University of Adelaide researchers have shown for the first time how peppermint helps to relieve Irritable Bowel Syndrome, which affects up to 20% of the population.
In a paper published this week in the international journal Pain, researchers from the University's Nerve-Gut Research Laboratory explain how peppermint activates an "anti-pain" channel in the colon, soothing inflammatory pain in the gastrointestinal tract.
Dr Stuart Brierley says while peppermint has been commonly prescribed by naturopaths for many years, there has been no clinical evidence until now to demonstrate why it is so effective in relieving pain.
"Our research shows that peppermint acts through a specific anti-pain channel called TRPM8 to reduce pain sensing fibres, particularly those activated by mustard and chilli. This is potentially the first step in determining a new type of mainstream clinical treatment for Irritable Bowel Syndrome (IBS)," he says.
IBS is a gastrointestinal disorder, causing abdominal pain, bloating, diarrhoea and/or constipation. It affects about 20% of Australians and costs millions of dollars each year in lost productivity, work absenteeism and health care.
"This is a debilitating condition and affects many people on a daily basis, particularly women who are twice as likely to experience Irritable Bowel Syndrome," Dr Brierley says.
"Some people find their symptoms appear after consuming fatty and spicy foods, coffee and alcohol, but it is more complex than that. There appears to be a definite link between IBS and a former bout of gastroenteritis, which leaves nerve pain fibres in a heightened state, altering mechanisms in the gut wall and resulting in ongoing pain."
Dr Brierley says the recent floods in Queensland and Victoria could result in a spike of gastroenteritis cases in Australia due to the contamination of some water supplies in affected regions.
He said case studies in Europe and Canada showed that many people who contracted gastroenteritis from contaminated water supplies went on to experience IBS symptoms that persisted for at least eight years.
There is no cure for IBS and it often comes and goes over a person's lifetime.
Apart from gastroenteritis and food intolerance, IBS can be brought on by food poisoning, stress, a reaction to antibiotics, and in some cases is genetic.