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.

“Some strains have been shown to help with GI complaints, some with immune function, and some even have been shown to have benefits outside the intestinal tract, such as with vaginal health or eczema,” says Gail Cresci, Ph.D., R.D., a Cleveland Clinic researcher who studies the microbiome. But there are few definitive conclusions from the current research.


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.
From upset tummies to the common cold and everything in between, it seems as though the entire world is exclaiming, “there’s a supplement for that!” these days. Call it a symptom of the Aquarian Age, the fact that Amazon recently bought out Whole Foods, or simply that Western society is catching up with what other parts of the world have known for centuries but, for better or worse, everyone seems to be ditching the traditional meds in favor of a more holistic approach to wellness.
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 Number of CFUs The quality of a probiotic supplement has more to do with strains and how many CFUs it provides. (CFU stands for colony forming units, and it refers to the amount of live microorganisms in your supplement.) Although recommendations may vary, Gans says to look for probiotics with at least 1 billion CFUs: “Doses will typically range from 1 billion to 10 billion CFUs for adults; although doses for children are often under 1 billion.”
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.
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.
Step No. 1 is consume more sour foods — it’s the top way probiotics benefits can be accessed. Embrace what I call “the power of sour” with sour foods like apple cider vinegar and fermented vegetables. They contain some probiotics, but also they contain certain types of acids like gluconic acid and acetic acid, healthy acids that support the function of probiotics (even functioning like prebiotics in some cases).
The right resident strains - quite a few probiotics on the market contain things like active yeasts or soil based organisms. While these ingredients may be helpful to some, if you want to optimize your gut health, you need to look for strains that are resident to the human gut like those from the Lactobacillus, Bifidobacterium, and Streptococcus families.
Historically, people had plenty of probiotics in their diets from eating fresh foods from good soil and by fermenting foods to keep them from spoiling. Over a century ago, the Russian Nobel Prize winner Elie Metchnikoff theorized that “health could be enhanced and senility delayed by manipulating the intestinal microbiome with host-friendly bacteria found in yogurt.” Metchnikoff was ahead of his time with his view of probiotics benefits, but he also was aware that most citizens had regular access to probiotic foods.
Historically, people had plenty of probiotics in their diets from eating fresh foods from good soil and by fermenting foods to keep them from spoiling. Over a century ago, the Russian Nobel Prize winner Elie Metchnikoff theorized that “health could be enhanced and senility delayed by manipulating the intestinal microbiome with host-friendly bacteria found in yogurt.” Metchnikoff was ahead of his time with his view of probiotics benefits, but he also was aware that most citizens had regular access to probiotic foods.

What exactly do probiotics do? They are believed to protect us in two ways. The first is the role that they play in our digestive tract. We know that our digestive tract needs a healthy balance between the good and bad bacteria, so what gets in the way of this? It looks like our lifestyle is both the problem and the solution. Poor food choices, emotional stress, lack of sleep, antibiotic overuse, other drugs, and environmental influences can all shift the balance in favor of the bad bacteria.
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