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?

What are the benefits of taking probiotics? Bacteria have a reputation for causing disease, so the idea of tossing down a few billion a day for your health might seem — literally and figuratively — hard to swallow. But a growing body of scientific evidence suggests that you can treat and even prevent some illnesses with foods and supplements containing certain kinds of live bacteria. Northern Europeans consume a lot of these beneficial microorganisms, called probiotics (from pro and biota, meaning "for life"), because of their tradition of eating foods fermented with bacteria, such as yogurt. Probiotic-laced beverages are also big business in Japan.
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.
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.

Although many manufacturers will make claims regarding the benefit of probiotics for all sorts of disorders, there is not always research to back up those claims. It can be difficult to conduct quality research on probiotics due to the wide variety of strains available. And many studies show mixed results. However, given that, there is some research support for the use of probiotics for the following health conditions:
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.
That's because issues that can be treated with probiotics stem from specific imbalances in the amount of certain bacterial strains, according to Elena Ivanina, M.D., a gastroenterologist at Lenox Hill Hospital. "Therefore, if someone decides to supplement a particular strain of Lactobacillus, but they already have enough of that strain in their gut and their disease does not stem from a lack of Lactobacillus, then they will not have a response." Makes sense, right?
You experience that afternoon slump and reach for a candy bar or a sugar-laden coffee. Or maybe you go through your day, starting with a breakfast of doughnuts or sugary cereal, and then proceed to sodas for drinks, cookies to snack on, dessert after dinner, and finally to a nighttime snack of ice cream. You know that feeling; it’s that I-have-to-have-something-sweet-and- I-have-to-have-it-NOW feeling.
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.
Gut flora makes up 70 to 80 percent of the human immune system. Too much bad bacteria can inflame and destroy intestinal walls, enter the bloodstream, and trigger a multitude of health issues — constipation, depression, skin problems, autoimmune disease, and even bad breath. Adding good bacteria protects the digestive tract from the harmful bacteria in sugars, pesticides, and saturated fats.
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.
In a separate study involving 21 healthy volunteers, also published today in Cell, the same group of researchers found that taking probiotics after treatment with broad spectrum antibiotics may actually delay the return of people's normal gut microbiome. This goes against the idea that probiotics can help "repopulate" people's gut bacteria after antibiotics wipe them out.

The term "prebiotics" is often thrown around when probiotics are mentioned, and they're related to probiotics in a sense. According to Angelone, prebiotics are complex sugars that we don't digest but that are used as fuel by bacteria — including probiotics — that's already in your gut. Registered dietitian-nutritionist Beth Warren, founder of Beth Warren Nutrition and author of Living a Real Life with Real Food, explains that you can think of prebiotics as food for probiotics. You can get prebiotics from foods including asparagus, bananas, garlic, and onions, she says.


The takeaway: Certain strains were found useful in preventing diarrhea among children being prescribed antibiotics. A 2013 review showed that after antibiotic use, probiotics help prevent Clostridium difficile-associated diarrhea. A review focused on acute infectious diarrhea found a benefit, again for certain strains of bacteria at controlled doses. There’s also evidence that they may help prevent necrotizing enterocolitis (a serious gastrointestinal condition) and death in preterm infants.

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.
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.

Also, it’s important to understand that probiotics are not a new idea. Throughout history, cultures have thrived on probiotics found in fermented foods and cultured foods, which were invented for food preservation long before the refrigerator. The process of fermentation has been lost in recent years, as it is no longer needed to preserve foods, meaning that we now lose out on those vital probiotics benefits.
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!)
Deep Immune Support Probiotics started with a simple premise: Most probiotic strains present on the market today cannot survive the acidic environment of the human digestive system. Additionally, most of the most powerful probiotics require refrigeration, meaning they won’t survive standard delivery services or even room temperatures during your commute or travel.
There are four significant takeaways from this study: (1) murine gut mucosal probiotic colonization is only mildly enhanced by antibiotics, (2) Human gut mucosal probiotic colonization is significantly enhanced by antibiotics, (3) After taking antibiotics, probiotics delay gut microbiome and transcriptome reconstitution in mice and humans, (4) Autologous fecal microbiome transplant (aFMT) restores mucosal microbiome and gut transcriptome reconstitution. 

L. Casei also made headlines when a study found it beneficial in relieving anxiety. The randomized, double-blind, placebo-controlled pilot study found supplementation with 24 billion units of the L. Casei strain Shirota led to a rise in probiotics Lactobacillus and Bifidobacterium, as well as a significant decrease in symptoms of anxiety and depression [2].
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).
Since the bulk of your natural flora exists in your gut, it makes sense that this is the part of your body that feels it most when bacteria become imbalanced. Women, in particular, can experience all kinds of digestive problems, particularly during hormone fluctuations. These are just some of the digestive symptoms a high-quality probiotic can help reduce and even treat:
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.
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.
"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."
Kimchi: This fermented vegetable is made from Chinese cabbage (beachu), radish, green onion, red pepper powder, garlic, ginger, and fermented seafood (jeotgal). Many bacteria have been found to be present and can include any of the following: Leuconostoc mesenteroides and Lactobacillus plantarum, L. mesenteroides, L. citreum, L. gasicomitatum, L. brevis, L. curvatus, L. plantarum, L. sakei, L. lactis, Pediococcus pentosaceus, Weissella confusa, and W. koreensis. A recent review linked the health benefits of kimchi to anticancer, antiobesity, anticonstipation, colon health promotion, cholesterol reduction, antioxidative and antiaging properties, brain health promotion, immune promotion, and skin health promotion.
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.

There are four significant takeaways from this study: (1) murine gut mucosal probiotic colonization is only mildly enhanced by antibiotics, (2) Human gut mucosal probiotic colonization is significantly enhanced by antibiotics, (3) After taking antibiotics, probiotics delay gut microbiome and transcriptome reconstitution in mice and humans, (4) Autologous fecal microbiome transplant (aFMT) restores mucosal microbiome and gut transcriptome reconstitution. 
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.
Probiotics can also help offset the bacterial imbalance caused by taking antibiotics. Antibiotics kill good bacteria along with the harmful ones, often leading to gas, cramping or diarrhea. Potential benefits of probiotics have been seen in the treatment or prevention of many conditions such as diarrhea, irritable bowel syndrome, ulcerative colitis, and Crohn's disease.
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.
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.
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.

​​​​​​Every woman’s microbiota is different and so results will vary. However clinical studies using the blend of probiotic strains in AZO Complete Feminine BalanceTM demonstrated benefits in as little as 7 days. We suggest continuing with use of the product for a minimum of 30 days. Also, keep in mind that for regular maintenance, you may not SEE results but the product is still helping to protect and maintain a healthy vaginal flora.*
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.
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.
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."
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!)
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.
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:
MegaFood is our only top pick that’s certified vegan, as well as being gluten free and dairy free, making it a good choice for any food-sensitive or vegan probiotic seeker. It has fewer of our wishlist “general health” strains than Vita Miracle, but it still contains five. This could be a go-to if you eat vegan, even if you’re not recovering post-antibiotic.
Vitamin Bounty’s probiotic contains a variety of well-studied strains and a competitive 25 Billion CFU. It also contains a natural prebiotic resistant starch, rice flour, to fuel the strains this probiotic supplies. Over 95% of Pro 25’s strains were still active and viable, the second highest observed strain viability out of all probiotics reviewed-to-date!
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.
After the antibiotics had cleared the way, the standard probiotics could easily colonize the gut of everyone in the second group, but to the team's surprise, this probiotic colonization prevented the host's normal microbiome and gut gene expression profile from returning to their normal state for months afterward. In contrast, the aFMT resulted in the third group's native gut microbiome and gene program returning to normal within days.
Russian microbiologist Elie Metchnikoff (1845-1916) was the first to associate the large amounts of fermented dairy products with the good health and longevity of Bulgarians back in 1907. He proposed that the acid-producing organisms in fermented dairy products could prevent what he called "fouling" in the large intestine. He believed if eaten regularly, these foods could lead to a longer, healthier life. One version of the Old Testament even attributes Abraham's long life — 175 years — to the "consumption of sour milk." Fermented milk products may have also been used to treat illnesses of the digestive tract during Roman times.
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.
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.
Most probiotics are like what is already in a person's digestive system. Some probiotics have been used for a very long time throughout history, such as in fermented foods and cultured milk products. These don't appear to cause illness. But more study is needed on the safety of probiotics in young children, the elderly, and people who have weak immune systems.
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.
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