Aromatherapy oils are relied upon to relax, reduce stress and soothe aches and pains by many. However researchers from Chia-Nan University of Pharmacy and Science Tainan, Taiwan say these oils may not be completely harmless.
They found that the aromatherapy oils can react with the air to produce tiny irritant particles. And when they are used for massages, the concentration of these potentially harmful particles can increase tenfold.
The scientists say that certain chemicals in the oils, called volatile organic compounds, mix with the air to form secondary organic aerosols. These particles irritate the eyes, nose and throat and are also known to cause headaches, nausea and damage to the liver and kidneys.
This study only examined the size of particles released when people had massages in spas, but other research has shown that they are also produced from burning essential oils, although not to the same extent.
Taiwanese researchers Der-Jen Hsu (National Kaohsiung First University of Science and Technology), Hsiao-Lin Huang (Chia-Nan University of Pharmacy and Science, Tainan), and Shiann-Cherng Sheu (Chang-Jung Christian University, Tainan) tested both fragrant and Chinese herbal essential oils for SOA formation in a controlled-environment study chamber under different test conditions. They also performed air sampling and analysis in spa centers that offer massage therapy using essential oils.
Among the oils the ones that generated the highest number of aerosols were lavender, tea tree, eucalyptus, lemon and peppermint. These oils are thought to have a number of benefits including boosting the immune system and helping with sleep, but the scientists say that the negative effects should not be overlooked. They noted that some of these oils can aggravate breathing problems in those with lung disease and to increase symptoms of asthma.
The study, published in the journal Environmental Engineering Science, measured the volumes of certain secondary organic aerosols when oils were rubbed in during massages in two spas in Taiwan.
The scientists concluded, “As aromatherapy, used by the general public and some health institutes, has become one of the most popular complementary therapies, its impact on indoor air quality and health effects cannot be neglected. Volatile organic compound degradation caused by the reaction of these compounds with ozone present in the air can produce small, ultrafine by-products called secondary organic aerosols which may cause eye and airway irritation.”
They added, “We compared secondary organic aerosol levels associated for the various fragrant and herbal essential oils tested and conclude that the layout and ventilation within a particular spa may affect the level of indoor air pollutants produced during massage with aromatherapy.”
“Dr. Der-Jen Hsu and his colleagues have done a very nice job in bringing attention to often overlooked health risks associated with luxuries intended to enhance our sense of well-being,” says Domenico Grasso, Editor-in-Chief and Vice President for Research, Dean of the Graduate College, University of Vermont (Burlington).
Britons spend around £126million on aromatherapy products and herbal medicines every year. Sceptics argue that many of the perceived benefits of the oils are caused by a placebo effect – and people just convince themselves they feel calmer and more relaxed. They also say there is little scientific evidence that they can relieve pains, cure wounds or boost immunity.
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