A new type of probiotic – designed specifically to be used alongside antibiotics – has hit supermarket and pharmacy shelves. But with often heftier price tags attached, are they worth forking out for the next time you get sick?
Antibiotics are the standard treatment for a range of bacterial infections, from pneumonia to whooping cough and meningitis.
More than 30 million prescriptions are issued each year in the UK – but they can also wreak havoc on your digestive system, with around a third of users experiencing diarrhoea.
This is because they are broad-spectrum medications, meaning they target a wide range of different bacteria at once; and as well as killing those responsible for infections, they also kill off many of the beneficial bacteria in your gut.
This disrupts the overall balance of your microbiome and can allow harmful bacteria to thrive, causing not only diarrhoea, but stomach cramps and other gut-related problems too.
People on long-term antibiotics – for example, for acne or recurrent urine infections – can find their microbiome is disrupted for years, which some experts believe can lead to serious complications beyond the gut. This can include metabolic problems, such as type 2 diabetes, or inflammatory conditions such as asthma.
As our understanding of the gut’s microbiome and its importance grows, GPs and gut health doctors increasingly advise taking probiotic supplements either during or after a course of antibiotics.
Probiotic supplements contain bacteria to replenish levels of ‘good’ organisms in your gut. But is this actually the most effective way to restore good gut health?
GPs and gut health doctors increasingly advise taking probiotic supplements either during or after a course of antibiotics
Antibiotics can disrupt the balance of your microbiome, which can cause diarrhoea, stomach cramps and other gut-related problems
A 2021 review of 36 studies, published in the Journal of Clinical Gastroenterology, found that taking the probiotic strain Lactobacillus rhamnosus – one of the most common bacteria strains found in many probiotic supplements – reduced the incidence and duration of loose stools and bloating.
Yet a 2018 study in the journal Cell found that taking probiotics after a course of antibiotics might actually delay your gut’s microbiome returning to its normal balance.
The researchers in the latter study gave both mice and humans a preparation containing 11 strains of the most widely used probiotics. These did indeed colonise the gut effectively – but also apparently delayed the microbiome’s return to its original balance.
In fact, those taking the probiotics took a full six months to return to their normal balance compared to the placebo group, whose microbiome bounced back just three weeks after stopping the antibiotics.
It’s thought this is because the probiotics introduced species of bacteria not normally present in the recipients’ microbiomes. These appeared to further crowd out the remaining original healthy bacteria (already depleted by antibiotic treatment), slowing the re-establishment of a ‘baseline’ gut ecosystem.
Simon Gaisford, a professor of pharmaceutics at University College London, says that while the results of taking probiotics with antibiotics have generally been mixed, the 2018 study involved only 21 people, ‘which means it’s not definitive in its own right’.
A study he was part of – as yet unpublished – tested the recovery of the gut microbiome in the lab after antibiotic treatment using a probiotic (containing Lactobacillus rhamnosus and three other strains) and showed ‘faster recovery – equivalent to just a few days in most people’, he says.
‘So I would say that there are mixed results so far and you probably get different results depending on just which probiotic you take,’ he adds. ‘Because taking oral antibiotics is usually quite detrimental to your gut bacteria, I’d still say taking a good probiotic supplement while on a course of antibiotics is sensible.’
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Simon Gaisford, a professor of pharmaceutics at University College London, says ‘taking a good probiotic supplement while on a course of antibiotics is sensible’
Glenn Gibson, a professor of food microbiology at the University of Reading, has long supported taking probiotics alongside antibiotics.
‘I’m not convinced by small studies that suggest probiotics may delay the gut microbiome returning to normal,’ he says.
‘It’s a long-standing observation that probiotics help reset the gut microbiome after antibiotic use. They help the good bacteria thrive and multiply.’
However, he recommends taking a well-researched strain (though these are contained in most products on the market).
So should we all take probiotics following antibiotics?
Professor Gaisford says that probiotics can be helpful, but timing is crucial. He warns against taking both pills at the same time ‘as the antibiotic will just kill the probiotic bacteria’. Instead, take your probiotic between antibiotic doses.
Probiotics also differ in terms of strain and formulation.
‘There are many probiotic species that have health claims made for them, but Lactobacillus rhamnosus – one of the most researched bacterial probiotic strains – is noted for its ability to survive stomach acid and stick to the intestinal lining,’ says Professor Gaisford. It’s been investigated for its role in microbial recovery after antibiotic use, as well as in supporting the gut barrier.
‘Lactobacillus rhamnosus – one of the most researched bacterial probiotic strains – is noted for its ability to survive stomach acid and stick to the intestinal lining,’ says Professor Gaisford
So convincing is the research that the World Gastroenterology Organisation’s guidelines now recommend taking a supplement with Lactobacillus rhamnosus while on antibiotics.
It’s not the only useful strain: it belongs to a group known as lactic acid bacteria, explains Professor Gaisford – named so because they produce lactic acid. ‘A more acidic gut environment appears to help support good bacteria and kill off the bad’, he says.
Nearly all probiotic species shown to be beneficial when taking antibiotics and for general gut health belong to this category – so you don’t necessarily need a probiotic product specifically stating it’s for use after antibiotics.
Another supplement will work, ‘as long as it contains Lactobacillus rhamnosus and other lactic acid bacteria – all of which start with the name “Lactobacillus”,’ says Professor Gaisford.
It can work out cheaper too. Omni Biotic 10 AAD, one of the top-selling post-antibiotic probiotics, costs about £43 for 30 days; while Optibac Every Day, which contains Lactobacillus rhamnosus, costs roughly £13.50 for 30 days, for example.
Another ingredient to look for is Saccharomyces boulardii, a yeast-based probiotic which a review in 2020 by the Medical University of Gdansk in Poland found helped prevent antibiotic-linked diarrhoea and restore a healthy gut microbiome.
