research suggests they might not be as effective as we think. Through a series of experiments looking inside the human gut, researchers show that many people's digestive tracts prevent standard probiotics from successfully colonizing them. Furthermore, taking probiotics to counterbalance antibiotics could delay the return of normal gut bacteria and gut gene expression to their naïve state. The research publishes as two back-to-back papers on September 6 in the journal Cell.
The beneficial microbes, including probiotics, live with other microbes that are either benign, pathogenic (disease-causing), or opportunistic, meaning that they normally play nicely but can get out of control if given the opportunity. Actually, any microbe can cause you problems if it ends up in a place other than where it is supposed to be. Such a scenario can happen with intestinal permeability, commonly called leaky gut. Leaky gut happens when the layer of skin-like cells in your GI tract develops gaps in between the cells, allowing food particles, toxins, microbes, and other hazards to enter your bloodstream, if not stopped by the immune system. Since mucus, the thin layer of cells, and your immune system are your only defenses against the outside world within your digestive tract, it is very beneficial to you to have helpful microbes protecting you from potentially pathogenic microbes. These beneficial microbes can produce acids or antimicrobial products called bacteriocins, which hinder or kill pathogens. They can also stand in solidarity to prevent pathogens from taking up residence, or displace them if they do.
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.
Cardiovascular health is a major concern for men in Western societies. While some of the main challenges to maintaining a healthy heart (like excessive drinking and smoking) aren’t nearly as widespread as they once were, unwanted changes in heart function are still one of the most common reasons for men to need emergency medical care.1 But taking probiotics can help you keep your heart firing on all cylinders, even as you age.
If you’re looking for a great probiotic you can take every day to target everything from gut to skin health, the Culturelle Daily Probiotic is our top choice. Each capsule has 10 billion active cultures of 100 percent Lactobacillus GG, a probiotic that helps curb gas, bloating, and upset stomach, and works to boost your immune system. Each capsule has the probiotic equivalent of 10 cups of yogurt and is dairy-free, sugar-free, and gluten-free. This container comes with 30 pills to be taken just once a day (most recommend taking it at night, especially when you’re just starting on probiotics).
According to the NIH, probiotic supplements contain many microorganisms that are the same as or similar to the ones that naturally live in your body, but there's still a lot of research to be done on probiotics and how they work. It's important to keep in mind that not all probiotics have the same effects and that taking probiotics isn't a guarantee of better health. And while they're generally safe for healthy people to take, with side effects being limited to mild digestive discomfort, they could interact with certain medications or pose health risks to people with underlying medical problems — that's why it's smart to talk to your doctor before getting started with a supplement.
If you’re most interested in taking a probiotic supplement for overall gut health, I suggest starting with 30 to 50 billion CFUs. Take probiotics on an empty stomach once or twice a day for at least three months. After that time, reassess and decide if the benefits warrant continuing a maintenance dose of the probiotic supplement. However, if you have SIBO, beware of starting a probiotic too soon after your treatment. In this case, it’s best to work with a health practitioner on which probiotic is right for each stage of the treatment.
Our gut is home to over 500 bacterial species. These “visitors” form a bioreactor, which facilitates digestion, provides nutrients, and helps form the immune system. Some important nutrients made by this bioreactor include several B vitamins, vitamin K, folate, and some short-chain fatty acids. Up to 10% of an individual’s daily energy needs can be derived from the byproducts of the good bacteria in your gut.
Probiotics can be found in some foods, such as yogurt and cheese, as well as dietary supplements. There are numerous probiotic supplements on the market that contain a variety of bacteria. The two most common types of bacteria found in probiotics belong to the groups known as Lactobacillus and Bifidobacterium. Phillips'® Colon Health® Probiotic Capsules contain 3 types of good bacteria, from both groups, to help defend against occasional constipation, diarrhea, gas and bloating.∗

A closer look at the science underlying microbe-based treatments, however, shows that most of the health claims for probiotics are pure hype. The majority of studies to date have failed to reveal any benefits in individuals who are already healthy. The bacteria seem to help only those people suffering from a few specific intestinal disorders. “There is no evidence to suggest that people with normal gastrointestinal tracts can benefit from taking probiotics,” says Matthew Ciorba, a gastroenterologist at Washington University in St. Louis. “If you're not in any distress, I would not recommend them.” Emma Allen-Vercoe, a microbiologist at the University of Guelph in Ontario, agrees. For the most part, she says, “the claims that are made are enormously inflated.”
Some digestive disease specialists are recommending probiotic supplements for disorders that frustrate conventional medicine, such as irritable bowel syndrome. Since the mid-1990s, clinical studies suggest that probiotic therapy can help treat several gastrointestinal ills, delay the development of allergies in children, and treat and prevent vaginal and urinary infections in women.
Though capsules are ideal for quick, convenient consumption, powdered products are a great choice for anyone who wants to mix their probiotics with shakes or smoothies. The Hyperbiotics Organic Prebiotic Powder is a totally taste-free prebiotic powder that has inulin, FOS, resistant starch, and dietary fiber to help keep your gut health in line. Unlike probiotics, prebiotics works to nourish and grow the bacteria that is already in your body. This supplement also has acacia fiber, which is said to help suppress appetite and reduce gas and bloating. You can take between one and three scoops of powder a day, depending on how much microbial support you’re looking for. Each container comes with 375 grams or roughly 54 servings, and it doesn’t need to be refrigerated.
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.
About 60 to 80 percent of our immune system lives in our gut. Imbalances in the gut’s microbiome (which is primarily made up of bacteria) lead to digestive issues, while many many other potential effects can be felt throughout the body—from feelings of fatigue to depression, thyroid dysfunction, autoimmunity, and a host of skin issues. Conditions like rosacea, psoriasis, eczema, and acne are really inflammatory conditions, and often a manifestation of something that is happening deeper within the body. When you fix the gut (which, depending on your health, might include getting rid of an infection like Candida, eating a clean diet, and taking a probiotic), skin issues often resolve as well.
“Microbiome” refers to the trillions of bacteria and microorganisms that live on and in our individual bodies. “There’s increased recognition of the various ways that the microbiome affects our health,” Lebwohl tells me. “And with that recognition comes the true observation that many bacteria are good for us. This goes against the old idea that bacteria equal germs, which equal harm. It turns out that many bacteria keep us healthy and probiotics could potentially support that notion.”
We’ll start with the headliner: the BIO-tract peral, which packs the equivalent of 75 billion CFUs into one tiny, filler-free, 5-billion CFUs pearl. The trick is in protecting those 5 billion CFUs over an 8 to 10-hour period, so they bypass your acidic stomach and reach your intestinal tract, alive and well, allowing you to experience the full and multitudinous benefits of plentiful and beneficial gut bacteria.
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.
Probiotics are bacteria that help keep the natural balance of organisms (microflora) in the intestines. The normal human digestive tract contains about 400 types of probiotic bacteria that reduce the growth of harmful bacteria and promote a healthy digestive system. The largest group of probiotic bacteria in the intestine is lactic acid bacteria, of which Lactobacillus acidophilus, found in yogurt with live cultures, is the best known. Yeast is also a probiotic substance. Probiotics are also available as natural health products.
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.
"Contrary to the current dogma that probiotics are harmless and benefit everyone, these results reveal a new potential adverse side effect of probiotic use with antibiotics that might even bring long-term consequences," Elinav says. "In contrast, replenishing the gut with one's own microbes is a personalized mother-nature-designed treatment that led to a full reversal of the antibiotics' effects."
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.
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.
Overall, Garden of Life Primal Defense Ultra is one of my favorite probiotics! It uses a wide variety of potent probiotic strains that may help with daily digestion and specific stomach ailments. So it’s very flexible as far as probiotics are concerned. After personally testing out the product, my overall health felt improved, I wasn’t bloated, and I was digesting my food much better than normal.  Read the full review here… or click here to go buy it now!
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.
Many Lactobacillus and Bifidobacterium species are naturals at protecting and improving gut health. Additionally, research in animals and humans has shown that probiotics decrease scores on depression assessments, thereby alleviating depression. As a matter of fact, there is a new term, psychobiotics, for these microbes that influence mental health conditions like depression.
However, these quality of life improvements are varied, and some improvements are quite mild. Sample group, types of allergies, symptoms, and results are across a broad spectrum. For example, numerous studies have shown that allergic rhinitis responses to the household dust mite decrease significantly in adults and children when probiotics were used. However, people allergic to birch pollen saw neither a decrease in general allergic responses to birch pollen or to apple food.
We found the most evidence linking strains to antibiotic recovery, immune health, and IBS/IBD relief. We made checklists of the most researched strains that treat those issues (10 strains known to boost general health, six for immune health, seven for antibiotic recovery, and seven for IBS/IBD relief) and dug into ingredient lists to find the supplements containing the highest number of effective strains for each use case.
Unlike MegaFood, the Renew Life label’s cold-storage recommendation is printed so small we nearly missed it (and it didn’t ship with a cold pack). If a probiotic requires refrigeration, be vigilant when buying it — the retailer that stores it or the company that ships it should keep it refrigerated until it gets to you. Otherwise, some of its potency might diminish in storage or transit.

Selecting a multi-strain probiotic is also consistent with the theory that filling your gut with enough good bacteria outcompetes any bad bacteria for the same space and resources. In your gut, the more diversified the good bacteria, the harder it is for the baddies to gain a foothold. With all this in mind, we only looked at supplements containing multiple strains of bacteria.
Animals, including humans, have microbes inside them that benefit them in multiple ways. These microbes are in a loose sense like probiotics, but the definition of probiotics was established to designate those microbes that have been isolated, studied, tested in a laboratory dish and/or clinically in animals and/ or humans, and proven to have beneficial properties. In many cases their genetic fingerprints were sequenced for identification purposes and also to check for potentially harmful genetic components. The official term “probiotics” established specific criteria for scientific studies and probiotic supplements, foods, and drinks.

Unless you have a perfect gut and are already eating lots of fermented foods—which is rare, although you can work up to this point—it’s difficult to get all the probiotics you need from diet alone. Most of us don’t have perfect guts—everything from antibiotics to high-carbohydrate diets to being born via a C-section can compromise the balance of bacteria in our microbiome. Supplementing with a probiotic can help to restore imbalances, and it’s also just a great preventative health measure, helping to keep your microbiome in balance and your immune system healthy to ward off illnesses.
Bacteria in your digestive tract can be good or bad, according to the website Best Probiotic. It quotes the Royal Academy of Medicine England as blaming an imbalance between good and bad bacteria for causing 80 percent of all degenerative diseases. Probiotic supplements with "good" bacteria have become increasingly popular. They can aid the immune system, digestion and vitamin absorption, as well as prevent diarrhea and irritable bowel syndrome. The website Women to Women recommends probiotics that combine saccharomyces, lactobacillus acidophilus and bifidobacteria in the billions. MayoClinic.com also recommends lactobacillus and advises looking for products that contain live, active cultures. You should always check with your doctor before adding any supplements to your diet.
​​​​​​AZO Complete Feminine BalanceTM is a daily probiotic supplement designed for the unique needs of women. Many everyday things can throw off your balance (stress, sex, pregnancy, aging, even medications! This product supports your feminine health and maintain a healthy pH so that you can own your day! It contains INTELLIFLORATM: a probiotic blend of four lactobacilli that are associated with vaginal health* (Lactobacillus crispatus LBV 88, Lactobacillus rhamnosus LBV 96, Lactobacillus jensenii LBV 116, and Lactobacillus gasseri LBV 150.)  The INTELLIFLORATM blend has been shown in clinical studies to help restore and maintain the healthy balance of the vaginal microbiota.*
Sugar is so easily accessible in Westernized cultures that it is easy to overindulge in it. But why do you crave it? There are several reasons. One, sugar usually means sucrose, which is composed of glucose and fructose. Glucose is the sugar in your blood, so consumption of sugar results in a temporary boost of energy. However, that blood-sugar spike causes insulin to be released to usher the sugar into cells for energy or fat storage, and shortly afterward your blood sugar drops. So then you feel a slump and reach for something to bring your blood sugar back up: more sugar.
The large intestine is home to hundreds of trillions of bacteria. Fortunately, most are neutral or even beneficial, performing many vital body functions. For example, they help keep “bad” bacteria at bay, play a role in immunity, help us digest food and absorb nutrients and may even have anticancer effects. But will consuming them as probiotics in foods or capsules make a notable difference to your health—especially if you are already healthy? Here’s a look at the evidence.

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Yes. Probiotics are incredibly important and effective. We know there are more bacteria in us and on us than our own human cells. The body is almost like a puppet—it is bacteria that really runs the show: They turn on enzymes, turn off genes, and dictate much of our health. We need them to break down nutrients, like copper and magnesium, so we can better absorb them. Interestingly, studies show that conditions like anxiety, depression, and weight gain can be transferred via fecal transplants (with mice), suggesting the broad impact bacteria has on health.

The science on what probiotics do is still emerging. There is some hard evidence that suggests eating probiotic foods and supplements can have a beneficial effect on health. Other evidence suggests probiotics benefits are limited to those individuals in good health and should be avoided by those who suffer from certain serious health conditions. There is no research that demonstrates the risks or the benefits of probiotic supplements on children.


An imbalance between good bacteria and pathogenic bacteria, yeasts or fungi, or a change in the bacteria species that colonize the digestive tract is called dysbiosis. It can have short and long-term effects on our body functions. These disruptions can reduce the immune system’s effectiveness, create unpleasant digestive symptoms (diarrhea, constipation, gas, etc.), be a contributor to certain chronic illnesses like obesity, and participate in producing pro-inflammatory metabolites.
Prebiotics and supplementary ingredients — For probiotic bacteria to grow, they also need prebiotics. High-quality probiotic supplements have both prebiotics and other ingredients designed to support digestion and immunity. Examples of these ingredients are (preferably fermented) flaxseed, chia seed, cañihua seed, astragalus, ashwagandha, hemp seed, pumpkin seed, milk thistle, peas, ginger, mung bean and turmeric.
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.
Made from aged, fermented soybeans, this paste is brimming with probiotics. You can buy miso paste in a bunch of varieties (white, yellow, red, brown) and the darker the color, the deeper the taste. Miso is a great way to add a burst of earthy, savory flavor for few calories (only 25 to 30 per tablespoon), plus protein, fiber, and bone-strengthening vitamin K, says Sharon Palmer, RDN, author of Plant-Powered for Life. "While we need more research about how these types of fermented foods contribute to health, it's a good idea to introduce more of them into your diet," she says. Use miso to glaze fish or chicken before cooking, mix into a stir-fry recipe, or add to liquid to make a miso broth. One caveat: Miso is very high in sodium. One teaspoon, enough to make a cup of miso soup, has 473 mg of sodium, 21% of the daily recommended limit and 32% of the daily limit for those with high blood pressure.

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.

Renew Life Ultimate Flora offers 30 billion CFUs with 10 scientifically studied strains of Bifidobacterium and Lactobacillus, which according to current scientific research, are the two most prevalent good bacteria found in a healthy gut. In other words, you might choose these if you’re seeking a careful balance designed to re-establish proper immune health and digestive equilibrium.


We love that RAW offers proprietary blends for various needs, including specialty formulas for women and men. Both support the standard systems (immune, digestive, etc.), and the women’s probiotic tacks on extras, including L. reuteri and L. rhamnosus, to support vaginal health. The men’s blend adds L .fermentum, to boost immunity during exercise and other physical exertion.
Unfortunately, the U.S. has no federal standards for probiotic supplements. Therefore, you run the risk of purchasing a product without any guarantee that it contains its advertised probiotic strains, that the strains are alive, or that the product is free from unhealthy ingredients. Therefore, it may be best to choose a brand-name probiotic that has research backing their effectiveness. Here are some examples:
There’s preliminary evidence that some probiotics are helpful in preventing diarrhea caused by infections and antibiotics and in improving symptoms of irritable bowel syndrome, but more needs to be learned. We still don’t know which probiotics are helpful and which are not. We also don’t know how much of the probiotic people would have to take or who would most likely benefit from taking probiotics. Even for the conditions that have been studied the most, researchers are still working toward finding the answers to these questions.
“It’s been proposed—but not proven—that regular probiotic intake may help prevent this change [with age],” says Emeran A. Mayer, M.D., a professor of medicine and psychiatry at the David Geffen School of Medicine at UCLA and author of “The Mind-Gut Connection” (Harper Wave, 2016). “We’re just starting to scratch the surface of this area of research.”
Until recently, testing of probiotics by ConsumerLab.com found that some products had far lower amounts of live organisms than claimed on the labels. But in 2018, it found that 17 out of 18 products tested contained the amounts listed; none exceeded limits for heavy metal contaminants. In contrast, in 2016, a study in Pediatric Research found that only one out of 16 Bifidobacterium longum supplements tested contained the species named on the label.
They probably are. Lebwohl says probiotics may decrease the risk of getting diarrhea during the course of taking antibiotics, and may also play a role in specifically preventing the development of the dreaded antibiotic-related super diarrhea called C. difficile or C. diff. Antibiotics can wipe out the good bacteria that keep you from getting sick if you’re exposed to C. diff, or if you already have it in your system. C. diff symptoms can range from a moderate watery diarrhea several times a day to severe infections, which can be accompanied by fever, bloody stools, rapid heart rate, and can even lead to kidney failure. 500,000 Americans were infected with C. diff in 2015 and 15,000 died from it.
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