Lured by the promise of better digestion and a stronger immune system, Britons today spend about £1billion a year on probiotic supplements – quite a rise from an annual £62million in 2000.
Yet a survey has found that despite nearly half of all adults taking probiotics – spending on average £130 a year – nearly 80 per cent notice no significant health benefits from taking them.
The report, commissioned by pharmaceutical company Nordic Pharma UK, also found that while many of us believe probiotics can be good, most people are uncertain exactly why they work – or how we should take them.
And more than half (51 per cent) are unaware there are different probiotic strains to treat different conditions.
Our digestive tracts contain trillions of microbes, including viruses, fungi and bacteria – known as the gut microbiome – that help break down food so our bodies can absorb its nutrients.
We know that gut bacteria also have a direct effect on our immune system and even influence mental wellbeing.
One type of bacteria, Akkermansia muciniphila, is being investigated for its effect on blood sugar levels, for instance.
Experts are also turning their attention to microbiomes living in other parts of the body such as the mouth, skin and genital tract.
There’s no evidence to support the use of a daily probiotic for your general gut health, so it’s best to stick to a varied, plant-rich diet, according to Dr Megan Rossi
However, the gut microbiome is fragile and poor diet, long-term stress or taking antibiotics can all upset its delicate balance: the ‘bad’ bugs can overpower the good, with a knock-on effect on our health.
A varied diet with lots of fruit and vegetable fibre remains the best way to maintain this balance naturally (essentially the bacteria feed off this fibre).
But many of us are now taking a probiotic supplement as a sort of microbiome insurance policy. Yet with so many to choose from, how do you know which one to buy?
‘The problem is there’s a huge gap between the latest science on which probiotic strains actually work and the products you see on the shelves, which may not deliver what they promise,’ says Dr Megan Rossi, a dietitian and microbiome scientist at King’s College London.
To cut through the confusion, we asked experts for their advice on what to look for – and how to avoid wasting your money.
Do I need a probiotic for general gut health?
‘While the idea of a “one-size-fits-all” supplement for gut health sounds appealing, the latest scientific research shows that if you’re healthy, there’s no evidence to support the use of a daily probiotic for your general gut health,’ says Megan Rossi.
‘You’re better off sticking to a varied, plant-rich diet.
‘The science has moved on and in much the same way that a generic multivitamin hasn’t been shown to boost overall health, probiotics need to be much more targeted to specific conditions to be effective. There just isn’t good evidence that taking a general probiotic will help improve your digestion in any significant way.’
Probiotics are fragile and sensitive to damage in the manufacturing process, says Aidan Goggins, so powders or capsules tend to be a better bet than gummies and pressed tablets
Which probiotics are actually worth taking?
The Nordic Pharma UK survey found that half of people who take a probiotic believe it has been clinically proven to work.
‘But the truth is the vast majority of products available today are not backed by clinical trials,’ points out Megan Rossi.
‘Although some individual bacteria strains may have good science to support their claims, many products throw too many other strains into the mix.
‘These, crucially, have never been studied together and could compete against each other and throw the whole gut microbiome out of balance.’
The vast majority of studies – including a review of over 30 studies by the University of Washington in the US in 2021 – have shown no difference in effectiveness between multi-strain and single-strain products.
‘I personally don’t discriminate between multi-strain and single-strain products – as long as they are researched well, with good lab studies and published results to show the strains work well together,’ says Professor Glenn Gibson, a leading researcher on probiotics at the University of Reading.
What if I’m having to take antibiotics?
Antibiotics can disrupt your gut microbiome by killing off many of the beneficial bacteria.
This can allow harmful bacteria to thrive, which irritate the lining of the gut and cause diarrhoea for about a third of those on them.
‘I usually recommend taking a probiotic when on antibiotics and to take it between doses,’ says Simon Gaisford, a professor of pharmaceutics at University College London who researches probiotics. ‘That way the antibiotic shouldn’t kill the probiotic.’
The World Gastroenterology Organisation’s guidelines recommend a supplement containing the well-studied Lactobacillus rhamnosus while on antibiotics.
What other probiotic strains work then?
‘Each bacterial strain serves a unique function, requiring the correct delivery format and dose to truly make an impact,’ says Aidan Goggins, a pharmacist and independent adviser to the supplements industry.
There are ‘tens of thousands’ of bacterial strains that do different things in the body, adds Megan Rossi. ‘You wouldn’t take an iron supplement to treat a vitamin D deficiency, so why would you take a supplement that doesn’t address your specific need?
‘I’ve seen lots of products that don’t use the right strain for the condition they’re trying to address, so you’re just wasting your money. It’s important to know which strains have good evidence to back them up.’
For antibiotic-related gut issues or to prevent traveller’s tummy, Professor Gibson says he looks for products containing Lactobacilli and Bifidobacteria, ‘which are the most well-researched strains and have the best safety and efficacy records’. Other strains proven to work are:
For colds and flu: Lactobacillus rhamnosus and Bifidobacterium lactis. A 2022 review by the Cochrane group found that together these strains could reduce upper respiratory tract infections by one quarter.
For thrush and bacterial vaginosis: Lactobacillus bacterial strains La-14 and HN001 together. Research, including a 2018 study by University of Trieste in Italy, found that used together in an oral supplement, these strains can reduce symptoms of thrush and bacterial vaginosis.
For COLIC IN BABIES: Bifidobacterium lactis BB-12. A 2021 study by Chengdu Women’s and Children’s Central Hospital in China showed this strain significantly reduced the duration and number of episodes of crying and fussing in infants with colic and helped them sleep for longer.
Is it the more bacteria there are, the better?
The huge range in billions of bacteria between different probiotic supplements can be baffling – from 100 million to more than a trillion CFUs (colony-forming units of bacteria).
But more isn’t necessarily better, as effectiveness depends on the dose that’s shown demonstrable results in human trials.
‘I don’t get too hung up on numbers,’ says Professor Gibson. ‘It doesn’t actually take that many bacteria to have an effect.
‘In the same way that only a few cells of pathogens [illness-causing bacteria] can make us very ill, probiotics can still have positive influences at doses far below those present in many so-called “high dose” products.’
Are tablets, gummies or powders best?
‘Probiotics are fragile and sensitive to damage in the manufacturing process, especially heat and pressure,’ says Aidan Goggins.
‘So powders or capsules tend to be a better bet than heavily processed products such as gummies and pressed tablets – which may have exposed their bacteria to damaging conditions, meaning they could contain fewer bacteria than stated on the packaging.’ Professor Gaisford says liquid probiotics are best as ‘bacteria are living organisms which live in water’.
‘Powders or capsules contain desiccated bacteria [dried out bacteria] – great for shelf life of the product – but mean the bacteria must rehydrate [in the body] to recover viability [bring them back to life].
‘This takes time, which means the total percentage of live bacteria reaching the gut will always be lower than with a liquid where the bacteria are already live.’
For powders and capsules he recommends, ‘letting the contents dissolve in a little water so the bacteria recover for at least an hour before swallowing’.
How should I store my probiotics?
If there are no storage instructions on the label of capsules or powders, your probiotic (which contains dried bacteria) doesn’t need refrigerating – unlike liquid probiotics and yoghurt drinks, as these contain activated bacteria.
How long should I take them for?
This varies depending on why you’re taking them. ‘For example, we know that a probiotic designed to prevent respiratory illnesses is best taken daily over the winter months when rates of these infections are at the highest,’ says Megan Rossi.
‘A probiotic taken to avoid antibiotic-related stomach upset is most effective if started on the first day of the antibiotics course and then daily for at least a week after.’
When should I take them in the day?
Take them at least half an hour before meals – when your stomach acid is at its lowest and therefore less likely to damage the bacteria, says Aidan Goggins. ‘They’re also not then hindered by the food in your stomach.’
Avoid taking them with hot drinks, acidic fruit juices or alcohol, he adds. ‘These can degrade them and reduce their effectiveness. Taking them a couple of hours after antibiotics is also a good idea so they aren’t destroyed.’
- Dr Megan Rossi’s new range of probiotics is available at smartstrains.com, and from tomorrow at Tesco pharmacies, in store only.
