Dietitian Nicole Dynan, @the.guthealthdietitian, looks at what probiotic supplements are and if they are necessary

There’s been a lot of discussion emerging about probiotic supplements. Should dietitians be advising patients to add such supplements to their diets?

The short answer is, when deciding on probiotic supplements versus food, clinicians need to look at the individual patient. If there are no published efficacy studies on a probiotic, but it seems to help, it is a personal choice to continue or not.

What we do know is that the potential benefits of probiotics are promising – whether from food, drink or supplement. Probiotics are live bacteria that are naturally found in the gut, as well as in select foods and supplements. When taken in adequate amounts, they provide a health benefit to the patient.


Here’s more background on probiotics, to help you provide an informed response to patients:

What do probiotics do?

Probiotics rarely colonize in the gut, but rather interact with resident microbes. As they pass through the gut, they interact with gut cells, immune cells and food substances, exerting their benefits. Research has shown that probiotics can support digestive health and immune function, including: reducing antibiotic‐associated diarrhoea; improving resilience to infections; and improving digestion of lactose. Other benefits include reducing the risk of eczema and colic in infants, as well as necrotizing enterocolitis [1]. There is some early evidence of benefits in managing weight and glycaemic control, depression and anxiety [2] [3].

Are probiotics safe?

Probiotic foods and supplements have been determined to be safe for use in the general healthy population at recommended doses [1].

How do you choose a good probiotic product?

Not all probiotics are the same, and not all confer the same benefit to different patients. Most are from the genera Lactobacillus or Bifidobacterium or yeast. It is best to find a product containing the strain(s) that have demonstrated the best evidence for the benefit you are seeking [1].

Are probiotics best acquired via food or supplement?

It is early days in probiotic supplementation, and whilst there is some emerging evidence, more work needs to be done. Pros and cons of probiotic supplements should be considered for each patient [4].

What are the Pros and Cons?


  • Some strains have a clinical impact in some disorders, such as IBD and immunity post-antibiotic treatment (e.g. VSL#3) [5] [6]
  • They are well tolerated and provide bacterial diversity, and most provide high amounts of Colony Forming Units (CFU – the number of viable bacteria in sample serve) [4]


  • Technological advances are needed before we see a boost in effectiveness [4]
  • High doses can result in symptoms such as gas, bloating, constipation or diarrhoea [4]
  • Benefits of fermented foods may go beyond the strains of bacteria — e.g., the bioavailability of some vitamins and minerals is elevated by the fermentation process of vegetables [4]

What is the effective minimum dose?

A product with a larger dose or more strains is not always better. The best dose is one that demonstrates benefits in humans, which typically ranges from 100 million a trillion CFU per day [1].

Are fermented foods a good source of probiotics?

Although fermented foods are made with live cultures, they cannot automatically be deemed a “probiotic” unless the strains contained have been studied and shown to confer a health benefit [1].

Fermented foods high in “good” bacteria include:

  • Yoghurt with live cultures – look for 1 billion probiotics per serve 1 x 10(9) CFU
  • Kefir (fermented milk or water-based drink) – usually has 30 beneficial strains of good bacteria
  • Fresh kimchi (Korean fermented vegetables)
  • Fresh sauerkraut (fermented cabbage)

Eating a variety of these foods can help cultivate a variety of good bacteria. Look for words such as “live”, “active”, “raw” or “unpasteurised” on packaging to ensure that the manufacturing process hasn’t killed the probiotic strains. Some manufacturers of pasteurised products will add back probiotic strains to the final product. These will be listed in the ingredients [7].

Studies have shown that the benefits of these probiotic foods are only seen whilst being consumed [7].


Bottom line

  • When deciding on probiotic supplements versus food, clinicians need to look at the individual patient.
  • Whether from food, drink or supplement, the potential benefits of probiotics are promising.
  • If there are no published efficacy studies on a probiotic, but it seems to help, it is a personal choice to continue or not.


Additional tools to assist with choosing probiotic supplements:

This article was originally published on RACGP and has been adapted for dietitians

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