Aromatherapy

Overview of Aromatherapy

Aromatherapy is the practice of using highly concentrated essential oils to change your mood, reduce symptoms or improve health [1]. Essential oils are extracted from different plants or flowers. They have been used for thousands of years for bathing, cosmetic and medicinal purposes in different cultures across the globe.

In recent years there has been growing scientific interest in aromatherapy with potential therapeutic applications to help cancer patients manage certain disease-associated symptoms. Essential oils can be applied in a variety of ways. They can be rubbed into the skin in weaker dilutions with a carrier oil. Drops of essential oils can be put into bath water or inhaled if put into steaming water, diffusers or inhalers. Aromatherapy is also often used in combination with massage.

There are a wide range of different essential oils used in aromatherapy including lavender, tea tree, lemon, ginger, cedarwood, bergamot, geranium and many more [2]. Each type of essential oil has a specific chemical make-up, which dictates its smell, absorption and effect on the body [2]. It is believed that aromatherapy works by affecting scent receptors in the nose, which in turn can modulate heart rate, blood pressure, breathing, lower stress and trigger pleasant feelings and memories [3]. Through the sense of smell, aromatherapy may communicate with and stimulate parts of the brain that produce feel good chemicals such as serotonin and dopamine, which can have calming effects and reduce pain [3].

In recent decades, as aromatherapy has become more widely studied and accepted as a complementary therapy it has even been incorporated into the hospital setting. Established programs in many hospitals implement aromatherapy and report benefits for stress, pain, anxiety, depression, nausea, vomiting, and other symptoms that are common amongst cancer patients [3]. However, benefits tend to be short-lived. More rigorous scientific research is still needed to better understand mechanisms of action and confirm clinical efficacy for all claimed benefits.

Historical Perspective of Aromatherapy

The first documented use of aromatic herbs dates back to before Christ when used for religious ceremonies, embalming dead bodies, treating certain diseases, therapeutic baths and massage [1]. Aromatic or essential oils also have been used for thousands of years as stimulants or sedatives of the nervous system and as treatments for various different disorders [4]. There are documented references of infused oils and unguents being used as remedies in the Bible, ancient Egypt, throughout the Middle Ages and the Renaissance period [4].

The history of modern aromatic oil therapy originates in the early twentieth century when French chemist and perfumier Rene Gattefosse coined the term “aromatherapy”as a subcategory of herbal medicine [1]. Gattefosse published a book in 1937, which claimed that aromatherapy could be used to treat diseases in almost all systems in the body, primarily citing anecdotal evidence and case studies (isolated reports with small sample sizes) as a basis for his claims [4].

Although Gattefosse and colleagues studied aromatherapy for over 30 years the practice went out of fashion by the middle of the century [4]. Aromatherapy was later rediscovered by another Frenchman and physician Jean Valnet [4]. Valnet published a book The Practice of Aromatherapy in 1982, which garnered global attention [4]. As a result, the therapy became more well-known in Britain and the United States in the latter part of the century [4]. Throughout the 1980s and 1990s cancer patients started to become ever more interested in complementary and alternative therapies [4]. This helped to bring awareness to aromatherapy and it continues to grow in popularity as a supportive treatment modality to this day [4].

There was very little scientific research on aromatherapy in the English language until the 1990s, at which point more studies began to appear in the literature. A dedicated scientific journal for aromatherapy now exists called the International Journal of Essential Oil Therapeutics. Many studies have been published on the therapeutic effects of smell on our brain, psychology and neurobiology [4].

Research supporting Aromatherapy

There is currently a significant body of scientific research on aromatherapy for a range of problems commonly experienced by cancer patients [3]. Clinical trials using aromatherapy have studied its application as a treatment for anxiety, nausea, vomiting, depression, poor sleep and other disease or treatment related symptoms [2] [3]. To date, no studies have been carried out in peer-reviewed journals on aromatherapy as an anticancer treatment in its own right [2]. Overall, the research has shown mixed results in terms of managing symptoms, but potential positive effects have been documented. More high-quality studies are needed to confirm efficacy in symptom management.

A 2004 randomized controlled trial on aromatherapy massage with lavender oil involving 42 cancer patients in the palliative care setting revealed that it had positive effects on improving sleep [5]. A 2017 study showed benefits of aromatherapy with lavender, peppermint and chamomile for insomnia in 50 patients with acute leukemia [6]. The treatment had a statistically significant positive impact with improvements noted in tiredness, drowsiness, lack of appetite, depression, anxiety, and general well-being [6].

A 2022 meta-analysis (statistical analysis and summary of prior research) on the effects of inhaled aromatherapy in cancer patients analyzed data from 11 different studies involving over 2500 patients [7]. It concluded that inhalation aromatherapy appeared to be effective in improving the symptoms of depression and anxiety, and may be more effective than aromatherapy massage. However, effects were only short-lived. The researchers called for more high-quality studies as the current literature does not yet support clinical implementation for depression or anxiety.

A 2017 study showed that ginger aromatherapy had a significant effect on chemotherapy-induced nausea and vomiting in 60 cervical cancer patients [8]. In the study, patients inhaled ginger essential oil for a period of 10 minutes and results revealed that the severity of nausea was significantly lower compared to control groups. The researchers indicated that ginger aromatherapy could be applied as an alternative medication to reduce post-chemotherapy nausea and vomiting. A 2021 review corroborates these results with statistically significant benefits reported for chemotherapy-induced nausea and vomiting in numerous studies using various types of essential oils [11].

Other studies have had more mixed results. A double-blind trial (participants and researchers unaware of treatment given) of inhalation aromatherapy, including 313 cancer patients undergoing radiation treatments, did not reveal any benefits of aromatherapy for anxiety levels [9]. A 2021 randomized controlled trial (participants chosen at random) on lavender aromatherapy in 49 women undergoing breast reconstruction with clinical anxiety and/or depression did not show any improvements in symptoms of anxiety, depression, pain, and sleep [10].

Further clinical research is still needed to better understand the effects of aromatherapy and potential clinical applications. However, current research does indicate that it may have benefits for some cancer patients in the management of certain disease-related symptoms.

Potential Applications of Aromatherapy

There has been significant research published on the effects of different odors on the human brain and emotions they can invoke [4]. Studies have shown that essential oils can affect mood, alertness and mental stress in patients [4]. Research has consistently shown that different odors can produce specific effects on the human brain, psychology and modulate the function of the autonomic nervous system with potential therapeutic applications for stress and adverse psychological conditions [4].

There are different theories on exactly how aromatherapy with essential oils works. More research is needed to accurately define the different mechanisms of action and explain exactly how aromatherapy produces its therapeutic benefits. Proponents of aromatherapy claim that the connection between the olfactory system (related to smell) and limbic system (related to behavior and emotions) in the brain is the basis for how aromatherapy affects mood and emotions [4].

However, less is known about the mechanisms of action behind its effects on other parts of the body. It is believed that the effects of the treatment are based on the special properties of the complete essential oils and that the effects they produce are greater than the sum of any individual chemical component in the scents [4].

Large hospital studies have shown that aromatherapy with lavender or sweet marjoram may help to alleviate anxiety in cancer patients [3]. It has been shown that cancer patients suffering from anxiety felt noticeably more relaxed and less stressed when using an aroma inhaler [3].

Aromatherapy massage has been shown in one large trial to have clinically significant benefits on depression among cancer patients that lasted up to two weeks after treatment [3]. However, in the case of massage other factors such as the music, surroundings and therapist work synergistically to reduce symptoms [3].

Ginger has been shown in many studies to have beneficial effects for reducing nausea and vomiting when administered via aroma inhalers [3]. It has also been demonstrated to provide benefits in terms of increasing appetite and improving overall health scores in patients [3].

Several studies have shown that aromatherapy can help to improve sleep problems in cancer patients and reduce fatigue [3]. The benefits related to fatigue are thought to be primarily linked to improvements in sleep quality as studies on aromatherapy that specifically address fatigue have had mixed results [3].

Aromatherapy, notably with the use of sweet marjoram, has been shown in the literature to provide potential benefits in reducing pain for cancer patients [3]. Research indicates that aromatherapy can trigger the release of feel good chemicals in the brain such as dopamine and serotonin, which can produce calming effects and reduce levels of pain experienced [3].

Risks and Side Effects of Aromatherapy

Overall, aromatherapy with essential oils is considered to be safe. Many different aromatic oils are used as food additives and are generally recognized as safe by the U.S. Food and Drug Administration [1]. However, there are a few possible adverse effects.

The most common side effect when essential oils are applied topically is a skin reaction, rash or hives. Some essential oils such as lavender, bergamot and others can make your skin more sensitive to sunlight and cause photosensitive dermatitis [3]. Ylang-ylang, lemongrass, jasmine, sandalwood, and clove oils have been known to cause skin sensitivity in certain people [3].

There have been reports of peppermint oil causing mouth sores, while frequent application of lavender and tea tree oil products to the skin have been linked to abnormal breast growth in pre-teen boys [3].

Essential oils should not be ingested and can be poisonous when swallowed.