Probiotics for gut health: strains, CFUs and how to choose

Probiotics are live microorganisms, mostly friendly bacteria and one helpful yeast, that you can get from fermented foods or from a capsule. Choosing one gets much easier once you can read three things on the label: the strain names, the CFU count, and how it should be stored.

What probiotics are

Your gut is home to a huge community of microbes. Probiotics are the live microorganisms added to foods and supplements to join them. Most belong to two big families, Lactobacillus and Bifidobacterium, and a few products use a beneficial yeast called Saccharomyces boulardii or spore-forming bacteria instead.

Probiotic supplements temporarily modify gut flora and help support gastrointestinal health. Fermented foods like yogurt, kefir, sauerkraut and kimchi bring live cultures too, and many people like to have both in the mix.

How to read a probiotic label

Probiotic labels look busy, but they follow the same pattern. Here's what to look at, in order.

1. The strains. Each one has a genus, a species and often a strain code, like Lactobacillus rhamnosus GG. The code tells you exactly which bacterium you're getting, which is how studies and labels line up.
2. The CFU count. CFU stands for colony-forming units, the number of live organisms per capsule. Look for a count guaranteed "at expiry" rather than "at time of manufacture".
3. Storage. Some probiotics are shelf stable; others live in the fridge. Store yours the way the label says, at home and on the way home.
4. Extras. Check for added prebiotics (FOS, inulin, GOS), the capsule type, and allergens like milk, which some formulas use as a growing medium.

The probiotic families, decoded

Is a higher CFU better?

Not automatically. A higher count gives you more organisms per capsule, but the strains, the format and whether you'll keep taking it matter just as much. Everyday multi-strain probiotics often sit somewhere around 10 to 15 billion CFU per capsule, while higher-count formulas carry 50 billion or more for times when you want a bigger dose.

Pick the strains first, then the count, then the format you'll actually take every day.

Multi-strain or targeted?

Shelf stable or refrigerated?

Shelf-stable probiotics are made to keep their count at room temperature, so they suit travel, the office drawer and anyone who forgets what's in the fridge door. Others need the fridge. Neither is better; the storage line on the label tells you which, and we keep each one the way it should be kept in store.

The probiotics on our shelves

Our probiotic section runs from everyday multi-strain capsules to single-strain and yeast-based options. A few families ask about most, from Canadian brands CanPrev, Cyto-Matrix, AOR and Natural Factors:

For a bifidobacteria-focused option, NFH Bifido SAP is built around Bifidobacterium strains. Whole Earth & Sea grows its ten strains on natural foods rather than dairy and adds a fermented fruit and vegetable blend. If you'd like a yeast-based probiotic, Naka Saccharomyces Boulardii comes in delayed-release veggie capsules.

How to take a probiotic

1. Follow the label. Some probiotics are best with food, others on an empty stomach. The directions tell you which.
2. Be consistent. Probiotics work while you take them, so a daily habit matters more than the perfect time of day.
3. Space them from antibiotics. If you're on antibiotics, take your probiotic a few hours apart from them, unless your probiotic is a yeast like S. boulardii.
4. Add fibre and fermented foods. Vegetables, beans, whole grains and live-culture foods round out a gut-friendly routine.

Probiotic foods worth keeping in the fridge

If you'd rather start with food, live-culture yogurt and kefir are the easy wins. Our kefir and yogurt guide covers the dairies we stock, and you can make kefir at home with a starter.

Prebiotic sodas are another way people add fibre to the day. Our prebiotic soda guide compares Poppi, Cove and more.

Questions we get a lot

What is the best probiotic for gut health?

There isn't one best for everyone. A well-labelled multi-strain probiotic with a count guaranteed at expiry is a sensible everyday starting point. From there, people choose by strain, storage and format.

Are probiotics good for gut health?

Probiotics help support gastrointestinal health and temporarily modify gut flora while you take them. Many people find a daily probiotic, plus fibre and fermented foods, an easy part of their routine.

When is the best time to take a probiotic?

Follow the label: some are made to be taken with a meal and others on an empty stomach. Beyond that, the best time is the one you'll remember every day.

Do probiotics need to be refrigerated?

Only some. Shelf-stable probiotics keep at room temperature; others need the fridge. The storage line on the label tells you which.

Can I take probiotics with my other supplements?

Generally, yes. The main one to space out is antibiotics, which can affect probiotic bacteria. Digestive enzymes and probiotics are often taken together.

What about men's and women's probiotics?

Formulas made for women or men choose strains and counts with each group in mind. We carry several, including Naka Platinum, Renew Life and Metagenics. Ask us to compare them side by side.

Probiotics are in the supplement aisle at both stores: 486 Starboard Drive in Bedford and 590 Portland Street in Dartmouth, open seven days. Refrigerated probiotics are kept cold in store, and for kids, see our probiotics for kids and babies guide. In HRM, order by 11 am with Luminate Express for same-day delivery, or choose pickup. Anywhere else in Canada, orders over $80 ship free.

Sources: International Scientific Association for Probiotics and Prebiotics, consumer resources; NIH Office of Dietary Supplements, Probiotics; product labels and listings. This article is general information, not medical advice.