Genuine essential oils contain diverse complex substances comprising active ingredients, secondary components, and trace compounds. The oily volatile compounds are the result of plant metabolism and each plant has a particular organ for producing then storing an oil. The oil can be produced in the flowers, leaves, seeds, fruit, rinds, roots, or in wood like cedar. They are also found in grasses, herbs, needles, and branches of trees, in resin, balsam, and bark. The oils are extracted from the plant through a variation of distillation processes or by cold pressing. Different components can come from different parts of a single plant. Sometimes there are a number of varieties of the same plant; for example, there are hundreds of eucalyptus varieties throughout the world, each with a different oil, chemical composition, and therapeutic use.
The pharmaceutical effects of essential oils are due to their inherent chemical constituents and to the fact that these constituents work synergisti-cally. Their specific effects are determined by their structures, whether they have lipophilic or hydrophilic properties, and if they attract or repel electrons. They are so complex on the molecular level that one oil can have many different uses. The physical nature of oils, a low molecular weight, and an affinity for lipids or fats allow them to penetrate body tissues with great ease. When an oil is inhaled, it is absorbed in the nasal cavity and picked up by smell receptors that pass information to the limbic system of the brain where emotions and memory are controlled and
to the hypothalamus which controls digestion, heart rate, blood pressure, hormone balance, sexuality, and stress. Placed on the tongue or taken in gelatin capsules, the oil is absorbed along the digestive tract and travels to the liver where it is metabolized. Rubbing oils into the skin or inhaling them can be more effective delivery systems because they bypass liver processing. Massaging an oil into the feet is particularly efficacious.
High potency oils are expensive; however, they tend to be cost-effective because results can be obtained with smaller doses. The interaction of all the various compounds within an oil are qualitatively more effective than the isolation of a particular component or components. The oils can be inhaled, ingested, or applied topically. When delivered through a vaporizer, microparti-cles of the oil are dispersed into the air and inhaled. This system is effective for respiratory illnesses, to calm nerves, or to clear airborne infectious microbes. The oils can be used for massage, dispersed in the bath, mixed with water and sprayed into the air or on the skin, applied as a compress, or placed directly on the skin full strength or diluted with vegetable oil. When using a base or carrier oil for combining with the essential oil, use a cold-pressed unrefined vegetable, nut, or seed oil; essential oils can also be added to creams or lotions. Internal ingestion should be done only under the supervision of an aromatherapist. Essential oils can be toxic when taken internally; as little as one teaspoon of some oils can be fatal.
Aromatherapy is especially effective for infectious illnesses, for maintaining hormonal balance, and for psychological and nervous system conditions. Essential oils can harmonize moods and emotions and alter brain waves in such a manner as to have a tranquilizing effect that produces a sense of well-being and calm. Certain oils act as stimulants and have an energizing effect. Treatments may be less effectual for diseases that are genetic or have been chronic for a number of years; metabolic and degenerative illnesses may not respond at all. Extensive studies, many of which have been conducted in Germany, have shown the beneficial effects of essential oils. For example, as antibacterial agents, certain oils were found to prevent the spread, and eliminate the presence, of a number of pathogens including E. coli, Streptococcus, Staphylococcus, and Candida albicans in an enclosed room.5 Their ability to prevent microorganism proliferation in the body may be through their ability to penetrate cellular membranes and influence cell metabolism. At the same time, they do not destroy valuable intestinal flora as conventional antibiotics tend to do.
Certain essential oils have antiviral properties, act as expectorants for respiratory ailments, have sedative and antispasmodic qualities, and give support to the immune system. Some oils have an effect on the autonomic nervous system, moderating an overactive sympathetic system. In a clinical study, 80% of the participants reported positive improvement for symptoms affecting the nervous system including depression, tension, headache, fatigue, insomnia, and loss of appetite.6 Some oils have shown in studies to have an anti-inflammatory effect by stimulating the adrenal glands and releasing cortisone-like substances. Brain waves were shown to be altered on another group who experienced improved visual search tasks.
The manner in which the oils are taken is very important. Sometimes oral ingestion has no effect while inhalation presents clear results. If doses are too high, a secretion-stimulating effect reverts to a secretion-inhibiting one. The most effective dosages are usually the lowest (1 mg per kilogram of body weight), while raising the dosage reduces efficacy. An individual weighing approximately 150 lb would normally use between two and five drops. In a clinical study, blood samples were taken from participants after they had inhaled certain essential oils. Therapeutic levels of the compounds were found but within an hour levels decreased by half, showing that the oils did not accumulate in the blood.7
Some essential oils can cause a reaction in certain individuals who are susceptible to allergies. To test for potential sensitivity, place a small amount of oil on the inside of the elbow for 24 hours. If no reaction is evident, it is advisable to repeat the process in 20 to 48 hours. Certain oils are to be used either externally or internally exclusively; some can exacerbate or complicate existing health conditions; and yet others are poisonous, although those are not usually available commercially.
Ketones are the toxic elements in essential oils and these molecules can penetrate the blood-brain barrier causing damage to the nervous system and irreversible liver damage. The ketone most widely found in oils is thujone, a component in mugwort, sage, thuja, wormwood, and yarrow oils. Although sage oil has a high content of the ketone, it appears to have low toxicity and can be used by adults with caution. The toxic effects of ketones depend on how it is administered; inhalation being the safest, followed by skin contact, vaginal, rectal, and oral ingestion.
Anise, atlas cedar, eucalyptus dives, yarrow, clary sage, chamomile, pennyroyal, and rosemary oils are not to be used during pregnancy; spike lavender and niaouli, which have hormone-like properties, should be used with caution. Fennel oil stimulates the production of estrogen and is not to be used if an individual has breast cancer or if there is a family history of the disease. Basil and possibly tarragon oils can be carcinogenic in large quantities. Thuja, wormwood, mugwort, tansy, and hyssop are toxic when taken internally. Pine is not to be used internally. Hyssop and thuja should be administered only in small doses externally. Pennyroyal is poisonous in large doses. Savory and oregano dosages are not to exceed three drops taken internally and not to be used for more than a 21-day period. Oregano, thyme, and savory are not for external use; although thyme and oregano are well tolerated if rubbed into the soles of the feet. Internal use of thyme should not exceed three drops per day. Clove oil, clove leaf oil, cinnamon bark oil, and cinnamon leaf oil can cause skin irritation and may cause swelling of the entire body and severe shortness of breath in susceptible individuals. Bergamot, bitter orange rind, khella, lemon, and mandarin should not be applied to the skin. Juniper oil can be damaging to the kidneys whereas the berries of the juniper are not irritating. Crested lavender, anise, atlas cedar, basil, cinnamon, eucalyptus dives, eucalyptus globulus, rosemary, sage, and yarrow are not suitable for children. Niaouli and peppermint should be used with caution. Spike lavender should be mixed with benign oils. Camphor induces abortion and is toxic to the nerves.
If the following health conditions are present do not take the listed oils:
Asthma—marjoram, oregano, rosemary, yarrow Breast cancer—angelica, anise, caraway, cypress, fennel, sage
Epilepsy—anise, fennel, hyssop, nutmeg, parsley, sage
Glaucoma—cypress, hyssop, lemon balm, tarragon, thyme Hemorrhaging—lavender if taking an anticoagulant
High blood pressure—hyssop, lemon Hypothyroidism—fennel Insomnia—peppermint, pine Menstrual complaints—angelica, anise, caraway, cypress, sage Prostate cancer—angelica, cypress, hyssop, Thymus serpyllum Tumors—anise, caraway, fennel Urinary tract infection—eucalyptus, juniper
For more information contact: National Association for Holistic Aromatherapy, P.O. Box 17622, Boulder, Colorado 80308-0622, 303-258-3791; Lotus Light, P.O. Box 1008, Wilmot, Wisconsin 53170, 414-889-8501; The Pacific Institute of Aromatherapy, P.O. Box 6842, San Rafael, California 94903, 415-479-9121.
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