MOSCOW, August 13, Salma Sultanova. Recent studies have revealed the beneficial effects of odors on health, mental state, sleep, memory. At the same time, data are accumulating about the dangers of synthetic and some natural flavors. How exactly volatile compounds affect the body is not completely clear. Scientists put forward several hypotheses.
What does nature smell like
We smell when molecules of a substance enter our nose. There, the epithelium has olfactory receptors. The incoming information is encoded by electrical signals and transmitted by clusters of nerve cells (glomeruli). The mitral cells then send it to the brain for analysis and recognition.
The smell not only causes sensations, emotions, but also affects well-being. Almost two hundred volunteers in the UK inhaled the scent of wet grass, rain, and campfire smoke in parks in different seasons, and then filled out a questionnaire. Most noted that their mood improved, they relaxed and calmed down. Smells are often associated with memories. For example, the scent of fallen leaves makes us happy because as children we used to play with friends in the forest.
Scientists from Germany and France gave 139 healthy women and men nose clips that smelled of orange, fresh lemons, melons ( hydroxycitronellal), as well as floral and musky perfumes. An odorless clamp was also included. They were used every night, and the next morning they filled out a sleep diary. The most rested were those who found the aroma especially pleasant.
In another study, Swedish and Danish psychologists followed patients with stress disorders in the Alnarp Rehabilitation Garden. Over the course of five years, they interviewed those who completed the 12-week treatment program there.
Most of all, the patients liked pelargonium, a flower of the geranium family. Its citrus aroma relieved stress, promoting mental recovery. Natural smells reminded of childhood and caused joy. But the perfume suggested thoughts about stressful situations at work, the hospital smell — about the hospital. Smoke was associated with danger. =»600″ data-crop-height=»379″ data-source-sid=»» class=»lazyload» lazy=»1″ />
Does aromatherapy work
Treatment with smells, or aromatherapy, has been used for more than one millennium. The main remedy is essential oils obtained by steaming, pressing various parts of plants. It is believed that these oils act on the central nervous system indirectly (through olfactory receptors in the epithelium of the nose) and directly, since volatile compounds are able to enter the bloodstream, breaking the blood-brain barrier.
Korean scientists analyzed experiments where they recorded the electrical activity of the brain, and found that essential oils enhance alpha rhythms. Lemon, lavender, sandalwood, jasmine, ylang-ylang, rose and mint promote concentration and improve mental well-being. In addition, lavender stimulates theta activity in all areas of the brain in women — this helps with insomnia.
Chinese experts also made a review on aromatherapy and concluded that essential oils are useful for depression, anxiety and mental disorders. In a number of studies, this has been confirmed by clinical studies and animal experiments. It is assumed that volatile compounds reach neurons through the bloodstream and affect the cerebral cortex, thalamus and limbic system. Unlike psychotropic drugs, aromatherapy does not cause side effects.
Researchers from Thailand have noted that orange oil increases efficiency if a diffuser is installed in the office. And lavender, chamomile, bergamot, sweet orange, anise, geranium and mountain pepper alleviate depression and anxiety disorders in the elderly, women after childbirth, and simply restless patients.
Memory effects
In the United States, a recent olfactory enrichment experiment was conducted among older people aged 60 to 85 without cognitive impairment. Each was given a diffuser and seven cartridges of essential oils of rose, orange, eucalyptus, lemon, mint, rosemary, lavender.
One group (20 people) received fully charged cartridges, the second (23) — with trace amounts of active ingredients. In the evening, the subjects inserted a new cartridge into the diffuser, and it was activated for two hours while they slept. Before and after the experiment, cognitive abilities were measured using a memory vocabulary test, and a functional head MRI was performed.
In the first group, cognitive abilities increased by 226 percent and, according to self-reports, sleep became better. fMRI scans have shown that people have improved the condition of the uncinate fasciculus of the brain, which connects the cerebellar amygdala and the orbito-frontal cortex. This is the main path of the limbic system, which is responsible for emotions and memory. The results obtained will help with age-related disorders, including dementia, scientists are sure.
Who the smell is harmful to personal hygiene is a completely different matter. People complain of asthma attacks, headaches and other unpleasant symptoms.
According to a study by Anne Steinemann from the University of Melbourne, published in 2017, one in three people experience problems due to artificial fragrances in the home. Most often they indicate breathing difficulties, mucosal inflammation, migraines, skin rashes, asthma. -crop-ratio=»1″ data-crop-width=»600″ data-crop-height=»600″ data-source-sid=»rian_infographics» class=»lazyload» lazy=»1″ />
Later added data from the US, UK and Sweden. In general, the conclusions were confirmed. In addition, sometimes sensitivity to smells turns into a loss of work.
Flavors are a complex mixture of chemical contaminants, some of which are carcinogenic. Probably people react to them, especially indoors. It is not yet clear how exactly these volatile compounds cause painful symptoms. Perhaps something will become clearer when manufacturers are required to disclose the exact composition of household chemicals.
Kate Granville, author of The Case Against Fragrance, calls perfumes and fragrances a «minefield» for allergy sufferers.
Ian Musgrave, professor of pharmacology at the University of Adelaide, believes that some essential oils are also toxic. For example, beta-damascenone, which is found in roses and also smells like bourbon, can cause allergic reactions, while 1,8-cineole from eucalyptus can damage the liver. we don't know yet.