Aromatherapy is not included in the arsenal of modern medicine, its destiny is beauty salons, massage rooms. Nevertheless, scientists are trying to understand how smell affects behavior, mood, and human physiology. RIA Novosti talks about what the science of fragrances has achieved.
In ancient China, vegetable essential oils were burned to fumigate premises, the Egyptians added them to solutions for embalming the dead, the Romans took them with them to the baths. But science has taken up this relatively recently. The term "aromatherapy" was coined in the 1920s by the French chemist Rene-Maurice Gattefosse.
Plants certainly contain nutrients. For example, willow bark has been chewed since ancient times to treat inflammation, and then acetylsalicylic acid, now known as aspirin, was found in it. But it is one thing to take pills, and quite another to inhale. How to confirm that a scent has a therapeutic effect? What is the physical mechanism of action? In aromatherapy, only subjective descriptions are given that cannot be verified. For example, it is reported that the scent of rosemary clears the mind and improves memory, lavender soothes and relieves stress, anxiety, depression, and insomnia. Juniper oil has been found to have 17 beneficial effects, from aphrodisiac to sedative.
The Science of Fragrances
Since the 1980s, a new scientific direction has been developing - aromachology, that is, the study of how smells affect physiology and health. In 2007, American scientists analyzed all the articles that published data on the healing effects of odors. Only 18 of them were recognized as available for scientific analysis, and even then with certain reservations. It is difficult to conduct such studies, because there is a lot of subjective in them, it is unclear how the experimental technique affects the result, and, most importantly, it is not known what is the mechanism of the effect of odor on the body.
Perhaps the molecules of the aromatic substance directly affect the olfactory neurons and then the brain or the endocrine system. Either chemical substances enter the bloodstream through the nose or the lining of the lungs and then spread throughout the body. This is confirmed by experiments on rodents, in which molecules of inhaled essential oils were found in the blood. In other experiments, rats calmed down by inhaling cedrol, a component of cedar, although their sense of smell was damaged. Of course, treatment with odors would be convenient, because the effect after inhalation is immediate, and the dose of the substance is required much less than when taking pills. But in order to develop scientifically based aromatherapy, you need to understand the mechanism of action of the smell, and this is still a long way off.
Interesting results were obtained by the experiments of scientists from Austria with linalool, the main component of lavender oil. When it was applied to the skin of the participants in the experiment, their systolic blood pressure (upper) dropped slightly. This can be considered an analogue of massage, but the fact that massage itself soothes and relieves tension prevents the recognition of the therapeutic effect of essential oil.
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In Russia, the project "Influence of the odor environment on the physiological status and cognitive processes of a person" is supported by the Russian Science Foundation. Its participants are from the A. N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, the Institute for Information Transmission Problems named after A. N. AA Kharkevich and Oryol State University found out that the smells of lavender and mint improve the memory of schoolchildren aged 10-11 years. Analysis of the participants' saliva before and after the experiment showed that inhaling peppermint was the most likely to reduce levels of the hormone cortisol, which regulates stress. Since it is known from other studies that high levels of cortisol in the body weaken memory, it means, scientists conclude, that mint relieves stress.
Continuous emotions
All the observed effects can be explained differently - through psychological influence. That is, a person reacts to smell according to his experience and expectations, as well as through training. This hypothesis is supported by the fact that people experience emotions, change behavior in accordance with whether the smell is pleasant or not. For example, customers in a supermarket that smells good are more likely to help other customers. Company employees also work better, set themselves higher goals, if the room smells good.
Another factor is preconceived notions. When 90 female students were told that the pleasant smell in the room was relaxing, their heart rate and skin conductivity did indeed decrease, even though they sprayed only lavender and neroli oil from orange. All the students noted that their mood improved. They said the same thing, having been in a room with a placebo, that is, with an odorless substance.
Proponents of the psychological hypothesis believe that the chemical nature of the smell is secondary, the main thing is the mental effect. To some extent, this is evidenced by cultural, individual and even gender differences in the perception of smells. For example, in men who walked in the forest for three days in a row, the level of the hormone adrenaline decreased. There is also evidence that aromatherapy can relieve depression. In general, so far the psychological hypothesis of aromatherapy is better supported by experiments.
Regardless of whether aromatherapy is scientific or not, it should not be forgotten that the components of essential oils can cause allergies, especially with prolonged exposure.
