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.

Latest

Win an Oscar Wilde prize pack, including books and double passes
100464 2018-12-14 10:08:08Z Win

Win an Oscar Wilde prize pack, including books and…

by The Listener

Enter and be in to win The Selfish Giant, The Picture of Dorian Gray, The Happy Prince and Other Stories, and a double pass to The Happy Prince.

Read more
Trends in 2018: What Kiwis searched for this year
100457 2018-12-14 09:38:50Z Life in NZ

Trends in 2018: What Kiwis searched for this year

by RNZ

Here's what piqued our interest this year.

Read more
The curious connection between these new celebrity biographies
100448 2018-12-14 09:13:59Z Books

The curious connection between these new celebrity…

by Russell Baillie

Our reviewer wades into a flood of celebrity biographies and memoirs and finds they’re all connected in some way.

Read more
Hop to it: The best Kiwi beers for summer
99461 2018-12-14 00:00:00Z Dining

Hop to it: The best Kiwi beers for summer

by Michael Donaldson

Here's what to crack open on a hot day, from our very own Kiwi brewers.

Read more
Te Atatu's new cafe The Sugar Grill celebrates local history and family
100443 2018-12-13 16:46:27Z Auckland Eats

Te Atatu's new cafe The Sugar Grill celebrates loc…

by Jean Teng

Nickson Clark's new cafe The Sugar Grill is a project 19 years in the making.

Read more
Time Magazine’s Person of the Year recognises the global assault on journalism
100431 2018-12-13 11:36:23Z World

Time Magazine’s Person of the Year recognises the …

by Peter Greste

Time Magazine has just announced its “Person of the Year” for 2018, and for once, it isn’t one person.

Read more
The devastating effect of discarded Christmas plastic
100417 2018-12-13 09:31:47Z Planet

The devastating effect of discarded Christmas plas…

by The Listener

Over the European holiday season, the Mediterranean Sea’s plastic load rockets by a whopping 40%, as people buy then simply ditch plastics like lilos.

Read more
The worst humanitarian crisis in the world that no one knows about
100384 2018-12-13 00:00:00Z World

The worst humanitarian crisis in the world that no…

by Todd Pitock

A country rarely in the media spotlight, here's why we can't ignore Chad.

Read more