Peppermint tea is one of my favourite refreshers, so I was interested to read a paper(1) published in the latest issue of the British Medical Journal linking peppermint in the treatment of IBS (irritable bowel syndrome).  Back in August I wrote three lengthy pieces investigating IBS and this paper provides a nice update. 

The key to IBS is to try and find a cause to treat, this is very individual and may be linked to stress, emotions, food intolerances and more.  Any sort of diagnosis needs to be done in conjunction with a health professional.  However, it is always good to have some idea of the natural remedies that can help reduce symptoms.  The research in the British Medical Journal was a review of randomised controlled trials looking into the effect of fibre, antispasmodics (prescribed medication) and peppermint oil in the treatment of IBS.

Fibre
Traditionally, people with irritable bowel syndrome were instructed to increase their daily intake of dietary fibre, because of its potentially beneficial effects on bulking stools and moving them through the intestine more quickly (speeding up intestinal transit time).  However, many individuals with IBS found this advice unhelpful and some people reported that it made the condition worse.  The study looked at types of fibre and their usefulness in IBS treatment.  The investigators found that bran fibre (usually from wheat) had no effect on IBS symptoms.  However, ispaghula fibre, a soluble fibre derived from plaintain, did have a beneficial effect and reduced persistent symptoms of IBS.  The authors of the study indicate that ispaghula may be particularly beneficial to individuals who suffer constipation as one of their major IBS characteristics.

Ispaghula husk is readily available to buy from health-food stores and pharmacies as well as online. 

Antispasmodics
Antispasmodic medications attempt to reduce spasms in the digestive system.  Doctors frequently prescribe these types of medication for IBS symptoms, particularly when an individual is suffering from bloating and pain.  In the study 12 drugs were assessed.  Only 5 of these were shown to bring about a relief for IBS symptoms.  Some of the drugs, which are specifically licensed for use in IBS e.g. mebeverine, dicycloverine and alverine actually seemed to have very little evidence behind them.  The best evidence seemed to be for a drug called hyoscine.  The most common side effects for this type of medication are dry mouth, dizziness, and blurred vision, but none of the trials reported any serious adverse events.

It is not really known why antispasmodics are helpful for IBS sufferers.  The authors of this study note that “The biological rationale for the efficacy of antispasmodics is unclear.....antispasmodics may act by reducing colonic contraction and transit time and therefore pain and stool frequency”.  In light of the evidence discussed in this medical journal I would think that further studies are necessary to investigate the use of these drugs in patients with IBS to see if they really are helpful.

Peppermint oil
There were fewer available studies to analyse for the use of peppermint oil.  However, the studies that have taken place with this remedy show consistently positive results for use in IBS patients.  In fact peppermint oil appeared to be the most effective treatment for IBS when assessed via a measure called NNT, or number needed to treat, a measure of the number of individuals that need to be treated for one to get significant benefit.  Peppermint appears to have natural antispasmodic properties and is widely available over the counter in capsule form.  Larger trials of this traditional remedy would be welcome.

The authors conclude their paper by talking about the current guidelines for the management of IBS, they discuss the fact that these guidelines have been set around previous studies that have potential methodological flaws.  In the UK “Antispasmodics are recommended as first line treatment, particularly when pain and bloating are the predominant symptoms, although which of these drugs should be preferred is not stated”(1).  They also suggest that the current clinical guidelines be updated to take into account their findings.

(1) Ford AC et al.  2008.  Effect of fibre, antispasmodics, and peppermint oil in the treatment of irritable bowel syndrome: systematic review and meta-analysis. BMJ.  337:a2313

Written by Ani Kowal