The news that chewing gum could potentially boost brain power has hit the headlines. Both the Daily Mail and the Daily Express covered the story, with the Mail reporting that, "Chomping on gum is good for the brain and can boost alertness by 10%."
However, this claim is based on what is actually a very small study involving just 17 healthy young adults. Such a small sample size means that the results of the study need to be viewed with caution.
Most of us can walk and chew gum at the same time. This study does not prove that gum chewing will help us think any faster.
Where did the story come from?
The study was carried out by researchers from the National Institute of Radiological Sciences (NIRS) and other academic research centres in Japan. It received funding from the Japanese Ministry of Education, Culture, Sports, Science and Technology, and by Research Fellowships for Young Scientists from the Japan Society for the Promotion of Science (JSPS).
It was published in the peer-reviewed medical journal, Brain and Cognition.
The study was covered reasonably by the Daily Express and the Daily Mail, although neither reports that such a small number of people (17) were included.
What kind of research was this?
This was an experimental study looking at whether chewing has an effect on attention and cognitive processing speed (the ability to think quickly).
The researchers say that other studies have found varying results when exploring the link between chewing and cognitive functions such as attention.
The study was carried out in a research laboratory under controlled conditions, carrying out very specific tasks.
What did the research involve?
The researchers enrolled 19 healthy adults, aged 20 to 34 years. Two of the volunteers were not included in the analysis because they had moved during functional MRI (fMRI) scanning.
Volunteers were asked to perform a cognitive task that involved watching a computer screen that flashed images of a row of five arrows pointing either left or right. Sometimes all of the arrows pointed in one direction and sometimes they pointed in mixed directions.
The volunteers had to press a button with their left or right thumb depending on the direction the middle arrow pointed. In some cases, a central "cue" marker was shown before the arrows appeared to warn the volunteer that the arrows were coming.
The volunteers performed this task both while chewing gum and not chewing gum, with researchers recording the speed and accuracy of the button presses. During the chewing phase, messages on the computer screen instructed volunteers to chew for 10 seconds every six images, just before the test.
The volunteers' brains were monitored using functional MRI (fMRI) while they performed the tasks. This technique shows blood flow in the brain, with increased blood flow indicating more activity in a specific region of the brain.
The researchers assessed whether reaction time and accuracy differed when chewing gum. They also assessed whether there were any differences in brain activity during the chewing and non-chewing tasks.
What were the basic results?
The researchers had mixed results in the fMRI analysis, with some areas of the brain thought to be involved in alertness and movement becoming more active, while others did not.
They found that chewing did cause some areas of the brain, such as the anterior cingulate cortex, to become more active, but the overall results were inconclusive. Some areas of the brain also associated with alertness actually became less active during chewing.
A similar inconclusive pattern was found when fMRI was used to study areas of the brain involved in "executive function" (in this case, working out which direction the arrow pointed in).
They also found that reaction time was quicker when a person was chewing gum, but their accuracy did not change.
How did the researchers interpret the results?
The researchers concluded that chewing reduced reaction time in their cognitive test. The brain scan results suggest that this could be due to increased alertness and an effect on movement control.
They also suggest that chewing gum could possibly make volunteers more relaxed, which could improve alertness and reaction time.
This study has suggested that chewing gum may improve reaction times in healthy adults in a specific computerised cognitive task. The study only assessed 17 healthy relatively young adults, and the results may not apply to other groups of people.
Most importantly, this specially designed cognitive experiment was performed in a laboratory environment, and may not represent what would happen in a real-world setting. For example, we can't say for certain whether people's reaction speeds when driving a car would be improved by chewing gum.
The study may be of interest to some researchers, but at the moment it does not have any obvious practical implications for people's health or day-to-day lives.
A final word of advice: if you do choose to chew, make sure your gum is sugar-free, which is the healthiest option for your teeth.
Analysis by Bazian
Edited by NHS Website
Links to the headlines
Daily Mail, 3 February 2013
Daily Express, 4 February 2013
Links to the science
Brain and Cognition. Published online January 29 2013