For a probiotic to have reliable, therapeutic results, it must fulfill ALL of the six criteria listed to below to ensure safety, potency and bioavailability:

1. Manufactured in a cGMP Facility and stored in dark, glass bottles only

Make sure the probiotic is manufactured in a facility that carries the cGMP (current Good Manufacturing Practices) certification, otherwise you risk consuming a contaminated product. Contaminants could consist of lead, mercury (and other poisonous heavy metals), and undesirable bacteria. A 1990 independent laboratory study found that nine out of ten brands of popular Lactobacillus acidophilus probiotics actually contained no acidophilus at all. All nine contained contaminants and other species of lactobacilli instead. Probiotics are also sensitive to (and damaged by) light and moisture. Only a glass bottle will keep out all moisture – all plastic is permeable to varying degrees of moisture. In addition, the glass must be dark (or amber colored) to keep out light, which also damages bacteria.

2. Different species must not be touching each other

Different species of bacteria placed together will compete for space and try to dominate each other, resulting in competitive exclusion by the dominant species. In vitro studies have shown that when you place different species together, the dominant (strongest) species will usually produce bacteriocins that kill closely related species.(1)

Therefore, each species (eg. acidophilus, bifidum, bulgaricus) must be kept in its own bottle or in separate capsules. Refrigeration does not prevent this from happening either, since certain bacteriocins have proved stable at temperatures as low as -20 degrees Celcius. I know most probiotic manufacturers sell regular capsules or powders with anywhere from 3 to 14 different species packaged together in one jar, or one capsule. Again, I’m absolutely mystified as to why they do this. However, check the bottle and you’ll see that none of these manufacturers guarantees the number of live, viable bacteria in their product at the time of opening, or consumption. Nor do they guarantee how many of each species and strain remains alive and viable for effective colonization in the gut at time of consumption. See Quality Concerns below.

3. Probiotics must be kept refrigerated at all times

The bacteria need to be stored in a fridge at the store and they must also be shipped in refrigerated trucks to the store. Heat quickly kills bacteria and even at room temperature they will become active and soon live out their life cycle – think of what happens if you leave yoghurt on the counter. The best way to preserve bacterial potency is by keeping it cold at all times, until you’re ready to ingest it. Freeze drying is the best method of preserving the bacteria and for this to be maintained, they must be kept very cold at all times until you’re ready to ingest them. Of course, keep your probiotics refrigerated at home too.

4. Strain and number of bacteria per serving must be listed on the bottle

Only certain strains of bacteria are potent and effective (eg. L. bulgaricus DDS-14 is excellent, L. bulgaricus DDS-13 is useless – remember, ‘bulgaricus’ is the species, ‘DDS-14’ is the strain). If the manufacturer just lists ‘acidophilus’ for example, chances are they’ve used a cheap and ineffective strain of L. acidophilus. There are approximately 200 identified strains of L. acidophilus, of these, only 13 have good antibiotic (against bad bacteria) qualities, thus, the strain is indeed very important. They must also list the number of bacteria guaranteed per serving (and this should be between 2-5 billion colony forming units per serving) at the time of opening. This guarantee is key: If a manufacturer only guarantees the number of bacteria at the time of manufacture, this is meaningless. At manufacture, a bottle may contain 2 billion cfu (colony forming units) per serving – however, by the time that bottle gets to you, the bacteria may be mostly dead. Another trick to watch out for is that manufacturers will list (for example) two different strains of L. acidophilus, one of which is a good strain and the other a cheap useless one. Then they will list the total guaranteed bacteria per serving at 2 billion cfu. However, they haven’t told you how much of that total count is the effective strain and how much is the ineffective one. It’s also a good idea to use human strains (vs. bovine or porcine strains) for safety’s sake.

5. Freeze-dried is best

In ultrafiltration extraction methods, the bacteria are pressed through a filter that removes the larger molecules of their growth medium. However, when bacteria are growing in their culture, they form into chains as they multiply. Ultrafiltration results in the breakup of these chains, separates the bacteria from their beneficial growth medium (supernatant) and can also damage the bacteria themselves. The best method of preserving bacteria (and the most expensive) is to freeze dry it along with its growth medium. Many scientists maintain it’s best to consume bacteria along with it’s growth medium (also known as the substrate or supernatant) since this protects the bacteria from stomach acid and provides a ready food source for the bacteria to consume as they establish themselves in your gastrointestinal tract. Also, as the bacteria grow in the culture (of milk or vegetable matter), the growth and culturing process produces valuable substances such as vitamins, antioxidants, immune system factors, antimicrobial compounds and digestive enzymes that greatly benefit your body when ingested. Ideally, purchase bacteria that is freeze dried along with its growth medium.

6. Avoid prebiotics

Some companies package their probiotics with fructooligosaccharides (FOS) and/or inulin – indigestible substances referred to as prebiotics, which they claim feed the bacteria, thereby improving performance. Keep in mind though, that many bacteria (both good and bad) can feed on these substances. So if you have a predominantly bad bacterial flora (as most, if not all people with IBD do) consuming prebiotics may exacerbate your symptoms. Also, most FOS is manufactured via chemical synthesis and in many instances has been shown to cause abdominal pain, bloating and gas. I especially don’t recommend it for people with IBS or IBD. Also avoid FOS and inulin in vitamin/mineral supplements, whey protein powders, etc. Be sure to read labels as it’s become popular to add it to all kinds of products. For perfectly healthy people with an established good bacterial flora, prebiotics are probably okay, especially if they are not able to obtain these substances naturally through a good diet.

If you’ve read any of my books, you’ll know that the only probiotics I’ve found so far that meet all of these selection criteria are Natren brand. And I’m also a big fan of making your own yoghurt using Natren’s Yoghurt Starter and lacto-fermenting veggies – to get ongoing food-source probiotics in your diet.

Health Canada put out a pretty good discussion paper on probiotics, which addressed some of these concerns about most probiotics not being manufactured or stored properly to ensure potency. Here are just a few highlights from that paper:

Impact of processing, environment and diet on probiotic bacteria

“Probiotics in NHPs [natural health products] and foods are fragile and particularly sensitive to processing conditions (such as freezing, drying, exposure to oxygen) and to storage conditions (such as room temperature, oxygen, moisture).”

Quality Concerns

“A significant quality issue for probiotic supplements is the viability of bacteria in the product, specifically how many organisms are alive when the consumer purchases it as many products claim only the amount at the time of manufacture. As well, the product should contain the bacterial species that it claims on the label, and potentially pathogenic microorganisms should not be present.

A recent Canadian study assessed whether commercially prepared probiotic products contained viable organisms, as claimed by the manufacturers, and particularly whether products labeled as containing Lactobacillus did so.(2) An additional objective of the research was to identify and quantify as many species as feasible and to compare them with the contents listed on labels. The design was randomized, double-blind trial of 10 brands of probiotic preparations bought over-the-counter in British Columbia ‘s lower mainland. Only products claiming to contain Lactobacillus were included in the study. The study measured the viable organisms in each probiotic brand and quantities of Lactobacillus in each product.

The results showed that none of the 10 products tested matched their labeled microbiologic specifications and two brands grew nothing aerobically or anaerobically. No Lactobacillus grew in five brands, although their labels stated that this was the main species. Eight brands contained viable cells, but only 10% of the number stated by their manufacturers. Most product labels did not adequately identify or quantify microbes which led the author to conclude that the use of probiotics should not be recommended at this time.

In research conducted by a media outlet and broadcasted in 2003(3), two different probiotic capsules were each tested twice, including newly stocked retail product to determine the number of live bacteria and secondly near the end of the product’s shelf life to test if the counts had fallen. The first label claimed 6 billion live cultures per capsule but testing showed only 1.7 billion and within two weeks, millions more bacteria died, with 460 million still alive. The second product did contain the label claim of more than one billion in the first test. But on the follow-up test, 692 million bacteria remained alive.

Dr. Gregor Reid, director, Canadian Research and Development Centre for Probiotics, Lawson Health Research Institute, and professor of Microbiology and Immunology, University of Western Ontario , London was quoted on the program as stating “This is particularly disheartening, as you’re getting a massive drop in viability, even within two weeks. You’ve picked two products but you could have picked 10 or 15 and, according to European studies, you’d find the same kind of results where you get a drop off in viability.”

Research has further shown that products should contain between one million and one billion live bacteria to be efficacious.(4) The media program concluded by stating that ” … manufacturers can say whatever they want on those containers. That’s because there are no Canadian government regulations on how much live bacteria there should be, and no rules on what labels have to tell us about quantity”.”


(1) “Lactobacillus and bifidobacterium in irritable bowel syndrome: Symptom responses and relationship to cytokine profiles” by Liam O’Mahony et al. Gastroenterology March 2005;128:541-551,783-785

(2) Huff, B.A. 2004. Caveat emptor. “Probiotics” might not be what they seem. Can. Fam. Physician. Apr. 50:583-7.

(3) CBC MARKETPLACE: PROBIOTICS. Testing bacteria levels. September 9, 2003. files/food/yogurt/

(4) Reid G, Jass J, Sebulsky MT , McCormick JK. 2003. Potential uses of probiotics in clinical practice. Clin. Microbiol. Rev. 16:658-672.

How To Choose A Potent Probiotic

20 thoughts on “How To Choose A Potent Probiotic

  • Hi Jini,

    Please comment on this brand of Probiotics.
    “Syntol AMD” by Arthur Andrew Medical.
    Being in the spore form does it have any benefits.

    Thank you!!

  • I just happened to purchase HMF Forte from Genestra by chance.
    Any comment on this particular brand ?
    I will probably try the Natren one going forward.

    1. Hello Ahmed,

      Thank you for your question. We do not have any experience with that particular probiotic brand. However, through extensive research Natren is the only brand Jini has found that she trusts and would recommend. As stated in this article why. If you have any other questions please let us know.

      Kind Regards,
      Customer Care

  • Hi,

    What are your thoughts on using the natren bifido probiotic having a j-pouch and no large intestine? I’m unsure whether or not they will be lost in transit.

    1. Hello Lauren,

      Thank you for the inquiry. The Bifido probiotic is most beneficial for the large intestine, but is as well for the rest of the body. If cost is not a concern for you it may still be worth using. However, if you are concerned on cost the other probiotics may be of more use to you can the Bifido. Please let us know if you have any other questions.

      Kind Regards,
      Customer Care

  • Just a quick question, I noticed it states above that different strains must be kept separate, so I was a bit confused to see the site recommended the Healthy Trinity bottle that seems to have 3 strains in one bottle, are they somehow ok together in this particular formula, and if so how do they achieve that? Also are any of these Natren probiotics enteric coated, or do they somehow have a similar action that prevents the stomach from destroying them before they reach the intestines?

    And Thanks so much for the quick reply to my earlier question today!


    1. Hello Jon,

      Those are great questions. Here are your answers straight from the Natren company.
      “The powder products are protected with the intrinsic supernatant, part of the original nourishing and protective culture medium, which provides a natural buffer against gastric acid.

      Micro-enrobing with a unique oil matrix is the best way to protect probiotic bacteria from stomach acid. Natren Healthy Trinity® is the first to introduce a micro-enrobing, unique delivery system – a hard gel capsule in which three super strains of probiotic bacteria are suspended in sunflower oil and vitamin E to keep the bacteria separate, noncompetitive and protected from gastric digestive juices for optimum absorption.

      The bacteria strains must be bile-resistant. All Natren probiotics have laboratory-tested bile-resistant strains which will survive bile salts.”

      Hope that helps clarify their probiotics for you. If you have any other questions please let us know.

      Kind Regards,
      Customer Care

  • Hi Jini,

    I started using the Natren megadophilus for my daughter. She has CD. She seems to have a lot of gas and diarrhea on it. Do you recommend still using it? She’s also on prednisone and Imuran.


    1. Hi Betsy,

      We can’t comment on the prescription medication you mentioned as we are not qualified to do so. Whether or not your daughter is on a regimen of wild oregano oil and probiotics as outlined in Jini’s wild oregano protocol, she might be experiencing a die off effect as those symptoms aren’t uncommon. You may want to switch to the Bifido Factor instead as that’s the one Jini recommends that people use who want to take a cautious approach (more details on p.175 of her Listen to Your Gut book) and then gradually add the Megadophilus + Digesta-Lac.

      Kind regards,
      Customer Care

  • Hi Jini,

    I live in Europe and the cost of Natren probiotics + shipping is not affordable for me. I’ve looked around for probiotics manufactured in Europe but all of them contain at least 2 different species in one capsule. The supposedly best ones (and most expensive ones) even contain 10 to 12 different species!

    What should I do? Not buy any probiotic or buy one of the probiotics we find in Europe? And if so based on which criteria should I choose them because none of them fit the standards written above.

    PS: some of them guarantee however that the bacterias are gonna be alive until expiration date. So I’m a bit confused now…

    Thank you!

    1. Hi Jay,

      Homemade yoghurt contains a good level of probiotics. It also contains live enzymes which help with digestion. So this is the best way to improve your gut microbiota if you cannot take Natren probiotics. Check out Jini’s Homemade Yogurt Recipes below:

      How To Make Homemade Yoghurt Using Probiotic Cultures
      Make Yogurt: Natren’s Authentic Bulgarian Style Yogurt Starter Culture

      Thanks for your comment and let me know if you have any additional questions.

      Kind Regards,
      Cris B
      Customer Care

  • Hi Jini,
    I am wondering whether Natren has only three strains of probiotic. A lot of probiotic brands say they have 13 strains of probiotics, as we need a variety of probiotic strains. Can you explain?
    thank you

    1. Hi Kyoungwon,

      Thank you for your comment! Jini has recently been discussing probiotics with Natren founder, Natasha Trenev, and addresses your question as well as many other topics. Each single strain can help with specific symptoms as described in Jini’s Microbiome blog/video. You can watch her Q&A videos by clicking on the links below:

      Kind regards,
      Customer Care

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