Peppermint (Mentha piperita): Health Benefits and Precautions

Peppermint (Mentha piperita) is a sterile, hybrid plant, created from the blending of watermint (Mentha aquatica) and spearmint (Mentha spicata). Peppermint is used for adding flavor or fragrance to several foods, cosmetics, soaps, toothpastes, mouthwashes, and other products - it is also popular for medicinal purposes.

Peppermint leaves can be used dried or fresh in teas.

Indigenous to Europe, peppermint today is cultivated all over the world.

Peppermint is popular as a traditional or folk remedy for several conditions and illnesses because of its calming effects, including flatulence, menstrual pains, diarrhea, nausea, depression-related anxiety, muscle and nerve pain, the common cold, indigestion, and irritable bowel syndrome.

This MNT Knowledge Center feature is part of a collection of articles on the health benefits of popular foods.

Peppermint oil

Peppermint oil is a concentrated oil made from the peppermint plant. Peppermint oil can be bought or made at home. The oil is extracted by steam distillation from the whole fresh or partly dried plant before it starts to flower.

According to an article in the scientific journal Natural Product Communications, the chemical components of peppermint oil are menthol (40.7%), menthone (23.4%), as well as menthyl acetate, 1,8-cineole, limonene, beta-pinene and beta-caryophyllene.

Peppermint for irritable bowel syndrome

A growing number of scientific studies have demonstrated that peppermint, in various forms, can help treat the symptoms of irritable bowel syndrome (IBS), including:

·         pain

·         bloating

·         diarrhea

·         gas.

The peppermint plant is a watermint and spearmint hybrid

A study carried out by researchers at McMaster University, Ontario, Canada, and published in the BMJ (British Medical Journal) concluded that doctors should recommend peppermint oil, fiber, and antispasmodics as first-line treatments for irritable bowel syndrome.

After looking at four trials involving 392 participants, lead researcher, Dr. Alex Ford and team found that peppermint oil was the most effective treatment when compared to antispasmodics and fiber.

A study published in the Mymensingh Medical Journal concluded that peppermint oil is effective in treating the symptoms of pain in diarrhea predominant IBS.

A study in the Belgian journal Revue Médicale de Bruxelles (article in French) acknowledged that "peppermint oil has an established visceral analgesic effect".

Dr. Stuart Brierley and team from the University of Adelaide's Nerve-Gut Research Laboratory in Australia discovered how peppermint activates an anti-pain channel in the colon, resulting in less inflammatory pain in the gut.

Dr Stuart Brierley said:

"Our research shows that peppermint acts through a specific anti-pain channel called TRPM8 to reduce pain sensing fibres, particularly those activated by mustard and chilli. This is potentially the first step in determining a new type of mainstream clinical treatment for Irritable Bowel Syndrome (IBS)."

Peppermint for skin conditions

Peppermint oil is widely used for calming skin irritation and itchiness, as well as reducing redness.

Although a large number of people swear by peppermint oil for soothing their skin, there is a lack of scientific evidence to support or challenge this belief.

Peppermint for headaches and migraines

Alexander P. Roussos MS and Alan R. Hirsch MD, from the Smell and Taste Treatment and Research Foundation, Chicago, reported in the journal Headache that for people with alliaceous migraines "Nose plug and counter stimulation with peppermint prevented the onset of headaches and associated symptoms." Alliaceous migraines are those caused by onions, garlic and other alliums (usually the odor).

Applying peppermint oil onto the forehead has been found to be effective in the treatment of tension headache. An article in American Family Physician quotes two trials that demonstrated the efficacy of peppermint oil for relieving the symptoms of tension headache. In fact, one of them found peppermint oil to be as effective as acetaminophen (Tylenol, paracetamol).

Peppermint for treating colds and flu

Menthol, the main chemical component of peppermint, is a very effective decongestant. Decongestants shrink the swollen membranes in the nose, making it easier to breathe.

Menthol is also an expectorant. Expectorants loosen and bring up mucus from the lungs. Expectorants help people with coughs.

In an Abstract in the journal Phytomedicine, scientists concluded "Based on its wide antimicrobial properties Olbas can be a useful agent for the treatment of uncomplicated infections of skin and respiratory tract". Olbas are complex essential oil distillates containing peppermint oil, eucalyptus oil, and cajuput oil.

Peppermint for treating nausea and vomiting during pregnancy

Although many pregnant women with "morning sickness" say they have experienced benefits from using peppermint in various forms, studies have either been inconclusive or contradictory.

Researchers from the Fatemeh Zahra Fertility and Infertility Health Research Center, Iran, reported in the journal Iran Red Crescent Medical Journal that according to their study, peppermint essential oil does not have any beneficial effects on the symptoms of nausea and vomiting during pregnancy.

If you are pregnant and are taking or plan to take peppermint in any form, talk to you doctor. Studies are inconclusive regarding the benefits or harms in using peppermint during pregnancy.

Peppermint for chemotherapy-induced vomiting

Cancer patients on chemotherapy commonly experience nausea and vomiting. Some studies have found that peppermint helps alleviate symptoms.

A study published in Ecancermedicalscience concluded that peppermint oil is "safe and effective for antiemetic treatment in patients, as well as being cost effective".

Peppermint oil for treating and healing chronic wounds

Research published in the journal ACS Nano has suggested that scientists have found a way to package antimicrobial compounds from peppermint and cinnamon in tiny capsules that can both kill biofilms and actively promote healing.

The researchers packaged peppermint oil and cinnamaldehyde, the compound in cinnamon responsible for its flavor and aroma, into silica nanoparticles. The microcapsule treatment was effective against four different types of bacteria, including one antibiotic-resistant strain. It also promoted the growth of fibroblasts, a cell type that is important in wound healing.

Precautions for peppermint use

Peppermint, like many other herbs, can interact with other herbs, supplements or drugs. Peppermint can also trigger side effects in some susceptible individuals.

If you are on any kind of medication, it is important to talk to your doctor about using peppermint.

Experts often recommend that you should not take peppermint if you:

·         are diabetic - according to some studies, peppermint may increase the risk of hypoglycemia (low blood sugar).

·         are less than 7 years old.

·         are taking antacids - some peppermint supplements are in capsule form. Their coating may break down too rapidly if the patient is also taking an antacid, increasing the risk of heartburn.

·         are taking cyclosporine, a medication taken by transplant recipients to prevent organ rejection.

·         have a hiatal Hernia.

·         have GERD (gastroesophageal reflux disease).

·         taking medications that are metabolized by the liver (ask your doctor).

·         are taking drugs for hypertension (high blood pressure).

Peppermint in various forms is also used for treating a number of other conditions, including dental plaque, shingles, urinary tract infection, and inflammation of the mouth. However, there is no scientific evidence to confirm its efficacy or safety.

According to the University of Maryland Medical Center, USA, test tube studies have found that peppermint kills some types of viruses, fungi and bacteria.