The results of a new Cedars-Sinai study suggest that an overgrowth of bacteria in the gut has been 'definitively linked' to Irritable Bowel Syndrome (IBS).
The study, published in the current issue of Digestive Diseases and Sciences, examined samples of patients' small bowel cultures to confirm the presence of small intestinal bacterial overgrowth - or SIBO - in more than 320 subjects.
This is the first study to use this "gold standard" method of connecting bacteria to the cause of the disease, one of the most common digestive conditions in the UK. It's thought that 10%-20% of people experience IBS at some point, and is twice as common in women as in men.
In addition, the manufacturer of probiotic drink Symprove today claimed a daily £2 dose could provide relief for IBS sufferers. Health drink manufacturers claim probiotic bacteria play an important role in digestive health and the immune system - although this has yet to be proved.
A study involving 186 people, aged 18 to 65, who had been diagnosed with moderate to severe IBS, found that two-thirds of patients given the drink reported a reduction in the severity of their symptoms at the end of a 12-week trial.
According the Daily Mail, more than one in five receiving the probiotic drink saw their symptoms fall from the severe category to mild.
Previous studies that have explored the role bacteria plays in the disease, have used breath tests to detect methane - a byproduct of bacterial fermentation in the gut. However, this study was the first to make the link using bacterial cultures.
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In patients with IBS, more than a third also were diagnosed with small intestine bacterial overgrowth, compared to fewer than 10% of those without the disorder. Of those with diarrhoea-predominant IBS, 60% also had bacterial overgrowth.
"While we found compelling evidence in the past that bacterial overgrowth is a contributing cause of IBS, making this link through bacterial cultures is the gold standard of diagnosis," said Mark Pimentel, director of the Cedars-Sinai GI Motility Program and an author of the study, in a statement.
"This clear evidence of the role bacteria play in the disease underscores our clinical trial findings, which show that antibiotics are a successful treatment for IBS."
Patients with IBS suffer symptoms that can include painful bloating, constipation and diarrhoea.