Probiotics: The good bacteria

What are probiotics?

Digestive health relies upon a complex community of bacteria and other live microorganisms, also known as gut flora, or the microbiota. They help to maintain balance in our digestive system by aiding in digestion, metabolism and controlling levels of harmful bacteria. Changes in the gut microbiota have been associated with various health concerns. Probiotics are 'good bacteria' that we ingest to help provide balance in the digestive system1.

How do probiotics work?

Probiotics have been shown to have many important functions in the digestive tract. Probiotics:


Feed on and ferment the fibres in the gut. This helps generate food and energy for the cells lining the lower digestive tract1.


Build up the mucosal lining of the digestive tract. This helps defend against toxins coming into the body1.


Lower the acidity within the digestive tract. This minimises growth of harmful bacteria that might generate in the gut2.


Compete against harmful bacterial for space within the gut. This reduces the ability of harmful bacteria to take hold and cause harm2.

Who may benefit from probiotics?


Probiotics may be beneficial for people who need:

  • Help managing digestive symptoms, such as constipation3.
  • To restore “good bacteria” when taking antibiotics1

There is a lot of research going into the area of gut flora, and there are a growing number of studies into links between gut microflora and many health conditions.

Some studies suggest that a low FODMAP diet could lead to depletion of bifidobacteria (a good bacteria) concentrations in the gut in people with irritable bowel syndrome. A recent study where people with IBS were placed on a low FODMAP diet and given a probiotic supplement for 4 weeks, found that the FODMAP diet provided relief from symptoms, while supplementation with the probiotic restored levels of bifidobacterium in the gut4.

Make sure that you read labels for the clinical effectiveness of a probiotic. If you need to, consult a healthcare professional.

Measuring 'good bacteria'

The quantity of bacteria in probiotic supplements is measured in Colony Forming Units (CFU), or the number of live bacteria in one serving. These counts are usually in the millions or billions. CFUs in foods with probiotics are variable, and are generally not listed on food labels. In general, probiotic supplements offer far larger doses, and are labelled with information about how well they work and live CFU counts for specific conditions.


Choosing the right probiotic for you

There are so many different probiotic options on the market that it can be hard to know which one is right for you. All probiotics may support the digestive system, though some strains have a larger body of clinical evidence to support other roles in the body and the benefits they may provide. Read the labels, looking for the following information:

clinically proven

Clinically tested: An effective probiotic strain is one that has been shown to deliver the health benefit of interest (for example, to help regularity) in a well-controlled clinical study.

bacteria cluster

Higher vs. lower CFU count? It might seem obvious to aim for the product with the highest CFU count, but this may not lead you to the better-quality product. What is important to understand, is what has been clinically studied and proven. For example, if a clinical study was done with a probiotic containing 1 billion live cultures, its effectiveness has been measured at that level (potency) and not necessarily more or less. Taking an amount greater than what shows a benefit in clinical studies would not necessarily provide any additional benefit3.


Additives: Some probiotics may contain additives such as inulin, FOS, chicory root or lactose which are high in FODMAPs. These may cause adverse symptoms in some people. It is important to carefully read all labels in order to understand the ingredients that may be added. Always check with your healthcare professional to ensure that the probiotic is low FODMAP.


Multiple vs. single strain probiotics: Keep in mind when selecting a probiotic whether the particular strain or mix of strains have been shown to deliver the health benefit of interest in a well-controlled study. It is best to only consider multiple strain probiotics if benefits have been shown in clinical trials.


Refrigerated vs. shelf-stable supplements: Both shelf stable and refrigerated probiotics are now commonly available and can be equally as effective. Certain strains are shelf stable at room temperature and certain strains need to be refrigerated, so decide which one is convenient for you. Make sure you store probiotic products in accordance with the label instructions.

Are probiotics high FODMAP?

Probiotic ingredients themselves do not contain FODMAPs. However, some probiotic supplements contain additives or other ingredients like inulin, FOS, chicory root or lactose, which are high FODMAP. It is important to carefully read all labels to understand the ingredients that may be added. One low FODMAP probiotic available is ProNourish® Regularity & Balance Probiotic.

1Jandhyala et al. World J Gastroenterol 2015

2Butel et al. Médecine et maladies infectieuses 2014

3Eskesen D et al. Br J Nutr 2015;114(10):1638–46

4Staudacher HM et al. Gastroenterology 2017;153(4):936–947