Peppermint was not “officially” discovered until 1696, but we’ve probably been using it for thousands of years. After-dinner mints are used to reduce the gastrocolic reflex, the urge to defecate following a meal. The stretching of nerves in the stomach triggers spasms in the colon, which makes sense because it allows us to make room for more food coming down the pipe. Peppermint, like in our after-dinner mints, relaxes the colon’s muscles.
When researchers took circular strips of human colon removed during surgery and laid them out on a table, they spontaneously contracted on their own about three times per minute. Isn’t that kind of creepy? But when more and more menthol from peppermint was dripped on them, the contractions still occurred but were not as strong.
If peppermint can relax the colon and reduce spasms, might it be useful during a colonoscopy, as first suggested 30 years ago? Colonic spasms can hinder the progress of the scope and cause the patient discomfort. So, researchers sprayed peppermint oil on the tip of the scope, and, in every case, the spasm was relieved within 30 seconds. Thirty seconds, however, is a long time when you have a scope snaking inside your colon. The next innovation was to use a hand pump to flood the entire colon with a peppermint oil solution before the colonoscopy, which caused the spasming colon to open up within 20 seconds. This is a simple, safe, and convenient alternative to injecting an anti-spasm drug, which can have an array of side effects.
Researchers saw similar results during upper endoscopy, with peppermint working better, quicker, and safer than drugs. Another study also found positive results when peppermint was mixed into barium enemas. But wouldn’t it be easier just to swallow some peppermint oil instead of squirting it up the rectum? Researchers looked at this alternative in a study using premedication with peppermint oil before colonoscopy. Just popping a few peppermint oil capsules four hours before the procedure sped up the entire process. Both doctor and patient satisfaction increased because reducing colon spasms can reduce pain and discomfort, as well as make the scope easier to insert and withdraw.
Michael Greger, M.D.
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