In October 2013, the International Scientific Association for Probiotics and Prebiotics (ISAPP) organized a meeting of clinical and scientific experts on probiotics (with specialties in gastroenterology, pediatrics, family medicine, gut microbiota, microbiology of probiotic bacteria, microbial genetics, immunology, and food science) to reexamine the concept of probiotics. They define probiotics as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host." They also differentiated between products containing probiotics and those containing live or active cultures and established the following criteria:
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.∗
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.

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.
While more research is necessary to truly understand the widespread benefits of different probiotic strains, we do know that not all probiotics are created equal. The Lactobacilli, for instance, live in our digestive, urinary and genital systems and can be found in some fermented foods like yogurt. Bifidobacteria normally live in the intestines as lactic acid bacteria, and are also found in fermented foods. According to nutrition expert Alex Caspero, RD, “For certain conditions, you want to ensure you are taking the strand that is most likely to benefit you.” Here is a simple breakdown to help you determine the best probiotic for you.
"I usually recommend Garden of Life, BioK or Megafoods brand," says Shapiro. "I also recommend starting with about 30 billion CFU and making sure your supplement has at least 12 different strains. And if you don't eat a diet high in fruits, vegetables, nuts, seeds, and whole grains that provide fiber for the probiotics to live off of, make sure you're the one you are taking contains prebiotics as well.
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.
Given that you can get probiotics from the food you eat, you don't necessarily need to take a supplement, and Keatley says she prefers food sources of probiotics to supplements. However, she adds that "There are times when you really need a boost." One example might be during or after a course of antibiotics, as long as you have your doctor's OK, since antibiotics kill both good and bad bacteria: "Seeding your gut with good bacteria can lay the groundwork for a faster recovery and less constipation and diarrhea," Keatley points out. Angelone echoes Keatley's emphasis on food sources of probiotics, but also says that supplements can also play a useful role in "maintaining a healthy gut bacteria colony."
In seven people, however, these bacterial levels persisted for more than five months after the treatment ended. “We never expected they would survive more than a few weeks,” Walter says. A follow-up analysis determined that these seven people had begun the experiment with lower levels of B. longum in the first place. In other words, their gut ecosystems had a vacancy that the probiotic filled. That is exactly the kind of insight that clinicians need to create and recommend more effective probiotics. If a doctor knows that an individual with severe diarrhea has an undersized population of a particular beneficial microbe, for example, then prescribing the missing strain should increase the chance of a successful treatment.
Two large-scale clinical trials recently reported in the New England Journal of Medicine suggest that the situation in infectious diarrhoea might also be more complex than previously believed. Freedman and colleagues did a randomised controlled trial of a probiotic containing Lactobacillus rhamnosus and Lactobacillus helveticus in children presenting to the emergency department with gastroenteritis. Contrary to expectations, they found that the probiotic did not prevent development of moderate-to-severe gastroenteritis within 14 days after enrolment. In a separate study, Schnadower and colleagues found similar results with L rhamnosus GG alone. Both trials used probiotics that are available over the counter in North America and showed no significant difference from placebo in the duration of diarrhoea and vomiting, number of unscheduled health-care visits, or length of absence from day care. These results cannot be generalised to other probiotic strains or preparations, but they do show that we have some way to go in elucidating which probiotics might provide benefits in which clinical settings.
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.
When it comes to probiotics and supplements, fresher is always better! That’s why the Garden of Life Raw Probiotics for Women feature completely raw, live probiotics just as nature intended. This raw formula helps to promote bowel regularity, digestive function, and healthy nutrient absorption all while supporting recurrent constipation, colon irregularities, and vaginal health problems.
While this feature contributes to the efficiency of the product, it is unclear whether this product is vegetarian like some of the other probiotics we reviewed. Therefore, if you have any dietary restrictions or needs, this may not be the best probiotic for you and may, in fact, cause additional stomach upset or irritation. It is however gluten-free.
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