Hydrotherapeutic Spa, Part VI: Aromatherapy, Healing Oils, and Bath Salts

The web page Robert McDowell's Herbal Treatments gives a very helpful overview of aromatherapy:

Essential oils stimulates the powerful sense of smell. It is known that odors we smell have a significant impact on how we feel. In dealing with patients who have lost the sense of smell, doctors have found that a life without fragrance can lead to high incidence of psychiatric problems such as anxiety and depression. We have the capability to distinguish an amazing 10,000 different smells. It is believed that smells enter through cilia (the fine hairs lining the nose) to the limbic system, the part of the brain that controls our moods, emotions, memory and learning.

Studies with brain wave frequency has shown that smelling lavender increases alpha waves in the back of the head, which are associated with relaxation. Fragrance of Jasmine increases beta waves in the front of the head, which are associated with a more alert state.

Scientific studies have also shown that essential oils contain chemical components that can exert specific effects on the mind and body. Their chemistry is complex, but generally includes alcohols, esters, ketones, aldehydes.

Each essential oil contains as much as 100 chemical components, which together exert a strong effect on the whole person. Depending on which component is predominating in an oil, the oils act differently. For example, some oils are relaxing, some soothes you down, some relieves your pain, etc. Then there are oils such as lemon and lavender, which adapt to what your body needs, and adapt to that situation. (These are called "adaptogenic"). The mechanism in which these essential oils act on us is not very well understood. What is understood is that they affect our mind and emotions.

It has been well established that chicken soup is good for a cold (both historically and scientifically). Studies were conducted to find out whether the effect was due to the action of the hot steam on the lining of the nostrils or whether the aroma of the chicken soup has some thing to do with it. The results indicated that chicken soup was more effective than the steam, indicating the effectiveness of the aroma itself.

The article, "Aromatherapy: What Is It?," by Jane Buckle, Ph.D., R.N., from HerbalGram: The Journal of the American Botanical Council, 2003;57:50-56, provides a superb "introductory course" in aromatherapy [I've deleted the footnote numbers in the text].

The definition accepted in most aromatherapy schools is, "Aromatherapy is the therapeutic use of essential oils." Essential oils are defined as volatile parts of aromatic plants extracted by steam distillation or expression.

Although one of the lesser-known complementary therapies in the United States, aromatherapy has been accepted as part of nursing care in the United Kingdom. British nurses are insured by the Royal College of Nurses to use essential oils (both topically and inhaled) for improved patient care, provided their hospital approves and without a doctor's specific instructions. Further, some hospitals also allow non-nursing personnel to use essential oils. Aromatherapy is also used by nurses in Australia, New Zealand, Canada, Germany, and Switzerland, and is becoming popular in the United States. More than 30 states allow the use of some complementary therapies (including aromatherapy) as a part of holistic nursing care.

. . . The confusion around what is, and what is not, aromatherapy may have occurred with the renaissance of aromatherapy in France and its export to England in the 1950s. French physicians used topical applications, ingestion, and inhalation, the method chosen according to its clinical appropriateness (e.g., inhalation for respiratory tract infections, or for psychological effect; ingestion for intestinal complaints; topical application for burns, skin, and muscular problems). These methods are clearly outlined in Aromatherapie (The Practice of Aromatherapy), a book first published in 1964 by Valnet, a French physician who used topical, oral, and inhaled applications of essential oils with his patients. Valnet documented the use of essential oils for wound healing and infection control. He wrote, "Essence of thyme [Thymus vulgaris L., Lamiaceae] destroyed the anthrax and bacillus and was a stronger antiseptic than phenol." . . .

Absorption of essential oil components through the skin

Jager et al showed that linalyl acetate and linalol, two components in essential oil of English lavender (Lavandula angustifolia Mill., Lamiaceae), were absorbed from a 2 percent dilution of English lavender in peanut oil through the abdominal skin of human subjects "within minutes" and detected in the blood plasma (ca. 10 ng/ml). The maximum level was attained at 20 minutes; even at 90 minutes, the two components could still be detected.

Fuchs et al demonstrated that (R)-(-)- carvone easily penetrated the skin of human subjects, producing a plasma concentration of 24—32 ng/ml after almost 30 minutes. Covering the skin produced a significantly higher effect. Twenty-five percent (R)-(-)- carvone in peanut oil was used. (R) carvone is an isomeric ketone found in caraway (Carum carvi L., Apiaceae). (L) carvone is found in spearmint (Mentha spicata L., Lamiaceae).

Wyers and Brodbeck demonstrated that 1,8 cineole was absorbed through the skin into the muscles. They found that when an applicator was used the absorption rate increased 320 percent.

In an email in June 2002, Buchbauer, who led much of the experimental work on topical absorption at the Institute of Pharmaceutical Chemistry, University of Vienna in Austria from the 1980s, is very clear, "It is now common knowledge that fragrance compounds are absorbed through the skin into the blood stream."

. . . because of its name, many people continue to think that aromatherapy is only about smelling something. That is incorrect. The usual definition is, "Aromatherapy is the use of essential oils for therapeutic purposes." No methods are suggested. But, clearly, only essential oils are used.

. . . Of the three methods of application (oral, topical, inhaled), inhalation has the most rapid effect. Chemical components within the essential oil bind to receptors in the olfactory bulb and have an almost instant effect on the hypothalamus and amygdala, which are located in the limbic part of the brain, where memory and smell are said to reside. Mills writes that the lipophyllic components in essential oils actually penetrate the blood-brain barrier. In animal experiments, Buchbauer showed that inhaled essential oil compounds could pass the blood-brain barrier and be detected in brain tissues (especially the cortex) of mice who inhaled single volatile fragrance compounds for 20 minutes.

Jager et al. reported an increase in the cerebral blood flow in the cortex of human subjects after inhalation of 1,8-cineole from an unspecified source. Similar studies by Nasel et al. found the increase not only in normal healthy subjects, but also with a woman with anosmia (the inability to smell). . . .

The importance of smell

The sense of smell is important to human beings throughout their lives. Babies use it to identify their mothers, and depression of elderly persons in residential facilities may be reduced by the smell of flowers. The scent of eucalyptus (Eucalyptus globulus Labill., Myrtaceae) can increase creativity, citrus, (Citrus spp., Rutaceae) may enhance immune function, lavender and clove (Syzygium aromaticum (L.) Merr. & L.M. Perry, Myrtaceae) can improve cognitive processing, and rose (Rosa spp., Rosaceae) and bergamot orange (Citrus bergamia Risso & Poit., Rutaceae) can be relaxing. Unfortunately, the source species is not always specified in the published literature.

Some essential oils have been found to have analgesic effects when inhaled, taken orally, or applied topically. Topically applied essential oils of lavender, Roman chamomile (Chamaemelum nobile (L.) All., Asteraceae), neroli (Citrus aurantium L., Rutaceae), mandarin (Citrus reticulata Blanco, Rutaceae), sandalwood (Santalum album L. Santalaceae), palmarosa (Cymbopogon martinii (Roxb.) J.F. Watson, Poaceae), and geranium (Pelargonium spp., Geraniaceae) were found to enhance pain relief in children with human immunodeficiency virus (HIV). Topically applied lavender was also found to be effective in reducing perceptions of pain in critical care settings.

West Indian lemongrass (Cymbopogon citratus (DC. ex Nees) Stapf, Poaceae) was shown to have topical analgesic effects and appeared to increase the effects of morphine. The component in West Indian lemongrass that produces the analgesic effect is myrcene, a monoterpene. Topically applied Roman chamomile reduced the perception of pain by patients with cancer in a randomized study by 51 patients. One of the patients in the study said, "I know most definitely that it [aromatherapy] has helped me in my quest for pain relief." In each of these studies, diluted essential oils were applied topically in a massage so it is difficult to extrapolate what analgesic effects are attributable solely to the essential oils. However, in a single case-study, inhaled damask rose essential oil (Rosa damascena Mill., Rosaceae) was found to be highly effective in reducing the perception of chronic pain in a patient with uncontrollable pain, despite patient-controlled morphine analgesia. Certainly it is the experience of the author and many of her students that essential oils can affect relaxation, and that in itself can alter the perception of chronic pain, making something that was unbearable, bearable. Candace Walsh, R.N., wrote, "I have come to understand that essential oils and touch can be a powerful part of any health package. They add an element of comfort and relief that promotes well being on the mental and emotional levels and can help to relieve pain."

Antimicrobial effects of essential oils

Possibly because aromatherapy is perceived to be useful mainly for stress, the antimicrobial properties of essential oils have not been acknowledged. Many essential oils have antibacterial, antifungal, and antiviral properties. Some in vitro studies have indicated that essential oils are effective against such bacteria as methicillin-resistant Staphylococcus aureus (MRSA), resistant Shigella, and resistant Escherichia coli bacteria.

[further specific examples provided, and the article concludes with 54 footnotes]

The University of Minnesota offers a page on aromatherapy. Some highlights:

From the sub-page, "How do Essential Oils Work?":

During inhalation, odor molecules travel through the nose and affect the brain through a variety of receptor sites, one of which is the limbic system, which is commonly referred to as the “emotional brain.”

The limbic system is directly connected to those parts of the brain that control heart rate, blood pressure, breathing, memory, stress levels and hormone balance (Higley & Higley, 1998). This relationship helps explain why smells often trigger emotions. Knowing this, we can hypothesize how inhalation of essential oils can have some very profound physiological and psychological effects!

And from "How Do I Choose and Use Essential Oils?" we find an application specifically relevant to the SG-2000 bubble massage spa:

. . . you can apply essential oils topically using compresses, sprays, baths, or massaging them into the skin. . . .

Bath: Drops of essential oils are added to bath water in a dispersant immediately before stepping in. This method results in absorption through the skin, as well as inhalation of the volatilized essential oil. A few tablespoons of full cream milk can be used as a dispersant.

Remember, essential oils are not water soluble; thus they will float on top of the bath and skin passing through the oil will be exposed to full strength essential oil. Bath salts can also be used to disperse essential oils. A relaxing bath base can be made by mixing 1 part baking soda, 2 parts Epsom salts, and 3 parts sea salt. Add 6 drops of true lavender essential oil to about 2 tablespoons of this mixture and mix it into bath water just before entering.

Another page on this website describes research currently taking place:

Although essential oils have been used therapeutically for centuries, there is little published research on many of them. However, this is beginning to change as more scientific studies on essential oils are conducted around the world.

Clinical studies are currently underway in Europe, Australia, Japan, India, the United States, and Canada. Many of these studies describe the remarkable healing properties of various oils.

. . . Research studies on essential oils show positive effects for a variety of health concerns including infections, pain, anxiety, depression, tumors, premenstrual syndrome, nausea, and many others. The articles included below are meant to highlight a few examples.

Anti-Microbial Effects

There is considerable international literature on the effects of essential oils against a wide range of bacterial, viral, and fungal microorganisms. Study results suggest that certain essential oils and components have strong bactericidal action, some even against antibiotic resistant microorganisms. Tea tree (Melaleuca alternifolia) oil in particular has a wide range of research studies that report its anti-microbial properties.

Click to download a PDF file of these research studies.

Pain
Some studies have been conducted on the use of aromatherapy for pain treatment. These studies suggest that essential oils may be effective for reducing discomfort during childbirth, headaches, gastrointestinal procedures, and for wound pain.

Click to download a PDF file of these research studies.

Psychological Effects

There are some studies on the psychological effects of essential oils. These studies suggest that essential oils may be effective for reducing anxiety and mild depression.

Click to download a PDF file of these research studies.

Toxicity and Sensitivity

Published reports suggest that a small proportion of individuals may develop sensitivity to topically applied essential oils. In addition, toxicity can result from accidental or intended ingestion.

Click to download a PDF file of these research studies.

Other Interesting Studies

There are other studies that examine the use of essential oils for such purposes as mosquito repellency, the potential to treat skin cancer, alopecia areata, and to affect glucose and insulin levels.

Click to download a PDF file of these research studies.

Expert contributor: Linda Halcon, Ph.D., M.P.H., B.S.N., R.N.

Created: March 2006

Other Resources

1) National Association of Holistic Aromatherapists

2) International Journal of Aromatherapy

3) International Council for Aromatic and Medicinal Plants (ICMAP)

4) AGORA, The Aromatherapy Global Online Research Archives

5) Essential Oils: Their Lack of Skin Absorption, but Effectiveness Via Inhalation (Martin Watt)

6) Aromatherapy Case Studies (Danila Mansfield)

7) FAQ Page (Michel Vanhove)

8) What is Aromatherapy and How Does it Work? (Martin Watt)

9) The Dangers of Some Essential Oils Sold on the Internet (Martin Watt)

10) Natural Toxins in Traditional Medicines - Some Myths Removed (Martin Watt)

11) Correcting the Gross Errors in Aromatherapy Teaching (Martin Watt)

12) Aromatherapy and Essential Oils Website

13) Aromatherapy Benefits: It Does More Than Just "Smell Good"

14) Aromatherapy Stress Relief

15) Which Problems can Aromatherapy Help? Results of Clinical Studies

16) A Beginner's "Essentials" [Oils]

17) Advanced Aromatherapy: The Science of Essential Oil Therapy, Kurt Schnaubelt, Ph.D. [book]

NAPRA Review Vol. 9, No.5 : "Schnaubelt brings singular authority to this explanation of the reasons why essential oils act on different systems of the body. This is aromatherapy's next generation, based in scientific analysis and structured to produce predictable results. Essential for the serious student." [Amazon]

18) Medical Aromatherapy: Healing With Essential Oils, Kurt Schnaubelt, Ph.D. [book]

19) Clinical Aromatherapy: Essential Oils in Practice, Second Edition, Jane Buckle [book]

James Barlow, Irish Pharmacy Journal, January 2005:

"The text is undoubtedly a progressive and ambitious work, and showcases the enthusiasm and experience of the author, and can be recommended to health professionals with an interest in the integration of conventional medicine with complementary and alternative therapies." [Amazon]