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.

The National Institute of Health (NIH) is sponsoring the Human Microbiome Project (HMP), which is developing research resources to enable the study of the microbial communities that live in and on our bodies and the roles they play in human health and disease. The NIH has funded many more medical studies using HMP data and techniques, including the role of the gut microbiome in Crohn's disease, ulcerative colitis, and esophageal cancer; skin microbiome in psoriasis, atopic dermatitis, and immunodeficiency; urogenital microbiome in reproductive and sexual history and circumcision; and a number of childhood disorders, including pediatric abdominal pain, intestinal inflammation, and necrotizing enterocolitis, a severe condition in premature infants in which the intestine tissue dies due to lack of oxygen.

Probiotics stick around for a while, though for how long isn’t precisely clear. You have to keep taking them to continue to reap the benefits. Further, getting a wide variety of strains into your system is beneficial. “Periodically mixing up your probiotic supplement is also a good way to ensure that you get different health-building strains in your health regime,” says Dr. Cook.
Lactobacillus predominantly live in your small bowel (the portion of your gut that follows the stomach). Probiotics containing Lactobacillus sp. help to repopulate the small intestine with friendly organisms that aid in supporting digestion and immune function. The most beneficial are L. acidophilus, L. plantarum, and L. paracasei. One study found Lactobacillus acidophilus could reduce gut inflammation. L. rhamnosus helps increase GABA expression (an inhibitory neurotransmitter that helps you feel relaxed) in the brain, resulting in lower anxiety and depression-related behavior. Another found that a combination of Lactobacillus and Bifidobacteria (which we'll talk about next) improved symptoms of bloating in patients with functional bowel disorders, and yet another found that when people took the Lactobacillus rhamnosus GG strain, it significantly reduced the risk for antibiotic-associated diarrhea.
If you've ever been to an Indian restaurant, then you've probably seen a lassi—a smoothie made of milk, yogurt, fruit, honey, and cardamom. The drink goes well with spicy Indian food because it helps extinguish the fiery feeling in your mouth. If you want to try it at home, you can pick up bottles from brands like Dahlicious, which contain 15 billion live probiotics per serving and are available in flavors like mango and turmeric. Or, try this mango lassi recipe.

Myriad factors – antibiotics, diet, stress, and age, among them – affect the balance of diverse microbes present in your gut. While you can replenish your gut bacteria by eating well and incorporating natural probiotics (ex. yogurt and kefir) into a healthy diet, these processes can take weeks or months; taking a regular probiotic is an easy and effective way to ensure your gut (and immune system) stays healthy, always.
My husband is battling lung cancer and Sarcoma and has a lot of gut issues such as nausea and vomiting which have caused him to lose a significant amount of weight. To help with the N/V a probiotic was recommend. I’d like to try him on the BlueBiotics Ultimate Care but am concerned that by doing so it will cause him to lose even more weight which he has no extra weight to spare. What are your thoughts on this?
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.
You may have heard some questions over whether SBOs are safe: The NIH has a presumed case report, which hasn’t been 100 percent verified, of someone with Lymphoma getting septicemia from taking a SBO (the organism B. subtilis). Some say that if you have leaky gut, you should heal it before supplementing with SBOs. If you are immunocompromised or have cancer, you can consult with a physician first to be safe.
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."
In the 2016 paper, Dr. Ghannoum and is research partners looked at parameters of microbiome makeup in Crohn’s Disease patients and healthy members of the same families in an area in Belgium.  The researchers said they “​identified positive interkingdom correlations between C.​ ​tropicalis​ (a fungus), E.​ ​coli, and S.​ ​marcescens​ (both microbial species) ​in CD patients and validated these correlations using in vitro biofilms​. These results provide insight into the roles of bacteria and fungi in CD.​”​
Some studies suggest that certain probiotic strains may also help in mild to moderate ulcerative colitis and possibly for bloating and gas in irritable bowel syndrome (IBS). Probiotic supplements, on the whole, “improve global symptoms, bloating, and flatulence in IBS,” by modifying the gut microbiome, according to a 2014 monograph from the American College of Gastroenterology. As IBS researchers said in a paper in Gastroenterology & Hepatology in 2015, “The concept of manipulating the microbiome is one of the most promising new ways in which to treat patients with IBS, but there is still much to learn.”
Immunity and colds/flu.There’s a close connection between the bacteria in your colon and the immune system. Several studies, including one in 2012 in the British Journal of Nutrition, have found that certain probiotic strains boost measures of immune response—but whether this translates into any clinical benefits is uncertain. Studies have been inconsistent, for example, as to whether probiotics will actually curb colds and other upper respiratory infections. In 2014 a review in the British Journal of Nutrition, which looked at 20 clinical trials, linked probiotics to shorter duration of colds, but not necessarily reduced incidence or severity. Similarly, a 2015 Cochrane review of 12 clinical trials concluded that certain probiotics may help prevent or shorten such infections, though the quality of the studies was poor.
Probiotics for allergies are fast becoming a preferred treatment method because they are understood to be much safer than traditional allergic rhinitis medication. A nasal spray for allergies is often a ‘go to’ treatment, for example, but allergy nose spray medications often contain corticosteroids, like Beclometasone dipropionate, which could affect bone metabolism, blood cells, and the pituitary gland.
Caution needs to be taken by everyone who chooses to take these supplements, but this is especially true for children, pregnant women, elderly people, and people with compromised immune systems. For people with compromised immune systems due to disease or treatment for a disease (such as cancer chemotherapy), taking probiotics may actually increase one's chances of getting sick. It has been shown that the use of various probiotics for immunocompromised patients or patients with a leaky gut has resulted in infections and sepsis (infection of the bloodstream). One case of bacteremia (bacteria in the bloodstream) was recently found when someone with active severe inflammatory bowel diseases with mucosal disruption was given Lactobacillus GG. Always speak with a doctor before taking any supplement under these circumstances.

"The proprietary formula in this lotion supports a healthy microbiome of your skin promoting a more hydrated, stronger barrier function and protection from pathogens without harming the good stuff. Throw away your antibacterial soap and hand sanitizer and use this all over after your shower and after washing your hands," says Astarita, who is also a fan of the Nerium Prolistic Powder Pre & Probiotic Plus Vitamins ($45) and Be Well Probiotic Powder ($46) by Dr. Frank Lipman.


But what if investigators could design probiotics to treat specific individuals? Many researchers think personalized probiotics are the most promising path forward for patients with compromised gut microbiomes. Last year Jens Walter of the University of Alberta and his colleagues published a study that gives a glimpse of this potential future. The researchers decided to see what it would take to get the bacteria in a probiotic to successfully colonize the intestines of 23 volunteers. They chose a particular strain of Bifidobacterium longum that earlier studies had indicated could survive in the human intestine. In the study, the volunteers consumed either a drink containing 10 billion live B. longum bacteria or a placebo in the form of a glucose-based food additive (maltodextrin) each day for two weeks. Periodic fecal samples revealed higher than typical levels of B. longum in participants who did not consume the placebo.
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.
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While raw probiotics tend to be the freshest (and most effective!) cultures on the market, it is important to ensure that you will store these properly in between each use. Cultures can die unrefrigerated in as little as a few hours, rendering them completely ineffective and, if you’re especially unlucky, even harmful to your body’s natural flora. Think about it, when has stale or moldy bread made your tummy feel better? The same thing goes for stale probiotic cultures!
For most of my life, I thought of probiotics as something I’d only drink if I lost a bet. Then stress-induced irritable bowel syndrome (IBS) turned my intestinal tract into a nonstop river of shit—we’re talking weeks of everything I ate shooting straight out my butt in liquid form. The internet said probiotics were my best non-pharmaceutical bet to help my digestive system calm down, so I swallowed my pride (and my first kombucha ever) and kinda sorta saw the light. My IBS wasn’t cured, but probiotics did help me spend less time on the toilet wide-eyed with terror, and more time doing what’s really important in life—watching TV with my family.
Back to the question of what are probiotics: There are five main types, each in its own classification called a genus. Within each genus there are multiple species, and within those species there are multiple strains. For example, Lactobacillus is a very common genus of probiotics. Within that genus are numerous species, such as rhamnosus. The genus and species of a microbe are always italicized, making it easy to know that a microbe is involved. In a species such as Lactobacillus rhamnosus (often abbreviated L. rhamnosus), there are many strains. An example of the name of a strain is L. rhamnosus GR-1.
There are both probiotics and prebiotics in fermented foods. I differ from a lot of doctors in that I recommend that patients with infections like Candida and SIBO don’t eat prebiotics until they’ve cleared up the infection—because the prebiotics can feed those infections, too. I find that it’s better to get rid of those infections first, and then add in prebiotics to your diet after. [See here for more from Dr. Myers on treating yeast infections.]

Today, most of the Japanese population begins the day with a warm bowl of miso soup, believed to stimulate the digestive system and energize the body. Made from fermented soybeans, rice or barley, adding a tablespoon of miso to some hot water makes an excellent, quick, probiotic-rich soup. The fermentation process can take anywhere from a few days to a couple of years to complete, and the end result is a red, white or dark brown paste with a buttery texture.
If you’re new to Bio-K+, know that each bottle contains 50 billion live and active probiotic bacteria. Probiotics are good for a wide variety of digestive issues, so it’s best to customize your dosage based on what your specific needs are. If you are looking to take a preventative dosage to support the health of your microbiome, start with a ¼ bottle per day. If you suffer from digestive health issues or regularly take antacids, start with a ½ bottle of Bio-K+ per day. If you have more serious gastrointestinal issues or have had to take antibiotics, Bio-K+ probiotics are great for getting your system back on track. Start with a full bottle per day and see how you feel (we’ve had amazing results from our fans!)
What’s more, your bacterial makeup does more than just boost or bully your immune system; the existence of good and bad bacteria affect your mood and energy levels, relieve (or contribute to) a sensitive stomach (including lactose intolerance and irritable bowel syndrome/IBS), affect your mood, and even support (or hinder) a healthy body weight. (Fascinating fact: Scientists can predict weight with 90% accuracy based on your gut’s bacterial makeup, but only with 58% accuracy based on your genes. Bacteria counts!)
The Golive Berry Probiotic and Prebiotic Supplement Blend is perfect for tossing in your bag or keeping in your desk. Each packet includes 15 billion CFUs and 15 different probiotic strains. It also has a soluble fiber prebiotic to promote the growth of good bacteria in your body. Each packet contains 30 calories and comes in five flavors including pomegranate, melon cucumber, citrus blueberry, and a flavorless option. It can be mixed in any hot or cold drink, but we recommend tossing the flavored packet into a bottle of water. You’ll get 10 packets in each order.

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.
In addition to its powerful probiotic strands, the Vitamin Bounty Women’s Pro-Daily Probiotic also features a proprietary women’s health formula. This blend includes many of the minerals and plant extracts that have been found to be the most beneficial to women’s health, making it ideal for any women that have experienced feminine health problems. Specifically, this Vitamin Bounty formula includes Ashwagandha Root Powder, Cranberry Fruit Powder and Black Cohosh Root Powder.
Hi Joan, it’s possible, but not ideal because most pill form probiotic supplements are designed to be protected from stomach acid until the capsule reaches the intestines. It’s impossible to say how many probiotic microorganisms would survive by taking them this way, but certainly less than if you swallow the pills. I would recommend trying a probiotic gummy product or some other probiotic that comes in something other than pill form rather than opening up the capsules.
This mildly sour, chewy bread is made with a lactic acid starter that contains strains of lactobacillus, a friendly type of bacteria that adds good microbes into the bakery staple. Sourdough may be the healthiest bread choice if diabetes is a concern for you: one 2008 study found that people with pre-diabetes who ate sourdough bread had less of a blood sugar spike compared to when they ate bread made with baker's yeast. (Experts also say fiber-rich whole grain bread can also reduce a post-meal blood sugar spike.) The researchers credit the lactic acid for the favorable effect.
Many factors influence the proportion of each family; from the early years of your life (the type of birth you had, breastfed vs. formula-fed, exposed to antibiotics prenatally) to the later years, where more lifestyle factors like diet, smoking, alcohol consumption, stress, and sleep come into play. The bacteria species found in the digestive tract have a significant influence on overall health, both physical and mental, which is why it’s important to take care of them every day.
Others scientists are more hopeful. Finding out how exactly probiotics work in regards to allergies is an important step in that process. Some studies show that some strains of bacteria can affect how our T cells (an immune cell responsible for the big immune responses) function. Others suggest that they may reduce the production of a part of the immune system called immunoglobulin E, which is produced in excess during an allergic reaction.
Because there's a huge variety of probiotic products available on the market, many people struggle to find the right one for them. "There are many different strains of bacteria in different combinations within different probiotic supplements," explains Brooke Scheller, a clinical and functional nutritionist. "For example, a probiotic may contain a single strain of bacteria or many. It may also contain other vitamins, minerals, or other ingredients that may tout health benefits," she says. There are many different dosages, delivery systems (powder, tablets, capsules), and formulations (refrigerated vs. shelf-stable), and some probiotics also contain prebiotics, which basically act as fertilizer for the probiotics. (Related: Why Your Probiotic Needs a Prebiotic Partner)

Third-party testing: Lastly, it's important to remember that probiotics are an unregulated supplement. "Find out whether there is third-party data verifying the potency, purity, and effectiveness of the product," suggests Dena Norton, a registered dietitian and holistic nutrition coach. "Remember that dietary supplements aren't regulated, so you can't necessarily just trust the claims on the label." Check out AEProbio, a site that has compiled research on specific brands of probiotics available in the U.S., recommends Scarlata, and an NSF seal is always a good marker to look for.
If you've tried a probiotic after following these steps and it doesn't seem to be working for you (or you just want some extra guidance in choosing one), head to your doctor (or a dietitian) to get a recommendation. "Have a thorough discussion with your doctor to make sure you are taking the appropriate bacterial strain for the appropriate reason," advises Dr. Ivanina. "Then, follow up after taking the probiotic to make sure it is having the intended effect."
Probiotics' side effects, if they occur, tend to be mild and digestive (such as gas or bloating). More serious effects have been seen in some people. Probiotics might theoretically cause infections that need to be treated with antibiotics, especially in people with underlying health conditions. They could also cause unhealthy metabolic activities, too much stimulation of the immune system, or gene transfer (insertion of genetic material into a cell).

"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," says Segal. "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."

More than 80 years later, probiotics have become wildly popular and incredibly profitable. A 2012 survey by the National Institutes of Health showed that 3.9 million Americans stated they had used some form of probiotics or prebiotics (a type of dietary fiber thought to feed the friendly bacteria in your gut) in the last 30 days—3 million more people than in the previous study in 2007. Probiotics are now available for consumption in almost every imaginable form—pills, tablets, yogurts, juices, cereals, and energy bars. They have been touted as having benefits not only for digestive health, but also mood disorders, cancer, cold and flu prevention, and reproductive health issues.
Jotham Suez, Niv Zmora, Gili Zilberman-Schapira, Uria Mor, Mally Dori-Bachash, Stavros Bashiardes, Maya Zur, Dana Regev-Lehavi, Rotem Ben-Zeev Brik, Sara Federici, Max Horn, Yotam Cohen, Andreas E. Moor, David Zeevi, Tal Korem, Eran Kotler, Alon Harmelin, Shalev Itzkovitz, Nitsan Maharshak, Oren Shibolet, Meirav Pevsner-Fischer, Hagit Shapiro, Itai Sharon, Zamir Halpern, Eran Segal, Eran Elinav. Post-Antibiotic Gut Mucosal Microbiome Reconstitution Is Impaired by Probiotics and Improved by Autologous FMT. Cell, 2018; 174 (6): 1406 DOI: 10.1016/j.cell.2018.08.047
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:
Unlike other probiotics on the market that are shelf stable, Garden of Life’s Raw Probiotics for Women are completely raw and alive at the time of delivery. In fact, these probiotics are so fresh that they are shipped in cold storage and delivery to keep all of those helpful cultures alive during transport and will need to be popped in your fridge immediately upon arrival.
Make sure to keep them away from moisture and heat which can kill off some of the microbes. I recommend taking on an empty stomach, ideally right when you wake up. You should always store supplements in a cool, dark place but refrigeration is best. Most of the strains of probiotics are fragile and should be protected from heat- so refrigeration is ideal. I recommend the probiotic Gut Instinct from HUM Nutrition for transparency and high quality.
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.
Unless you know that your body is lacking in a particular type of probiotic, you should just look for broad-spectrum probiotics that contain a mix of different strains of bacteria, Warren says: "We have billions of bacteria in our gut, so by taking a supplement with a range of different strains, you will ensure you are not overdoing or missing one type." Keatley also stresses the importance of finding a supplement with a diversity of bacteria strains to keep overgrowth of any one strain in check. "Providing too much of an advantage to one strain of probiotic may push out another strain we didn't know was important until it's too late," she points out.
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.
I did the “milk test” on these New Rythm probiotics, along with Culturelle I had purchased in 2 different states (TX & MA, as I was traveling); my mother’s CVS brand acidophilus; and one “control” cup with milk only (so, 5 cups total in my experiment). The New Rythm became a solid yogurt consistency, while the other 4 remained liquids. I did the experiment twice, just to be sure of the results. I could not believe it!!! New Rhythm is my brand, hands down!!! I also would like to mention that my product usually arrives the day after it ships. So it will take a few days to ship when I select standard shipping, which is to be expected, but it doesn’t stay in transit long which is ideal for preserving the living cultures.
Unfortunately, many commercial brands don’t measure up. They are unstable in stomach acid. Quality control measures aren’t intact, including ensuring supplements have been handled correctly and maintain their freshness. Moisture slipping into probiotic supplements can reduce their efficacy. Companies that use bioshield capsules produce higher quality probiotic supplements that are able to endure the stomach acid, releasing their contents within the small intestine, where a more alkaline environment ensures the survival of the bacteria.
Make sure dosages are listed in CFU, colony forming units. (Most brands list CFU in billions now: so 30 billion CFU, 100 billion CFU, and so on.) For one, this means that the bacteria strains are living, which is essential. When you’re looking at the cost of products, be sure to look at the cost per unit. I spoke to a woman the other day who had bought probiotics that had 2 billion CFU per capsule. In comparison, to get the 30 billion CFU I recommend, she’d have to take essentially half of her bottle to get the same dosage as one of our capsules.
Unlike other probiotics on the market that are shelf stable, Garden of Life’s Raw Probiotics for Women are completely raw and alive at the time of delivery. In fact, these probiotics are so fresh that they are shipped in cold storage and delivery to keep all of those helpful cultures alive during transport and will need to be popped in your fridge immediately upon arrival.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
We are clearly getting to the strain level by going beyond “Saccharomyces boulardii” and to “Saccharomyces boulardii CNCM I-745”. They did a great job by actually putting it on the label so you don’t even have to contact the company to see exactly what strain you’re getting. (P.S. this is a well-researched strain that I highly recommend, especially for preventing antibiotic-associated diarrhea.)
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