Probiotics (sold by the million as drinks, yoghurts or spreads) claim to have a range of benefits for health – by boosting ‘friendly bacteria’ in the gut. But new research shows there is little evidence probiotics have any effects for healthy adults.
There is a huge market for probiotics, estimated to soon be worth £29 billion globally. Many are marketed at the general population and they are massively popular in the UK.
A research team from the University of Copenhagen looked at the results of seven trials of probiotic products. Each trial studied the effect of probiotics on the faecal bacteria (microbiota) of healthy adults, as a measure of what was happening in the gut. In only one of the seven studies was there any change. This new review, published in the journal Genome Medicine, concluded there was little evidence they can help healthy adults.
Oluf Pedersen, professor at the University of Copenhagen and senior author of the research said:
While there is some evidence from previous reviews that probiotic interventions may benefit those with disease-associated imbalances of the gut microbiota, there is little evidence of an effect in healthy individuals.
There are caveats to this discovery. The studies that the University of Copenhagen analysed had small sample sizes, ranging between 21 and 81 people. Also, while the scientists found no real health benefits for healthy people, previous studies have shown that probiotics can be beneficial for people with irritable bowel syndrome, or diarrhoea.
The trillions of bacteria that live in the gut, part of the human microbiome, are of increasing interest to researchers. The gut bacteria have been dubbed the ‘forgotten organ’ by some. They can have a big impact on health – an unbalanced microbiome has been linked to a range of diseases from obesity, autoimmune disease, colon cancer and diabetes.
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