What are the benefits of peppermint?
You already know about peppermint as a flavoring for candy and cookies. The oils from the peppermint (Mentha piperita ) have an unmistakable icy-cool flavor and smell.
But peppermint oil seems to do more than freshen breath. It's a time honored remedy for sore throats. And in Germany, it's approved it as an aid to improve digestion and reduce bloating. Human studies have shown peppermint oil (in capsules) is helpful for treating irritable bowel syndrome (IBS), a condition of the intestines producing abdominal pain, constipation or diarrhea. A 2008 study published in the British Medical Journal found that peppermint oil was significantly better than a placebo for relieving the symptoms of IBS. In fact, it also seemed to out-perform both fiber and muscle relaxants, two more mainstream IBS treatments. In other human studies, peppermint oil applied to the forehead and temples helped relieve tension headaches.
How does peppermint work?
The active ingredient in peppermint oil is menthol. After a big meal, gas building up in your stomach can cause cramping, but menthol relaxes the valve between the stomach and the esophagus, allowing trapped gas to escape upward as a welcome, pressure-relieving burp. Menthol is a mild anesthetic that can block pain and nausea signals by numbing nerves in the gut, including those that would normally prompt nearby muscles to contract. One result: fewer muscle spasms that cause some of the symptoms of IBS.
Menthol lozenges can help calm coughs and soothe raw throats by numbing and relaxing throat muscles. Peppermint is a common ingredient in "natural" mouthwashes because it's an anti-bacterial agent that kills the germs that cause tooth decay and bad breath. Rubbing a few drops of it into your temples may also help relax temple muscles, easing some headaches.
How safe is peppermint?
Cough drops and peppermint leaf tea are safe unless you are allergic to peppermint, but undiluted peppermint oil (also called essential oil) can be toxic and irritating to the skin even in small doses. You should never ingest it except in coated capsule form. And don't give peppermint tea or menthol cough drops to children under five years of age; they can cause a choking sensation. Watch out, too, if you're prone to heartburn. While menthol's relaxing of the valve at the entrance to the stomach can soothe cramps by releasing gas, it sometimes also allows stomach acids to splash up into the esophagus, causing that burning sensation in the chest.
What's the best way to take it?
Enteric-coated peppermint oil capsules are your best bet for indigestion or IBS. They can be expensive, so check with your doctor, naturopath or pharmacist before you try taking them regularly for irritable bowel syndrome. Peppermint tea doesn't contain nearly as much menthol (fresh leaves are more potent than packaged teas), but it may ease minor stomach complaints. Pour a cup of boiling water over two teaspoons of crushed leaves and steep for ten minutes. Look for the leaves in specialty produce markets (or grow your own). You can find peppermint oil and tinctures at most health food stores. Keep in mind, though, that the government doesn't regulate herbal remedies as strictly as it does drugs, so quality and potency can vary from product to product. There are no required tests for safety or effectiveness, for example. In rare cases supplements may be contaminated with undesirable substances.
Kligler B and S Chaudhary. Peppermint oil. 2007. 75(7): 1027-1030. http://www.aafp.org/afp/2007/0401/p1027.html
University of Maryland Medical Center. Peppermint. 2006. http://www.umm.edu/altmed/articles/peppermint-000269.htm
Ford AC et al. Effects of fiber, antispasmodics, and peppermint oil in the treatment of irritable bowel syndrome: systematic and meta-analysis. British Medical Journal. 2008. http://www.bmj.com/content/337/bmj.a2313.full.pdf+html