How to choose a quality probiotic - Part 2: Efficacy


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Choosing a Quality Probiotic – Part 2: Efficacy

BY Lucy Taylor September 12, 2019

In part 1 of Choosing a Quality Probiotic, we explored probiotic product stability, which is important to ensure that the product will contain the number of live bacteria stated on the label. If you haven’t already read that post, I’d suggest going back and reading it first. In this post, we’re going to take a look at probiotic efficacy, which essentially just means whether the product is able to do what it says it can on the label.

Choosing a Quality Probiotic - Activated Probiotics

Most probiotic products list one or more health claims on their label, ranging from general claims, such as ‘maintains healthy digestion’, to more specific claims, such as ‘helps reduce the occurrence of common colds’. In order to make these claims in Australia, the manufacturer of the product is required to have evidence to support these claims.

So, the first thing you need to consider when choosing a probiotic product is which aspect of your health you are seeking to improve. For example, if you’re particularly susceptible to catching colds through winter, it would make sense to choose a product which makes specific claims about supporting immune system function and reducing the occurrence of common colds.

The first thing you need to consider when choosing a probiotic product is which aspect of your health you are seeking to improve

Once you’ve narrowed down which health benefit you’re looking for from a probiotic product, it’s important to choose products containing probiotic strains that have been clinically trialed, and found to be more effective than placebo for a specific health outcome. For example, if you’re looking for a probiotic to help manage the symptoms of Irritable Bowel Syndrome (IBS), it would be reasonable to take a product containing probiotic strains that a) have been given to people who suffer from IBS, and b) significantly reduced their symptoms, compared to an inactive placebo.

On this point, the manufacturer of the product should disclose which probiotic strain/s are in the product, as different strains of bacteria – even within the same species - can have very different effects in the body.

Looking at the probiotic strain Lactobacillus Plantarum 299v as an example, the genus (or broad group) the bacteria belong to is ‘Lactobacillus’, the species is ‘Plantarum’, and the strain is ‘299v’. Further, the manufacturer should also provide the unique strain identifier code, which is ‘DSM 9843’ for Lactobacillus Plantarum 299v. This specific strain - Lactobacillus Plantarum 299v DSM 9843- has been clinically trialed in people with IBS, and found to be significantly better than placebo for reducing the symptoms (1).

If a manufacturer lists the probiotic species only, without the strain name and identifier code (i.e. ‘Lactobacillus plantarum’), you can’t be sure which strain is in the product, and whether it has been clinically trialed. While these ‘generic’ probiotic products are generally cheaper, they cannot guarantee a specific health benefit.

Finally, the product you are taking should contain the same number of live bacteria that was found to be beneficial in the clinical trial process, which is referred to as the ‘therapeutic dose’.
The therapeutic dose depends on the specific probiotic strain; some are beneficial at a dose of just one billion live bacteria, while other strains require over 10 billion live bacteria.

For example, the therapeutic dose of Lactobacillus Plantarum 299v (DSM 9843) for reducing the symptoms of IBS is 10 billion live bacteria (1), whereas a daily dose of just one billion live bacteria of Lactobacillus Plantarum HEAL 9 (DSM 15312) and Lactobacillus paracasei 8700:2 (DSM 13434) has been shown to help reduce the frequency, duration and symptoms of common colds (2)(3).

As you can see, there is no one-size-fits-all approach to supplementing with probiotics, and products with greater numbers of live bacteria aren’t necessarily any more beneficial than those with lower doses – it all comes down to what has been proven to have the most benefit, through clinical trials.


  1. Ducrotté P, Sawant P, Jayanthi V. Clinical trial: Lactobacillus plantarum 299v (DSM 9843) improves symptoms of irritable bowel syndrome. World J Gastroenterol. 2012 Aug 14;18(30):4012–8.
  2. Berggren A, Lazou Ahrén I, Larsson N, Önning G. Randomised, double-blind and placebo-controlled study using new probiotic lactobacilli for strengthening the body immune defence against viral infections. European Journal of Nutrition. 2011 Apr;50(3):203–10.
  3. Busch R, Gruenwald J, Dudek S. Randomized, Double Blind and Placebo Controlled Study Using a Combination of Two Probiotic Lactobacilli to Alleviate Symptoms and Frequency of Common Cold. Food and Nutrition Sciences. 2013;04(11):13–20.




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