Benefits Placebo | MeSH D019341 | |
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Aromatherapy uses plant materials and aromatic plant oils, including essential oils, and other aroma compounds for improving psychological or physical well-being.
Contents
It can be offered as a complementary therapy or, more controversially, as a form of alternative medicine. Complementary therapy can be offered alongside standard treatment, with alternative medicine offered instead of conventional, evidence-based treatments.
Aromatherapists, who specialize in the practice of aromatherapy, utilize blends of therapeutic essential oils that can be issued through topical application, massage, inhalation or water immersion to stimulate a desired response.
There is no good medical evidence that aromatherapy can either prevent or cure any disease, but it might help improve general well-being.
History
The use of essential oils for therapeutic, spiritual, hygienic and ritualistic purposes goes back to a number of ancient civilizations including the Chinese, Indians, Egyptians, Greeks, and Romans who used them in cosmetics, perfumes and drugs.
Oils are described by Dioscorides, along with beliefs of the time regarding their healing properties, in his De Materia Medica, written in the first century. Distilled essential oils have been employed as medicines since the invention of distillation in the eleventh century, when Avicenna isolated essential oils using steam distillation.
The concept of aromatherapy was first mooted by a small number of European scientists and doctors, in about 1907. In 1937, the word first appeared in print in a French book on the subject: Aromathérapie: Les Huiles Essentielles, Hormones Végétales by René-Maurice Gattefossé, a chemist. An English version was published in 1993. In 1910, Gattefossé burned a hand very badly and later claimed he treated it effectively with lavender oil.
A French surgeon, Jean Valnet, pioneered the medicinal uses of essential oils, which he used as antiseptics in the treatment of wounded soldiers during World War II.
Modes of application
The modes of application of aromatherapy include:
Materials
Some of the materials employed include:
Theory
Aromatherapy is the treatment or prevention of disease by use of essential oils. Other stated uses include pain and anxiety reduction, enhancement of energy and short-term memory, relaxation, hair loss prevention, and reduction of eczema-induced itching.
Two basic mechanisms are offered to explain the purported effects. One is the influence of aroma on the brain, especially the limbic system through the olfactory system. The other is the direct pharmacological effects of the essential oils.
In the English-speaking world, practitioners tend to emphasize the use of oils in massage. Aromatherapy tends to be regarded as a pseudoscientific fraud at worst.
Choice and purchase
Oils with standardized content of components (marked FCC, for Food Chemicals Codex) are required to contain a specified amount of certain aroma chemicals that normally occur in the oil. There is no law that the chemicals cannot be added in synthetic form to meet the criteria established by the FCC for that oil. For instance, lemongrass essential oil must contain 75% aldehyde to meet the FCC profile for that oil, but that aldehyde can come from a chemical refinery instead of from lemongrass. To say that FCC oils are "food grade" makes them seem natural when they are not necessarily so.
Undiluted essential oils suitable for aromatherapy are termed 'therapeutic grade', but there are no established and agreed standards for this category.
Analysis using gas liquid chromatography (GLC) and mass spectrometry (MS) establishes the quality of essential oils. These techniques are able to measure the levels of components to a few parts per billion. This does not make it possible to determine whether each component is natural or whether a poor oil has been 'improved' by the addition of synthetic aromachemicals, but the latter is often signaled by the minor impurities present. For example, linalool made in plants will be accompanied by a small amount of hydro-linalool, whilst synthetic linalool has traces of dihydro-linalool.
Effectiveness
There is some evidence that aromatherapy can help improve general well-being, but no good medical evidence that it can prevent or cure disease.
In 2015 the Australian Government's Department of Health published the results of a review of alternative therapies that sought to determine if any were suitable for being covered by health insurance; Aromatherapy was one of 17 therapies evaluated for which no clear evidence of effectiveness was found. Evidence for the efficacy of aromatherapy in treating medical conditions is poor, with a particular lack of studies employing rigorous methodology.
Safety concerns
Aromatherapy carries a risk of a number of adverse effects and this consideration, combined with the lack of evidence of its therapeutic benefit, makes the practice of questionable worth.
Because essential oils are highly concentrated they can irritate the skin when used in undiluted form. Therefore, they are normally diluted with a carrier oil for topical application, such as jojoba oil, olive oil, or coconut oil. Phototoxic reactions may occur with citrus peel oils such as lemon or lime. Also, many essential oils have chemical components that are sensitisers (meaning that they will, after a number of uses, cause reactions on the skin, and more so in the rest of the body). Some of the chemical allergies could even be caused by pesticides, if the original plants are cultivated. Some oils can be toxic to some domestic animals, with cats being particularly prone.
A child hormone specialist at the University of Cambridge claimed "... these oils can mimic estrogens" and "people should be a little bit careful about using these products." The Aromatherapy Trade Council of the UK has issued a rebuttal. The Australian Tea Tree Association, a group that promotes the interests of Australian tea tree oil producers, exporters and manufacturers issued a letter that questioned the study and called on the New England Journal of Medicine for a retraction. The New England Journal of Medicine has so far not replied and has not retracted the study.
As with any bioactive substance, an essential oil that may be safe for the general public could still pose hazards for pregnant and lactating women.
While some advocate the ingestion of essential oils for therapeutic purposes, licensed aromatherapy professionals do not recommend self-prescription due to the highly toxic nature of some essential oils. Some very common oils like eucalyptus are extremely toxic when taken internally. Doses as low as one teaspoon have been reported to cause clinically significant symptoms and severe poisoning can occur after ingestion of 4 to 5 ml. A few reported cases of toxic reactions like liver damage and seizures have occurred after ingestion of sage, hyssop, thuja, and cedar. Accidental ingestion may happen when oils are not kept out of reach of children.
Oils both ingested and applied to the skin can potentially have negative interactions with conventional medicine. For example, the topical use of methyl salicylate-heavy oils like sweet birch and wintergreen may cause bleeding in users taking the anticoagulant warfarin.
Adulterated oils may also pose problems depending on the type of substance used.