Peppermint

While herbalists have used various mint species for thousands of years, the familiar garden perennial peppermint is a relative newcomer. That's because peppermint is a hybrid of spearmint and water mint first cultivated in England around the beginning of the eighteenth century. The plant is now grown throughout Europe and North America, with the Northwest part of the U.S. being a major supplier for the world market. The bulk of the crop is steam-distilled into the pale yellow essential oil, which is widely used as a flavoring agent in foods, candies, chewing gum, and toothpastes. An estimated one percent of the essential oil is used medicinally, as is a small percentage of the leaf crop for teas and other herbal preparations.

Traditional uses

Over the past three centuries herbalists have begun to use peppermint in many of the same ways that herbalists in ancient Egypt and China used other types of mints. That is, as a digestive remedy to treat heartburn, diarrhea, flatulence, and intestinal cramps. Peppermint leaf tea has become a popular treatment for nausea and vomiting due to morning sickness. The tea has also become a traditional remedy to relieve the discomforts of menstruation, to alleviate respiratory infections, and to promote liver and gallbladder function.

 Modern uses

Peppermint is now widely recognized as an effective remedy to regulate digestion. It has a calming effect on the smooth muscle of the digestive tract and can promote the flow of bile from the gallbladder into the small intestine, thus aiding the digestion of fats. Peppermint may help to relieve symptoms of nasal congestion. The essential oil can be diffused into the air and inhaled for its mildly stimulating effect on the nervous system and overall circulation. Modern aromatherapists say that peppermint oil clears the mind, helps to increase alertness, and can improve the performance of stressful visual tasks. Herbal companies add peppermint compounds to topical creams that can help relieve the pain and itching of hemorrhoids, insect bites, athlete's foot, and other skin ailments. Peppermint is a component of rubs used to relieve minor aches in muscles, nerves, and joints. Some people use the oil as an insect repellent and toothache remedy. Peppermint preparations can also help to prevent or treat:

loss of appetite - irritable bowel syndrome

gum disease - tension headache

Recent findings

A 1995 double-blind, placebo-controlled study determined that essential oil of peppermint rubbed into the forehead may be an effective tension-headache treatment capable of relaxing muscles and relieving pain.

A number of recent studies have found that enteric-coated peppermint oil formulations can reduce the symptoms of irritable bowel syndrome, including abdominal pain and distension, stomach rumbling, and flatulence. A 1998 meta-analysis study identified five double-blind, randomized, controlled trials that collectively indicate that peppermint oil could be effective at relieving the symptoms of irritable bowel syndrome, although the researchers noted that further studies were needed.

A British study found that peppermint oil is a potentially useful therapy for preventing the nausea that often occurs after a surgical operation.

 Do scientists know how it works?

The main therapeutic components of the plant are various flavonoids and the essential oil. Approximately fifty percent of the essential oil is menthol, a medicinally active alcohol. Applied to the skin, menthol dilates blood vessels and thus has a cooling effect. (Menthol has a similar cooling effect when it is taken into the mouth with air.) Studies have found that menthol has anti-microbial and anti-inflammatory actions.

Types of products

Peppermint is available as a tea, the dried leaf, an essential oil, and an herbal oil. It is also sold in liquid extracts and softgels. Some products combine it with ginger. Peppermint is widely used:

1) as a flavoring agent in toothpastes, soaps, gums, and sweets

2) in formulas and combination products for stomach and nausea, gas, headache, and digestion

3) in colon tea and dieter's tea

 Safety

Peppermint tea is generally safe and nontoxic, although it may cause intestinal discomfort in people who have gallstones. Infants and small children should not be given high doses. The essential oil is much more potent and needs to be used with caution. It may irritate the skin if it is applied undiluted or in high doses. Avoid putting the essential oil over more than a small patch of skin at a time because of menthol's pronounced cooling effect. The essential oil could cause an asthma-like attack if applied to the nasal area of infants or small children. Essential oils are not generally taken internally except with the supervision of an experienced therapist. Capsules containing tiny amounts of peppermint oil are often enteric-coated to prevent a burning sensation or other types of digestive discomfort.

References

Göbel, H., et al., "Essential plant oils and headache mechanisms," Phytomedicine (1995), 2(2):93-102

Liu, J.H., et al., "Enteric-coated peppermint-oil capsules in the treatment of irritable bowel syndrome: a prospective, randomized trial," J Gastroenterol (1997), 32(6):765-68

Pittler, M.H., and E. Ernst, "Peppermint oil for irritable bowel syndrome: a critical review and metaanalysis," Am J Gastroenterol (1998), 93(7):1131-35

Tate, S., "Peppermint oil: a treatment for postoperative nausea," J Adv Nurs (1997), 26(3):543-49