What Are Probiotics Actually Helpful For (According to the Science)?

Nowadays, talk of probiotics is everywhere. They are often touted for their beneficial effects on everything from skin conditions to the common cold. There are also a lot of articles that claim probiotics are useless and merely another marketing ploy by supplement companies. We are not about taking expensive supplements for nothing! In our experience working with clients, if used for the right reason and from a reputable company (usually in conjunction with other treatments), probiotics can be very helpful.

In light of some of this confusion, below we have outlined what the research says about some of the conditions that probiotics may help alleviate. There are hundreds of known strains of probiotic bacteria, all with different functions, so we have outlined which strains are linked to the positive research.

Antibiotic-Associated Diarrhea

The Research:

It’s estimated that we have trillions of bacteria that live in our gut, most of which play an important role in our health, including our immunity, hormones, digestion, mood, etc. Antibiotics work by killing off bacteria but cannot distinguish between "good" and "bad" bacteria. If the natural balance of the gut flora is disturbed, the "bad" bacteria can sometimes predominate and trigger loose stools and diarrhea.

A review of 63 randomized controlled trials (which is when some of the participants receive an experimental treatment and some participants receive either a placebo or conventional treatment and they compare the results) found that the pooled evidence suggests that probiotics are associated with a reduced risk of antibiotic associated diarrhea. Probiotics can help restore the balance of bacteria in the digestive tract, which the antibiotics may have disturbed. The majority of these studies used lactobacilli strains either alone or in combination with others. The researchers also found, which you’ll find in nearly all of the conditions we list in this post, a wide variation in results and that there isn’t enough evidence to determine how much this association varies by population, antibiotic or dose and type of probiotic.


Supplementing with a probiotic supplement containing, at a minimum, lactobacilli strains, during and following a course of antibiotics may help reduce antibiotic-associated diarrhea. We always recommend probiotics to our clients who have used antibiotics or other antibacterial herbs and have found them to be really helpful for restoring gut health.

Irritable Bowel Syndrome (IBS)

The Research:

A review of randomized controlled trials comparing probiotics with a placebo, up until 2008, found that probiotics appear to be effective in reducing symptoms of IBS. The review did find that the most effective species and strain(s) are still uncertain. Another 2015 review concluded that probiotics reduce pain and severity of symptoms in people with IBS. In general, it appears that lactobacilli and bifidobacterium strains, which are the most common ones found in probiotic supplements, seem to be the most effective in easing IBS symptoms.


In the research and in our experience working with people with IBS, people with IBS benefit from a good quality probiotic containing lactobacillus and bifidobacterium strains, in conjunction with other treatment options.


The Research:

A review of 14 well-done studies (as defined by the researchers) found that probiotics may be beneficial for relieving constipation, specifically by improving gut transit time (the amount of time it takes for food to travel to your large intestine), frequency of bowel movements and consistency. Bifidobacterium lactis in particular appeared to improve symptoms the most. This research shows that supplementing with bifidobacterium strains of probiotics may be beneficial in reducing constipation however, like we have seen so far with other symptoms, the results varied a lot and the right dose is still unclear.


Supplementing with probiotics that include bifidobacterium lactis and other bifidobacterium strains can help relieve constipation. From our client experience, probiotics in conjunction with addressing the root causes of constipation, like increasing fiber intake, improving stomach acid and digestive enzyme secretion and addressing food sensitivities is really effective for improving constipation.

What Are Probiotics Actually Helpful For (According to the Science)?

Lactose Intolerance

The Research:

It’s estimated that over 60 percent of the population does not have enough of the lactase enzymes to properly digest lactose. Some people who have a hard time digestive lactose products don’t have an issue with their fermented counterparts, like yogurt or kefir. This is because the live bacteria in these products help to predigest the lactose (bacteria eat sugar and lactose is a sugar), thereby reducing the lactose content and making it easier on your digestive system.

Researchers have identified a few of the strains in fermented dairy products to see if they would be beneficial in supplement form. Two bacteria found in yogurt are the lactic acid bacteria Lactobacillus bulgaricus and Streptococcus thermophilus. A review of 15 key studies studying the effectiveness of probiotics on lactose intolerance found that the presence of these bacteria may help reduce symptoms of lactose intolerance. They also found that bifidobacterium animalis was among the most researched and most effective against lactose intolerance. Another study gave individuals with lactose intolerance a specific strain of lactobacillus acidophilus or a placebo for 4 weeks. After the 4 weeks, the participants who received the l. Acidophilus reported significant reductions of symptoms of lactose intolerance.


This shows that depending on the individual (because the degree of intolerance and symptoms vary), supplementing with a probiotic with lactobacillus acidophilus and bifidobacterium strains may help reduce symptoms of lactose intolerance. Keep in mind there is also a difference between lactose intolerance and a dairy allergy or sensitivity and this research does not apply to those of you with the latter two. We’ve found that proper gut healing (which includes improving gut flora through fermented foods or probiotics) is critical to being able to tolerate foods you are sensitive or intolerant to.


The Research:

Probiotics protect against immune dysfunction and inflammation - two factors in the development and severity of eczema. So far, the research is mixed. A report published by the American Journal of Clinical Dermatology that reviewed 13 clinical trials on probiotics and atopic dermatitis, a kind of eczema, found that probiotics especially lactobacillus rhamnosus GG, but not lactobacillus acidophilus, appear to be prevent atopic dermatitis and reduced the severity of symptoms in half of the trials. Another review of 12 clinic trials however found that probiotics were no more effective than a placebo when it came to the severity of symptoms.


According to the research, supplementing with lactobacillus rhamnosus GG may reduce symptoms of eczema. In our own anecdotal experience with clients, probiotics do help, but usually only in addition to removal of dietary and environmental triggers.


The Research:

Research shows that children with allergies in general, seem to have lower levels of beneficial bacteria in their gut, higher levels by comparison of some of the more pathogenic strains and low diversity of strains. A big factor in this is heredity, so if the parents have allergies, as well as whether antibiotics were administered in their first year of life. One study found that early colonization by lactobacillus seems to decrease the risk for allergy development in children, even despite allergic heredity. This suggests that early supplementation with lactobacillus may help prevent or reduce allergies in children. More research needs to be done to draw more conclusive recommendations.


Children who have a family history of allergies or who have been given antibiotics in vitro or in their first year of life will likely benefit from a probiotic that contains at a minimum, lactobacillus strains.

Prevention of Recurrent Urinary Tract Infections (UTIs)

The Research:

Most of the recurrent UTIs in women occur because of E. coli bacteria. Antibiotics are used to treat these infections, which reduces the number of “good” bacteria, especially lactobacillus, which can destroy the body’s natural defence against recurrent infections. Not to mention that frequent use of antibiotics can also lead to antibiotic resistance, making this an ongoing battle.

Studies have found that specific strains of lactobacilli, including the rhamnosus GR-1 and fermentum RC-14 strains, when taken orally, will make it to the vagina, and stay and colonize it, thereby contributing to a healthier flora in the urinary tract. In this study specifically, researchers found that supplementing with at least 10 billion CFU (of live, viable bacteria) of a combination of these two strains per day was the required dose to colonize the urinary tract. The researchers also found that lactobacillus rhamnosus GG did not have an effect on the flora of the urinary tract, showing just how important different strains can be. Another randomized controlled trial involving treatment of UTI with a probiotic containing lactobacillus bacteria, reported a 73 percent reduction in episodes of recurrent UTI compared with the previous year (6 UTIs per patient per year vs.1.3 UTIs per patient per year after administration of probiotics).


Supplementing with a probiotic can be helpful for preventing recurrent UTIs by restoring a healthy gut flora, since low numbers of beneficial bacteria can make you more susceptible to developing a UTI. Look for probiotics specifically designed for women’s vaginal health and if possible, look for lactobacillus rhamnosus and fermentum.

Closing Thoughts

The research on probiotics shows that they can be beneficial for treating a number of different conditions. Not all probiotics are created equally and the specific strain matters. When you see a headline that comes out saying probiotics are useless or don’t work - take it with a very large grain of salt! It depends on the strain they were testing.

What we don’t want you to forget too is that you can get many of the beneficial bacteria from fermented foods as well - things like sauerkraut, kimchi or low sugar kombucha. These can provide a whole host of 

Lastly, probiotics should not be viewed as the be-all and end-all. When we are working with you to heal your gut, probiotics are one (important) piece of the puzzle. For example, probiotics alone are unlikely to resolve IBS. However, probiotics in conjunction with a protocol that addresses other root causes of IBS, the right diet, healing nutrients, lifestyle management and more (all of which we can help you with!), can put IBS completely into remission!

If you would like help healing your gut, whether it be IBS, gas, bloating, constipation or diarrhea, click here to book a complimentary info session to learn more about how we can help you.

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