Health Studies 301 Complementary and Alternative Therapies

Study Guide: Unit 13

Aromatherapy

A candle being used to heat an aromatic oil. Hugo.arg, 2007, CC BY-SA 3.0.

Aromatherapy is the therapeutic use of essential oils, which are distilled from parts of plants, including flowers, leaves, seeds, wood, roots, and bark. Oils may be inhaled, diffused in the air, added to a bath, applied topically in lotions, and even ingested internally. Absorption through the skin and inhalation are considered safe, but consuming essential oils could result in poisoning.

Learning Objectives

Upon completion of Unit 13, you should be able to

• define aromatherapy and explain the nature of this therapy.
• determine the effectiveness of aromatherapy by analyzing the available research.
• identify trends and issues related to the use of aromatherapy.

Learning Activities

Study Questions

As you complete the activities for Unit 13, keep the following questions in mind. You may want to use the Personal Learning Space wiki on the course home page, and answer these questions as a way of keeping notes to focus your learning.

1. What are the main medicinal substances and methods of aromatherapy?
2. How are homeopathy and aromatherapy similar?
3. How is aromatherapy practice regulated?
4. What are the possible benefits of aromatherapy?
5. What are the possible risks and hazards associated with aromatherapy?

Unit 13 Discussion Forum

When you have completed the other activities for this unit, answer at least one of the questions in the Unit 13 Discussion Forum, and respond to at least one post by a fellow learner.

The more questions you answer, the better prepared you will be for the final exam!

Read

In addition to the notes provided here, read in the textbook:

Micozzi, M. (2019). Fundamentals of Complementary, Alternative, and Integrative Medicine. Pages 409–414.

The World of Aromatherapy

Aromatic plants, incense, oils, and perfumes have been used throughout history for masking unpleasant odours, embalming, or for religious ceremonies.

The organization of aromatherapists in Canada is similar to that for homeopaths, as described in the previous unit. In other words, there is no legal requirement for a practitioner of aromatherapy to be licensed by an agency of the government, but there is a professional organization for aromatherapists: the Canadian Federation of Aromatherapists (https://www.cfacanada.com). Much like other professional bodies, the organization provides information to the public and maintains a registry of members who have achieved the required level of training.

In Canada, aromatherapy is firmly in the camp of CAM therapies. However, in parts of Europe, aromatherapists often work in a conventional medical setting. (This is similar to the situation with homeopathy.)

As is often the case with several other CAM therapies, those who advocate aromatherapy sometimes make claims that are alien to conventional biomedical thinking. We see this in the section of the chapter headed “Vibrational Frequency of Plants” (pages 411–412).

Essential Oils

The volatile, fragrant components found in some plants are their essential oils. These clear, colourless, or pale yellow oils are extracted by distillation, by cold-pressing (expression), or by using organic solvents. Essential oils amount to approximately 1% to 2% of the weight of plant material. The amount varies depending on geographic location, weather conditions, soil type, and production and manufacturing techniques.

Essential oils contain several hundred chemicals, many of which are volatile and evaporate rapidly. Oils from unrelated plant species may have some ingredients in common. Structurally similar compounds may have different chemical properties. These oils can be contaminated with synthetic oils, pesticides, or herbicides and may degrade over time by exposure to oxygen, heat, moisture, or light. Thus, essential oils should be stored in a cool place in coloured glass bottles and should be used within one year of opening the bottle.

Many different essential oils are used in aromatherapy. Aromatherapy oils are mixtures of an essential oil and a carrier oil. The proportion of essential oil in such products could be as little as 4%.

Routes of Administration

The effect of essential oils also depends on the route of administration; this influences the proportion of the substance that reaches the systemic circulation. Methods of aromatherapy involve scent inhalation alone or in combination with massage. With massage, essential oils are applied directly to the body and massaged into the skin. Otherwise, essential oils are inhaled briefly as one might use smelling salts or in a more diffuse manner, as with incense or perfume. Oils may be dabbed on pulse points, dispersed by fragrance diffusers, simmered in potpourri vessels, added to boiling water to be diffused by steam, or added to a bath.

Skin

The rate of absorption through the skin differs with individuals, although it is influenced by evaporation and may increase with skin damage or disease. The amount of essential oil absorbed depends on the dilution of the oil, the amount of oil applied, and the total surface area of the skin to which the oil is applied. Higher skin temperature increases both absorption and evaporation, and hydration of the skin during a bath or shower increases the absorption of oils. There is evidence that massage enhances the absorption of some essential oil constituents through pressure and warming of the skin.

Inhalation

Odorous molecules in the air diffuse into the mucus layer of the nasal cavity and bind with receptors on the dendrites (nerve endings). There are over 1000 types of receptor proteins embedded in the dendrites that can stimulate the olfactory neurons to send a message to the brain. Since some chemicals may bind to more than one receptor type, the brain may perceive more than 1000 different odours from combinations of various olfactory neurons.

Inhaled substances also enter the lungs, where the small molecules of essential oils can pass into the blood. The amount of odoriferous molecules inhaled and reaching the blood depends on the rate of breathing.

Oral Administration

Taken orally, the dosage ranges between 0.5 and 2.5 mL per day; however, dosage and dilution are neither standardized nor measured with any precision.

All essential oils are fat soluble and tend to act like fat-soluble drugs in terms of distribution and metabolism. As essential oil molecules pass through the liver, they are metabolized by enzymes into molecules that are more water soluble.

The amount of essential oil that is absorbed orally is significantly greater than with inhalation or topical application. All cases of serious poisoning with essential oils have occurred with oral ingestion.

Actions and Clinical Applications of Essential Oils

The most common essential oils employed in aromatherapy are listed in Box 27.1 of the textbook (page 411). They are claimed to have a wide variety of beneficial actions on the body. The recommended amount of a particular essential oil is based on the philosophy of the practitioner prescribing the oil. Areas where this therapy is used are listed in Box 27.1 (page 410).

The mechanism of action of essential oils is not known with any certainty. The most likely mechanisms are pharmacological action through direct effects when oils enter the bloodstream, or psychological response when the aroma of the oil is inhaled.

Possible Hazards

Carried out sensibly, aromatherapy poses only a low risk of causing significant harm.

As with the administration of many other potentially toxic substances, those at greatest risk include babies, children, and pregnant women. Toxicity is dose dependent: the greater the amount of essential oil applied, the greater the risk of harm, with oral administration being the highest risk. In comparison, the amounts absorbed from inhalation are small. With a few exceptions, undiluted essential oils should never be applied to the skin. Poorly labelled essential oils should be avoided, and all oils should be kept out of reach of children.

Allergic reactions to the aromatic oils are the most serious risk of aromatherapy. The long-term effect of such inhalants on lung functioning is not well documented, and caution must be advised. The use of aromatherapy is contraindicated with any skin disorder such as severe eczema or psoriasis.

Users of essential oils should determine the contraindications for each oil and, if unsure of how to proceed, should take advice from a trained aromatherapist. Something that smells pleasant may not be harmless.

Is Aromatherapy Effective?

Aromatherapy has several similarities with homeopathy. With both there are an enormous number of combinations of treatments and conditions. This makes it hugely challenging to identify specific treatments that are effective.

More than a hundred research studies have been carried out on aromatherapy. Several systematic reviews of these studies have also been carried out. One group of researchers published an overview of these systematic reviews (Lee, Choi, Posadzki, & Ernst, 2012). One of the authors is Edzard Ernst; his negative assessment of homeopathy was quoted in the previous unit. Here is the abstract of this paper:

The aim of this overview was to provide an overview of systematic reviews evaluating the effectiveness of aromatherapy. We searched 12 electronic databases and our departmental files without restrictions of time or language. The methodological quality of all systematic reviews was evaluated independently by two authors. Of 201 potentially relevant publications, 10 met our inclusion criteria. Most of the systematic reviews were of poor methodological quality. The clinical subject areas were hypertension, depression, anxiety, pain relief, and dementia. For none of the conditions was the evidence convincing. Several systematic reviews (SRs) of aromatherapy have recently been published. Due to a number of caveats, the evidence is not sufficiently convincing that aromatherapy is an effective therapy for any condition.

Looking at this evidence as a whole, it is clear that more research is required, especially from well-designed randomized controlled studies. At the present time, we cannot state with great confidence that aromatherapy is effective for any particular condition.

Another obvious similarity between aromatherapy and homeopathy is that any benefit may well be due simply to the placebo effect. This is not necessarily a bad thing: if persons using aromatherapy feel better and the treatment is reasonably safe and cheap, then why not use it? In this respect aromatherapy is comparable to music therapy.

Learning Activity

Self-test Quiz

Do the self-test quiz for Unit 13 as many times as you wish to check your recall of the unit’s main points. You will get a slightly different version of the quiz each time you try it. (This quiz does not count toward your final grade).

If you have trouble understanding the material, please contact your Academic Expert.

Reference