Are all probiotics equally good for your gut microbiome?

by Jennifer Bowden / 10 October, 2018
RelatedArticlesModule - Probiotics gut microbiome

Photo/Getty Images

The gut microbiome has become a key health focus, but not all yoghurts and probiotic supplements are born equally.

QUESTIONDo all commercially available yogurts contain probiotics? Are all probiotics equally good for your gut microbiome or are some more beneficial than others?

ANSWERThe health benefits of ingesting bacteria have been known for centuries. Fermented milk, for instance, is an age-old remedy for an upset stomach.

Now, after several decades of over-eager disinfection and bacteria-avoidance, we’re seemingly rediscovering how gut bacteria boost health. But relating that to what we eat is an inexact science, and product labelling is often not much of a guide.

First up, probiotics are a subset of microorganisms, and yogurt starter cultures are not necessarily probiotics, says the Ministry for Primary Industries.  In fact, the starter cultures for yogurt are not commonly probiotics.

If a label claims a yogurt “contains probiotics”, that constitutes a nutrition content claim. The label should also state the specific strain of probiotic used and the average quantity of that strain in colony forming units (CFUs).

At this point, it’s worth explaining the bacteria naming convention. Otherwise, any discussion of the benefits or otherwise of probiotics is like saying, “Eating food is good for us”. Yes, but which food?

So, Lactobacillus rhamnosus GG, for instance, is from the genus lactobacillus and species rhamnosus and the strain is GG. Some yogurt labels list the genus and species of bacteria the product contains, but don’t say the exact strain, nor the CFUs per serving, which is important information.

Despite widespread use of probiotic supplements, drinks and probiotic-containing yogurt, there is no evidence to suggest that randomly taking a probiotic-containing product is going to provide health benefits.

In fact, recent findings from two studies investigating the effect of an 11-strain probiotic supplement on the human gut revealed that many people’s digestive tracts prevent standard probiotics from successfully colonising them and there was considerable individual variation in how they affect the gut microflora. They also found that taking probiotics to counterbalance antibiotics could delay the return of normal gut bacteria to their original state.

Many strains of probiotic have been studied but it has been difficult to show a universal, consistent, positive cause-and-effect relationship for any single strain. And even if a particular strain was linked to a positive health effect, we would need to ensure the yogurt or food we consumed had a big enough dose of that probiotic.

Certain strains of probiotics have been linked to specific health benefits, including reducing the severity and duration of antibiotic-associated diarrhoea, eczema associated with cow’s milk allergy, respiratory tract infections, infant colic, bacterial vaginosis and urinary tract infections.

A Canadian study compared the prevalence and dosage of probiotic strains in the country’s food supply with dosages used in clinical trials and found the tested dosages were up to 25 times higher than that found in a serving of most foods.

Considering the wide range of probiotic species, strains and dosages, and how they interact with our individual gut microbiome, it is difficult to work out the health effect any particular one will have on us.

The only permitted health claim in New Zealand is for live yogurt starter cultures containing 108 CFU/gram of Lactobacillus delbrueckii, subspecies bulgaricus and streptococcus thermophilus, which improves lactose digestion.

Otherwise, go ahead and enjoy the taste of your probiotic yogurt – it may or may not be benefiting your gut microflora and health.

This article was first published in the September 29, 2018 issue of the New Zealand Listener.


The pioneering Kiwi surgeon who heads a world-leading team
104715 2019-04-21 00:00:00Z Profiles

The pioneering Kiwi surgeon who heads a world-lead…

by Clare de Lore

Harvard-based New Zealander Simon Talbot leads a team of surgeons performing astonishing hand transplants and plays a part in operations that...

Read more
Norah Jones’s new beginning and return to New Zealand
104817 2019-04-21 00:00:00Z Music

Norah Jones’s new beginning and return to New Zeal…

by Russell Baillie

The jazz songstress is staying inspired by writing with others.

Read more
Bill Ralston: Only fundamentalist Christians should be hurt by Israel Folau
104814 2019-04-20 00:00:00Z Social issues

Bill Ralston: Only fundamentalist Christians shoul…

by Bill Ralston

Israel Folau’s social-media post might condemn the Wallabies to Rugby World Cup hell, but the rest of us should ignore him.

Read more
What happens next with the Mueller report?
104863 2019-04-20 00:00:00Z World

What happens next with the Mueller report?

by Noted

Did Trump “corrupt” with intent?

Read more
The Heart Dances: Lifting the lid on the culture clash behind ‘The Piano’ ballet
104740 2019-04-20 00:00:00Z Movies

The Heart Dances: Lifting the lid on the culture c…

by Russell Baillie

Documentary offers an intriguing look at the clash of artistic sensibilities behind adapting The Piano into a ballet.

Read more
How this remarkable native insect is being saved
104836 2019-04-20 00:00:00Z Planet

How this remarkable native insect is being saved

by Jenny Nicholls

Principles of bird conservation are helping to save another remarkable native you’ve never heard of.

Read more
Environment Ministry 'unashamedly proud' of bleak report's honesty
104868 2019-04-20 00:00:00Z Planet

Environment Ministry 'unashamedly proud' of bleak…

by RNZ

The Secretary for the Environment Vicky Robertson said she was proud of the report's honesty and it was an important stocktake for the country.

Read more
The new What We Do in the Shadows is more dad joke than demonic
104712 2019-04-19 00:00:00Z Television

The new What We Do in the Shadows is more dad joke…

by Diana Wichtel

Diana Wichtel reviews a new American TV series based on the hit Kiwi comedy.

Read more