Both the leaves and the oil, which is obtained by steam distillation of the leaves, are used and peppermint remains an incredibly versatile herb. Today, it is used to soothe the digestive tract, ease indigestion and irritable bowel syndrome (IBS), cramping pains and other stomach complaints. It also freshens the breath and may clear nasal blockages too.
Dr Sarah Brewer says: ‘Peppermint oil is a rich source of menthol, an essential oil with antiseptic and analgesic (pain-reducing) properties. It is one of the most effective herbal remedies for IBS and reduces abdominal pain and cramping, as well as relieving indigestion.’
What does peppermint oil do?
Peppermint oil contains 40 different compounds; the most important medicinal ingredient appears to be menthol, a natural analgesic or pain reliever.
The key action of peppermint oil appears to be its anti-spasmodic, muscle-relaxing benefits in the stomach and intestinal tract. Taking it internally appears to speed up the early phase of digestion. It also aids digestion by stimulating secretion of digestive juices and bile and reduces flatulence.
IBS stomach cramps
IBS is a collection of gut symptoms which include stomach cramps, diarrhoea, constipation and bloating. It’s estimated to affect around 10 to 20 per cent of the UK population.
Peppermint oil has an anti-spasmodic effect on the gut, relieving muscle cramps in the intestines. It is one of the most effective treatments for IBS; studies have shown it is a safe and effective, short-term treatment.
A meta-analysis of data from 12 trials, involving almost 600 people, explored the effectiveness of fibre, antispasmodics and peppermint oil in treating IBS. The number needed to treat (NNT) to prevent one person having persistent symptoms for peppermint oil was 2.5, making it the most effective therapy (compared to a NNT of 11 for fibre and five for antispasmodic drugs).
Almost everyone suffers with indigestion at some point and shop-bought antacids for heartburn and indigestion commonly include peppermint oil. Research has revealed peppermint oil is effective in reducing symptoms of dyspepsia (indigestion or upset stomach) that can include pain in the upper abdomen, bloating, nausea and burping.
Getting peppermint from your diet
You can use peppermint leaves in cooking or make them into a tea. Try steeping teaspoons of dried peppermint leaf in 250ml of hot water for five to 10 minutes, covering the cup to stop the volatile oil from escaping. Alternatively, get the herb’s digestive-enhancing effects from a supplement.
Peppermint oil is well tolerated and appears very safe unless used in excessively high doses when it can potentially become toxic. Possible side effects include allergic reactions and heartburn. As it relaxes gastrointestinal muscles, peppermint oil may aggravate the symptoms of a hiatus hernia (when part of the stomach protrudes up through an opening in the diaphragm, a large sheet of muscle between the chest and the abdomen).
There are no official guidelines, but a dose of one 100mg capsule after meals as required is recommended.