Peppermint

Mentha piperita

Because it is such a popular flavoring agent and so widely used in just about every kind of product intended for human consumption, you would think peppermint was one of our oldest herbs. But it is not. The plant is a natural hybrid or cross that sprouted in a field of spearmint growing in England in 1696. Ever since that time, peppermint, Mentha x piperita L.. of the family Lamiaceae, has been intensively cultivated for its fragrant volatile oil. Since it does not breed true from seed, peppermint is vegetatively propagated; there are numerous cultivated varieties.

Peppermint is used primarily for its stimulating, stomachic, and carminative properties in treating indigestion, flatulence (gas), and colic. Peppermint is usually taken in a moderately warm tea prepared from the leaves, several cups being slowly sipped to bring fairly prompt relief. In Europe, peppermint is incorporated in many tea mixtures intended to alleviate various ailments of the stomach, intestines, and liver. Although it may well contribute to certain actions of these mixtures, peppermint is often used simply as a pleasant flavor.

As an aid to digestion, its activity is due primarily to its contained volatile oil, which exists in the herb (leaves and flowering tops) in concentrations ranging from 1 to 3 percent. American peppermint oil contains from 50 to 78 percent of free menthol and another 5 to 20 percent of various combined forms (esters) of menthol. These major components are also largely responsible for peppermint's ability to stimulate the bile flow and promote digestion along with certain other flavonoid pigments with similar properties.

In addition, the volatile oil acts as a spasmolytic, reducing the tonus of the lower esophageal (cardial) sphincter and facilitating eructation (belching). This antispasmodic property may also account for the popularity of peppermint tea as a household remedy for menstrual cramps. Peppermint oil temporarily inhibits hunger pangs in the stomach, but soon the stomach resumes its peristaltic movements, which then become stronger than before. In this way it works to stimulate the appetite.

Peppermint, a hybrid of spearmint and wild mint, is a popular flavoring as well as a traditional medicinal herb. Oddly, there was no peppermint until late in the seventeenth century. Ever since then it has been cultivated. Both the leaf and the oil, obtained by steam distillation, are utilized.

Peppermint leaves contain between 1 and 3 percent of essential oil. Around half of the oil is composed of menthol (35 to 55 percent in European oil; 50 to 78 percent in American oils), with related compounds making up some of the remainder. Menthone comprises 10 to 35 percent of the oil. There are more than one hundred other constituents, including a variety of monoterpenes and sesquiterpenes. The exact proportions of the different ingredients differ from one variety to another and with plants grown in different locations. The leaves also contain flavonoids such as luteolin, rutin, hesperidin, and others.

The most common use of peppermint is for digestive problems. The dried leaves are often made into a tea sipped for indigestion, cramps, or gas. The essential oil has been shown to be effective at relieving spasms of smooth muscle through calcium-channel blocking activity. This could make peppermint oil useful in relieving spasms of the colon. Enteric-coated peppermint oil is used in the short-term treatment of irritable bowel syndrome, although not all double-blind stud- ies have shown statistically significant benefits. Gastroenterologists in England sprayed dilute peppermint oil directly on the instrument used for colonoscopy to prevent spasm. This innovative use of peppermint oil has not been widely adopted.

Peppermint oil and leaf flavonoids both increase the production of bile. This lends credence to the herb's traditional use as an aid to digestion. In addition, menthol lowers the activity of a liver enzyme (HMG CoA reductase) and might in theory lower cholesterol. This possible therapeutic use is hypothetical and has not been clinically tested. Likewise, peppermint oil has antibacterial and antiviral properties in the test tube, but it is not used to treat infections. Peppermint tea is, however, sometimes used to alleviate the discomfort of gastroenteritis.

Menthol or peppermint oil is sometimes added to hot water so that the vapors can be inhaled for colds and congestion. In addition, menthol or peppermint may be included in cough lozenges. Menthol is a common ingredient in rubs intended to relieve sore muscles or joints and may be used topically to soothe itchy skin.

Peppermint is both cooling and warming. When taken internally peppermint induces heat and improves the circulation and by dispersing blood to the surface of the body it causes sweating. This can be put to good use for chills and fevers, colds and flu. Its astringent and decongestant action helps relieve stuffiness and catarrh.
Peppermint makes a good general tonic to recharge vital energy and dispel lethargy. The refreshing taste of mint is followed by a cooling and numbing effect which extends to the respiratory tract, also apparent on the skin. Peppermint has an analgesic effect and makes an excellent local application when the fresh leaf or lotions are applied to relieve the pain of inflamed joints in arthritis and gout, for headaches, neuralgia, sciatica and general aches and pains.

Internally, peppermint has a relaxing effect, calming anxiety and tension and relieving pain and spasm. Peppermint can be used for menstrual pain, asthma and insomnia. In the digestive tract it relaxes smooth muscle and reduces inflammation, relieving pain and spasm in stomach aches, colic, flatulence, heartburn, indigestion, hiccoughs, nausea, vomiting and travel sickness. The tannins help protect the gut lining from irritation and infection and make it useful for griping in diarrhea, spastic constipation, Crohn's disease and ulcerative colitis. The bitters stimulate and cleanse the liver and gallbladder, helping to prevent gallstones.
The volatile oils have an antiseptic action, and are now confirmed as antibacterial, antiparasitic, antifungal and antiviral, useful for treating skin problems such as cold sores and ringworm.

The menthol in the oil is responsible for an antiseptic effect on the body as a whole. The leaves, with their combination of constituents are useful in the treatment of digestive disorders, having an antispasmodic effect which is calming on the gut, especially where there is gastric upset due to over-indulgence. Peppermint is also used in complaints such as irritable bowel syndrome, gastritis, and where there is excess wind and colic. Peppermint has a diaphoretic element which encourages sweating, so has been used in colds and flu to cool down a fever. In Chinese terms peppermint is also used to disperse fever, headaches, and coughs, and is used in the early stages of colds and flu. Additionally, the Chinese use peppermint for rashes, for example in measles, as it encourages the rash to progress and thereby speeds recovery. Peppermint can also act as a painkiller, when applied externally. The oil has antibacterial properties.

Other names

• Balm Mint
• Brandy Mint
• Curled Mint
• Lamb Mint
• Lammint
• Phudina
• Wu-pa-ho

Parts used

Aerial parts.

Uses

Digestive problems - Peppermint is excellent for the digestive system, increasing the flow of digestive juices and bile and relaxing the muscles of the gut. Peppermint reduces colic, cramps, and gas, and helps to soothe an irritated bowel. In soothing the lining and muscles of the colon, it helps diarrhea and relieves a spastic colon (often the cause of constipation).
Pain relief - Applied to the skin, peppermint relieves pain and reduces sensitivity. Peppermint also relieves headaches and migraines linked to digestive weakness.
Infection - Diluted oil is used as an inhalant and chest rub for respiratory infections. The whole herb is important for digestive infections.
Peppermint is also used to treat tropical travel diseases.
Culinary uses - Float fresh mint leaves on cool summer drinks and fruit punches. Mint is as essential for mint julep as bourbon, and is a natural addition to any gin-based drink.
Enliven salads and hot and cold soups with fresh mint.
Bring out the flavor of peas, new potatoes, and baby carrots by adding sprigs of fresh mint to the cooking water.
Use fresh or dried mint to season savory dips, butter, sauces, and jellies, especially the classic mint sauce or mint jelly served with roast lamb.
Season fish, poultry, and meats with mint, and use it to add zest to bean and lentil-based dishes.
Unless you're using mint as a garnish, always crush the leaves before use to obtain optimum flavor.
Add sprigs of fresh mint to vinegar.
Brew a soothing cup of mint tea by infusing 5 ml (1 teaspoon) of dried leaves or 15 ml (3 teaspoons) of crushed fresh leaves in 250 ml (1 cup) of boiling water. Steep to taste.
Mints are used commercially to flavor confectionery, chewing gum, soft drinks, baked goods, ice cream, gelatins, syrups, and liqueurs.
Craft uses - Add aromatic mint leaves to sachets and potpourris.

Habitat & cultivation

Peppermint grown commercially and in gardens throughout Europe, Asia, and North America.
Mints grow best in moist, deep, loosely textured sandy soil that is rich in humus. Recommended pH range for peppermint is 6.0 to 7.5.
Many mints, including peppermint and spearmint, thrive in full sun, but also do very well in partial shade. Some mints, like water mint, tolerate considerable shade. Corsican mint must have shade. In northern areas, mints won't develop their best flavor and fragrance if not grown in full sun. Keep well watered.
May be grown from seed, but this is not advisable, as most mints do not come true from seed.
Propagate mints from cuttings taken from established plants before they bloom, or by dividing existing plants, optimally in the early spring, or buy from nurseries or garden catalogs. Space plants 45 cm (18 inches) apart.
Once established, mints spread very quickly by underground runners or stolons. To prevent mints from taking over your herb garden, plan on digging up unwanted runners each spring, or curb the runners by sinking drainage tiles or plastic dividers in the soil around the plants, to a minimum depth of about 30 cm (12 inches). Or plant mints in large containers or pots with drainage holes, sunk in the ground.
Pinch off the flowers to promote bushy growth.
Renew mints every 3 years by dividing and replanting the roots in the spring or fall. Peppermint, in particular, does not grow well in the same location for more than a few years, and should be moved to a new spot.
Susceptible to infestations of aphids, cutworms, spider mites, and mint flea beetles, as well as verticillium wilt disease and rust, if the soil is too rich. Diseased plants should be dug up and burned promptly. Replant next season in a different location.
Where winters are usually harsh, cover the plants with straw (but not soil) to prevent damage to the runners.
Establish indoor plants in commercial potting soil in the spring or early fall. Containers or pots need to be large enough to give the creeping roots sufficient room to develop.
Indoor plants need at least 5 hours of strong sunlight daily. Keep the soil most but not soggy. Apply a liquid houseplant fertilizer at half strength every 3 or 4 weeks. To prevent the plants from flowering and ensure tastier leaves, keep the stems cut back to 13 cm (5 inches). If plants start to yellow, repot into a larger container, or divide the root mass into separate pots.

Research

Volatile oil - Research has shown that the volatile oil is strongly antibacterial. Menthol (a constituent of the oil) is antiseptic, antifungal, cooling, and anesthetic to the skin, although it is also an irritant.
Whole herb - The whole plant has an antispasmodic effect on the digestive system. Clinical trials in Denmark and Britain during the 1990s have confirmed its value in the treatment of irritable bowel syndrome.

Constituents

Peppermint contains essential oil, up to 1.5 per cent, containing menthol, flavonoids, rosmarinic acid.

How much to take

For internal use, a tea can be made by pouring 250 ml (1 cup) of boiling water over 1 teaspoon (heaped) of the dried leaves and steeping for five to ten minutes; three to four cups daily between meals can relieve stomach and gastrointestinal complaints. Peppermint leaf tablets, capsules, and liquid extracts are often taken at 3-6 grams per day. For treatment of irritable bowel syndrome (IBS), 1-2 capsules of the enteric-coated capsules containing 0.2 ml of peppermint oil taken two to three times per day may be preferable. For headaches, many people apply a combination of peppermint oil and eucalyptus oil diluted with base oil to the temples at the onset of the headache and every hour after that or until symptom relief is noted.

Side effects

Peppermint tea is generally considered safe for regular consumption. Peppermint oil, in large amounts, can cause burning and gastrointestinal upset in some people. It should be avoided by people with chronic heartburn. Some individuals using the enteric-coated peppermint capsules may experience burning sensation in the rectum. Rare allergic reactions have been reported with topical use of peppermint oil. Peppermint tea should be used with caution in infants and young children, as they may choke in reaction to the strong menthol; chamomile is usually a better choice for this group.
Do not give peppermint tea to babies and young children as the menthol may cause asphyxiation.

Collection & harvesting

Pick leaves and stem tips for fresh use at any time once the plants are about 15 cm (6 inches) tall. For best flavor, pick before the plants flower.
For drying, cut stems to just above the lowest set of leaves. Harvest before flowering, cutting stems in the morning, after the dew dries. Hang leafy stems upside down in small bunches in a shady location to dry. When dry, strip leaves and store in airtight jars in a dark location. Don't crumble leaves until you are ready to use, as their flavor will diminish.
Freeze leaves in butter, oil, or ice cubes for later use.

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