If you have symptoms prompted by everyday smells, it does not necessarily mean you are allergic but rather that you suffer from chemical intolerance. According to Linus Andersson at Umeå University, this hypersensitivity can be the result of an inability to get used to smells.
Normally your smell perceptions diminish rapidly, as when you enter a friend’s apartment. Even though you clearly notice smells just inside the door, you don’t think about them for long. For people with chemical intolerance, on the other hand, smells seem always to be present. Psychology researcher Linus Andersson has exposed both intolerant and non-intolerant individuals to smells and compared their reactions.
“The hypersensitive individuals felt that the smell was getting stronger even though its concentration had not changed. Their brain activity images also differed from those in the other group,” he says.
Differences in brain activity
The results were observed using methods based on both electroencephalography (EEG) and functional brain imaging technology (fMRI). The EEG method involved placing electrodes on the heads of trial subjects and registering the minute changes in tension in the brain that arise following exposure to smells. Unlike the people in the normal group, Linus Andersson explains, the intolerant people did not evince a lessening of brain activity during the period of more than an hour they were exposed to a smell. The inability to grow accustomed to smells is thus matched by unchanging brain activity over time.
“These individuals also have a different pattern in the blood flow in their brains, compared with those who perceive that a smell diminishes. A similar change can be found in patients with pain disorders, for example.”
Sensitivity to smell impacts the entire body A further finding in the dissertation is that chemical intolerant people also react strongly to substances that irritate the mucous linings of their nose and mouth. People who cough more when they inhale capsaicin, the hot compound in chili peppers, also have heightened reactions in the brain to other smells. Besides the fact that intolerant individuals perceive that smells grow stronger, effects are also seen in mucous linings and in the brain.
“In other words we can see indications that this intolerance affects both the body and the mind, and that it’s important not to blindly focus on just one of these aspects,” says Linus Andersson.
Chemical intolerance is surprisingly common – up to ten percent of the Swedish population report they are bothered by everyday smells, whereas roughly two percent experience severe symptoms. Yet, in contrast to the situation regarding allergies and asthma, there is very little research about what causes this condition. Linus Andersson maintains that if it were possible to identify what characterizes this hypersensitivity then it would be possible to develop methods for diagnosis and treatment. But research can also provide new knowledge about how we should think about our work and everyday environments.
“Some co-workers are bothered more than others by the smell of the printer — what should we do to make our working conditions acceptable to as many people as possible?”
Dissertation: Sick of Smells: Empirical Findings and a Theoretical Framework for Chemical Intolerance.
Linus Andersson, Department of Psychology, Umeå University
phone: +46 90 786 64 28
More articles from Health and Medicine:
Answers to Sleep Disorder and new paradigm for treatment and mechanism of neurodegenerative disease
21.05.2013 | Ulsan National Institute of Science and Technology (UNIST)
Child maltreatment increases risk of adult obesity
21.05.2013 | King's College London
University of Würzburg physicists have succeeded in creating a new type of laser.
Its operation principle is completely different from conventional devices, which opens up the possibility of a significantly reduced energy input requirement. The researchers report their work in the current issue of Nature.
It also emits light the waves of which are in phase with one another: the polariton laser, developed ...
Innsbruck physicists led by Rainer Blatt and Peter Zoller experimentally gained a deep insight into the nature of quantum mechanical phase transitions.
They are the first scientists that simulated the competition between two rival dynamical processes at a novel type of transition between two quantum mechanical orders. They have published the results of their work in the journal Nature Physics.
“When water boils, its molecules are released as vapor. We call this ...
Researchers have shown that, by using global positioning systems (GPS) to measure ground deformation caused by a large underwater earthquake, they can provide accurate warning of the resulting tsunami in just a few minutes after the earthquake onset.
For the devastating Japan 2011 event, the team reveals that the analysis of the GPS data and issue of a detailed tsunami alert would have taken no more than three minutes. The results are published on 17 May in Natural Hazards and Earth System Sciences, an open access journal of ...
A new study of glaciers worldwide using observations from two NASA satellites has helped resolve differences in estimates of how fast glaciers are disappearing and contributing to sea level rise.
The new research found glaciers outside of the Greenland and Antarctic ice sheets, repositories of 1 percent of all land ice, lost an average of 571 trillion pounds (259 trillion kilograms) of mass every year during the six-year study period, making the oceans rise 0.03 inches (0.7 mm) per year. ...
About 99% of the world’s land ice is stored in the huge ice sheets of Antarctica and Greenland, while only 1% is contained in glaciers.
However, the meltwater of glaciers contributed almost as much to the rise in sea level in the period 2003 to 2009 as the two ice sheets: about one third. This is one of the results of an international study with the involvement of geographers from the University of Zurich.
21.05.2013 | Studies and Analyses
21.05.2013 | Life Sciences
21.05.2013 | Studies and Analyses
17.05.2013 | Event News
15.05.2013 | Event News
08.05.2013 | Event News