How to Choose the Best Probiotic for You

How to Choose the Best Probiotic for You

What to Know About Probiotics

If you had the chance to join us on our recent online workshop on digestion, you’ll know that the gut microbiome consists of a wide variety of bacteria and its specific composition is unique to each person. The colon contains billions of bacteria with over 500 different species.

Research has shown that certain strains seem to be more effective than others for treating different conditions, from cognitive performance to digestive ailments including Irritable Bowel Syndrome (IBS). You're therefore more likely to experience good results by taking probiotics that have been shown to achieve specific effects you’re searching for or combat the potential negative effects, such as antibiotic usage.

Additionally, it's important to consume probiotics in sufficient amounts. Probiotics are generally measured in colony-forming units (CFU) with higher doses producing the best results in most studies. There are certain probiotics, however, that may be effective at dosages of 1–2 billion CFU per day as opposed to others that may require at least 20 billion CFU to achieve the desired effects.

I recommend aiming for at least 20 billion CFU, except in cases of antibiotic usage or immunocompromised individuals where a higher dosage such as 90 billion may be necessary to re-colonise the gut. according to research, even higher doses of up to 1.8 trillion CFU have not been found to cause ill effects. However, higher CFU counts are more expensive and studies have not found such high counts to be necessarily more beneficial.

One of the most common questions I have received is "If humans have ben healthy without taking a probiotic supplement before, why are they so important now?" For one, our early ancestors used to have to ferment most of their food below ground in clay pots due to lack of refrigeration. This fermentation yielded whole-food supply of probiotics, which we still can and should follow. Since then, there have been vast cultural and agricultural changes that have had an impact on the gut microbiome. These include the advent and over-prescription of antibiotics; over-processing of native plants, such as corn; diets moving away from the higher intake of gut-healthy plant food; significant usage of herbicides and pesticides; and soil depletion of trace minerals, vitamins, and healthy bacteria; and even increased stress, which affects the bacterial balance in the gut through the gut-brain axis.

Probiotic supplementation, really in the form of food and secondarily in the form of pills, might help combat these effects. Unfortunately, the U.S. has no federal standards for probiotic supplements and the FDA doesn’t regulate this 30-billion dollar global industry. Therefore, there are many products without any guarantee of their advertised probiotic strains; that the strains are alive; or that they’re free from unhealthy ingredients such as wood pulp as a filler.

Therefore, it may be best to choose a brand-name probiotic that has research backing their effectiveness. You should look for:

  • Ensure that the product contains live strains of the bacteria and that the life of its strains is guaranteed at the time of use rather than at the time of manufacture.

  • A product that is gluten- and sugar-free, so as to avoid feeding the unhealthy bacteria.

  • Check for survivability through stomach acid. Most brands that employ acid-resistant delivery technology will advertise that on the bottle. Some keywords include pearl encapsulation, enteric coating, or variations of such. If you’re unsure, contact the company to inquire.

  • A highly-researched medical-grade probiotic is Visbiome, previously called VSL #3, which you can inquire about with your healthcare practitioner. It contains Lactobacillus, Bifidobacterium and Streptococcus strains and has a significantly high CFU count of 112.5 billion for regular strength and 900 Billion for the extra strength. For those who are recovering from or are still on an antibiotic protocol, are healing from intestinal damage, or immunocompromised, this might be a fitting investment. The regular strength is available for purchase on their site and the extra strength requires request for authorisation.

  • Look into investing in human-strain probiotics. Coconut Cult is a yoghurt that you can treat as a supplement by taking only a tablespoon per day. Although as a yogurt itself the price is extremely high at $14/jar, it is comparable or even cheaper than most probiotic supplements when treated as medicine.

  • Seed is one of the most technologically-advanced probiotic currently on the market. In addition to CFU, they test for Active Fluorescent Units (AFU), which is the most advanced and precise enumeration method to calculate a more precise measurement of all viable cells. You can shop them here.

Choosing the Right Probiotic Strains for Your Needs

Constipation and Diarrhea

A number of studies have shown that supplementing with certain probiotic strains can reduce constipation in both adults and children, such as here, here, and here. In a study comparing probiotics and prebiotics in children with IBS, B. lactis was shown to provide significant constipation relief. As a result of the supplementation, the probiotics group reported having experienced less belching, abdominal discomfort, and bloating following meals as opposed to the prebiotics group. It’s important to note here that prebiotics are the precursor fuel for probiotics of indigestible fibers. Although they are beneficial in supporting probiotics, they can cause discomfort in their indigestion with those who have sensitive digestive conditions such as IBS due to the fermentation of these fibers.

Other probiotics that may improve constipation include B. longumS. cerevisiae and a combination of L. acidophilusL. reuteriL. plantarumL. rhamnosus and B. animalis, according to the studies here, here, and hereAnother study found the additional strains of Lactobacillus rhamnosus GG and Lactobacillus bulgaricus to be effective.

For diarrhea, research suggests that certain probiotics seem to be especially effective for diarrhea-predominant IBS, including B. coagulans, S. boulardii and a combination of several Lactobacillus and Bifidobacterium strains. Some research can be found here, here, and here. These can be helpful for diarrhea as a result of antibiotic usage, since beneficial bacteria die off with the harmful bacteria that antibiotics target.

Additionally, B. longum is a potential strain that might aid in regularity as it’s one of the first types of bacteria to colonise our bodies at birth. This strain is responsible for fermenting sugars into lactic acid, helping to stabilise the acidity of the gastrointestinal tract and inhibiting growth of harmful bacteria. In one study following a group of adults prone to constipation, taking a mix of B. longum BB536 with milk or yogurt for two weeks increased bowel movements.

Vaginal Health

L. Acidophilus is the main beneficial bacteria that is one of the most widely recognised probiotics. This stain is able to survive stomach passage and are able to colonise in the intestine, amplifying further growth of beneficial bacteria. It has been shown to be effective in treating vaginal bacterial infections, reducing problems associated with lactose intolerance, and even decrease the risk of colon cancer.

Brain health

As previously mentioned, digestion and the brain are linked intricately through the gut-brain axis. There has even been growing research investigating the link between gut microbiome and cognitive disorders including Alzheimer’s Disease and Parkinson’s Disease.

Research suggests that the gut bacteria’s fermentation of fiber into short-chain fatty acids or SCFA may also benefit the brain and nervous system. Taking probiotic supplements also appears to help people struggling with depression, including those with major depressive disorder, according to this study and this one.

In one study of patients with major depression, those who took L. acidophilus, L. casei and B. bifidum had a significant decrease in reported depression. The research participants also showcased reductions in insulin levels and inflammatory markers.

B. longum is also one of the species researched for the role of probiotics in the gut-brain axis. A report from University College Cork found in a study of healthy men that supplementing with B. longum 1714 caused stress levels to decrease and memory to improve.

L. casei also may be potentially beneficial in relieving anxiety. One 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.

Heart Health

You might not be at an age or condition to be concerned about heart health, but it’s vital to be aware of your family history that might put you at risk. Additionally, high stress can increase cortisol levels which affect fat metabolism in the gastrointestinal tract and the liver to then increase bad cholesterol, which can damage heart health.

Specific bacterial strains that seem to be effective at lowering cholesterol levels include Lactobacillus acidophilusBifidobacterium longum and Lactobacillus reuteri. An analysis of 14 studies found that probiotics led to an average reduction in LDL cholesterol, a slight increase in HDL and a decrease in triglycerides. This might be due to the strains affecting the aforementioned fat metabolism and decreasing absorption of dietary cholesterol in the gut.


This study suggests that taking probiotic supplements may foster a balanced gut microbiome and thus cultivate a stronger immune system. Of particular note are the strains Lactobacillus GGLactobacillus crispatusLactobacillus gasseri, Bifidobacterium bifidum and Bifidobacterium longum. These strains appear to reduce the risk of respiratory illness and eczema in children, as well as urinary tract infections in adult women.

Skin Health

Streptococcus thermophilus is a strain that can support skin’s integrity. In one study, S. thermophilus was shown to have a beneficial effect on the level of ceramides in the barrier of the skin, which protects underlying tissue from infection, dehydration and chemicals.


About the Author

Almila Kakinc-Dodd is the Founder, Editor-in-Chief of The Thirlby. She is also the author of the book The Thirlby: A Field Guide to a Vibrant Mind, Body, & Soul. She is currently pursuing her Master’s in Nursing as a Dean’s Scholar at Johns Hopkins University. Her background is in Anthropology & Literature, which she has further enriched through her Integrative Health Practitioner training at Duke University. She lives in the Washington, D.C. Metro Area, where she regularly contributes to various publications. She is a member of Democratic Socialists of America and urges others to join the movement.

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