Suboptimal gut flora opens the door for unfriendly microbes to step in and disrupt balance. One targeted strategy to help restore and promote gut balance is probiotics – but when it comes to this supplement, it’s important to choose the best option for your body.

Among probiotics’ numerous health benefits, research shows these friendly microorganisms support a healthy bowel and immune system; promote a healthy gut and regularity during travel; help you maintain a healthy weight, support healthy skin, ease bloating, and help to reduce the effects of stress.

Think of probiotics as your little helpers that restore order and help maintain harmony in your gut ecosystem. You want them to outnumber and antagonise the unwelcome bugs, including unfavourable bacteria, yeast, and parasites.

Probiotic bacteria actually compete against unfriendly flora for bacterial binding sites on the inside lining of your intestines, further protecting you.

One way to populate your gut with probiotics, to promote or restore harmony and get all their many benefits, is with the right foods, which support the growth and proliferation of the good bacteria that crowd out the bad ones.

These include cultured foods (such as yogurts or kefir); fermented foods like sauerkraut, miso, pickled vegetables, and kimchi; and cultured beverages, like kombucha—that all contain favourable live bacteria.

Bifido-What? Understanding Probiotic Species

You’ll find probiotic supplements that contain freeze-dried bacteria in capsules, tablets, and powders. That’s the easy part: Turn the label around and you’ll see a list of unpronounceable ingredients .. it can be very baffling.

While there are virtually endless species of beneficial bacteria, the ones you’ll most commonly find in probiotic supplements are LactobacillusBifidobacterium, and Saccharomyces boulardii (which is actually a favourable, non-colonising yeast, not a bacteria).

Among these three genera (or families) are specific species. Lactobacillus, for instance, includes the individual species L. acidophilus, L. rhamnosus, L. bulgaricus, L. reuteri, and L. casei. The most common Bifidobacterium species include B. animalis, B. infantis, B. lactis, and B. longum. And at an ever more granular level, there are unique strains (e.g., L. acidophilus NCFM, B. lactis Bi-07, etc.). Let’s look at the benefits of these three families—LactobacillusBifidobacterium, and Saccharomyces—more closely:


Lactobacillus bacteria predominantly live in your small bowel (the portion of your gut that follows the stomach). Probiotics that contain Lactobacillus species help to repopulate the small intestine with these friendly organisms that aid in supporting digestion and immune function. The most beneficial species are L. acidophilus, L. plantarum, and L. paracasei.

A preclinical study found Lactobacillus acidophilus supported the inflammatory response in the gut.* L. rhamnosus helps increase GABA expression (an inhibitory neurotransmitter that helps you feel relaxed) in the brain, resulting in lower stress-related behaviour. Another found that a combination of Lactobacillus and Bifidobacteria  improved bloating, and yet another found that when individuals took the Lactobacillus rhamnosus GG strain, it helped protect normal bowel movement function and buffer from loose stools associated with antibiotic use.


The Bifidobacteria (Bifidus) bacteria predominantly live in your colon or large intestine. They produce the very important short-chain fatty acid butyrate, which supplies energy to your colon cells to keep them functioning optimally. But butyrate is also absorbed by the body, where it regulates a variety of metabolic processes, including your sensitivity to the hormone insulin (which regulates your blood sugar) and even memory formation in the brain.

The most beneficial of the Bifidobacteria are B. lactis and B. longum. One study showed that a specific strain (B420) of Bifidobacterium lactis helped control body fat mass, waist circumference, and food intake.


Saccharomyces is a friendly yeast that I often consider for people who have been on antibiotics. This yeast promotes the health of the intestinal lining, helping support healthy tight junctions and protect you from gut microbial imbalance. S. boulardii can also outcompete other unfriendly yeast that is cohabitating in the gut.

If that sounds confusing, don’t worry. With the following three strategies, you don’t need to remember those names to choose the right probiotic supplement.

How To Tell If Probiotics Are High Quality

Buying a probiotic supplement is something you don’t want to skimp on. Warehouse stores are great to buy paper towels and grass-fed beef in bulk, but those mega-containers of probiotics are hardly the great deal they might seem.

Quality matters for any supplement, and that goes triple for probiotics.

Many commercial brands lack the technology to identify specific strains and how much of that strain each dose contains. That could mean you get an ineffective or potentially harmful dose.

It’s a great sign if the company is using probiotic strains that have been used specifically in clinical trials at a dose similar to or the same as that used in the study.

This is one of the only ways to guarantee a probiotic’s effectiveness.

And even then, with probiotics, it’s all about survival. These delicate microorganisms must survive several obstacles—the manufacturing process, packaging, shelf life, and (once you take them) the acid in your stomach environment—to reach your intestines, where they do their job.

Keep in mind that when supplements contain a specific number of organisms, this number has an expiry eventually.

Probiotics are living organisms and can die, especially if that supplement sits on the shelf or in a shipping truck for a long time – or at elevated temperatures. Companies have to produce probiotics with a higher CFU (colony-forming unit) count in each capsule in order to guarantee the label potency through to the expiration date, or in the case of probiotics with a manufacturing date, for two years from that.

Unfortunately, many commercial brands don’t measure up. They are unstable in stomach acid. To avoid those and other problems, I strongly recommend buying a professional brand from a reputable health care professional or another vendor who stands by their products and submits their products for multiple rounds of quality testing, from raw ingredients to finished product. Some of these brands have created advanced technology that preserves a probiotic supplement’s survival on the shelf and in your gut.

How To Choose The Best Probiotic Supplement

If you do choose a commercial probiotic supplement, or if you’re curious about the brand your health care professional recommends or sells, then here are some things to consider:

Billions Is Better

Millions sounds like a lot, but not with probiotic supplements. You want a probiotic dose that contains billions of organisms.

A probiotic dose can range widely from 5 to 100 billion colony-forming units (CFUs), the measure used to express its potency. The range is due to number of strains (more strains, higher total CFU), and those doses should be at or higher than the doses used in the strain-specific research studies. Start low and increase as you can tolerate it.

Diversity Is Your Nest Friend

Your gut is diverse, so your probiotic should be too. Look for a supplement that contains multiple strains. This is sometimes listed as a proprietary blend, although with blends, you lose the transparency of knowing how many CFU each strain contributes. Inferior brands might contain only one probiotic species such as Lactobacillus acidophilus. Look for the beneficial strains of Lactobacillus and Bifidobacterium, and you may also see species like Streptococcus thermophilus and Saccharomyces boulardii, among others.

Go For Dairy-Free

Ideally, look for a dairy-free probiotic supplement that contains the clinically studied CFU dose of each of Lactobacillus and Bifidobacterium strains (this typically means at least a total of 30 billion CFUs) with information about manufacturing date or expiration.

Watch Out For Certain Binders And Fillers

Read the other ingredients on the label. Some commercial probiotic supplements contain undesirable binders and fillers, including lactose or cornstarch that may cause unpleasant effects, like gas and bloating, if you are sensitive to these ingredients.

Make Sure Your Probiotics Don’t Go Bad

Always look for the manufacturing date or expiration date, after which the potency on the bottle can no longer be guaranteed.

Most probiotics are good for two years from the manufacturing date, but ask the manufacturer if that information is not clear on their website.

Many high-quality shelf-stable probiotics exist. These do not require refrigeration. Other formulations do. The label should tell you specifically whether or not to refrigerate.

How To Find The Right Probiotic Dose

If you’re most interested in taking a probiotic supplement for overall gut health, I suggest starting with at least 30 billion CFUs.

Take your chosen probiotic on an empty stomach once or twice a day for at least three months.

After that time, reassess and decide if the benefits you achieved warrant continuing or maintaining over the long-term.

If you have chronic GI concerns, I strongly suggest working with a functional medicine doctor or other qualified health care professional who can partner with you and personalise your probiotic approach.

Potential Side Effects Of Probiotics

You’ll be happy to know that generally, probiotic supplements cause no significant side effects, other than the intended improvement to your gut health. However, probiotics can be tricky. Not every probiotic is right for each person. Sometimes it’s about finding the right fit. For example, signs that a probiotic might not be right for you include:

  • Bloating after taking it
  • Irregularity issues that resolve when you stop it
  • Irritability that increases when you take the probiotic

If this happens, then it’s time to consider switching to a new probiotic. Other reasons a probiotic might not be the right fit: certain GI conditions (e.g., SIBO or Candida). If you have either of these conditions, then definitely work with your doctors, because certain probiotic strains can potentially make your issues worse. Remember, if you think a probiotic is not helping, then seek advice to help you navigate the choices out there.