In pop culture, chewing gum has long been a signature trait of effortlessly cool, self-assured protagonists. Think Danny Zuko and the Pink Ladies in Grease, the rebellious supervillain Harley Quinn in DC comic books films, or popular school girl Cher Horowitz in 90s comedy Clueless. It’s an aesthetic that remains in our culture as a daily commodity and, love it or hate it, the UK chewing gum market is estimated to include more than 28 million consumers using it for their minty fresh breath. As a nation, we are the fifth-largest consumer globally.
But the science of its benefits go far beyond the cool factor or its use as a palate cleanser after a tuna sandwich. Beyond the breath, the pillow-shaped confectionery has deeper psychological effects: stretching to improve memory, stress, and focus. Recent revelations also show there is more than meets the eye to the refreshing sensation some gums offer – making it more than just an opportunistic marketing ploy.
Yoshiyuki Hirano, a Professor at Chiba University in Japan, has been a leading researcher into the effects of chewing gum for more than two decades. His work consistently points to the idea that the science behind the cognitive benefits are based less in the contents of the product itself, and more from the sustained chewing action it enables.
“The rhythmic motion of chewing stimulates the reticular activating system in the brainstem,” Hirano explains, referring to the part of the brain which is responsible for dealing with sleep cycles and alertness. The muscles used for chewing – or mastication, to use the academic terminology – have been shown to send nerve impulses to this area, which push it into a more alert state.
“Chewing similarly increases heart rate and cerebral blood flow,” he adds, “Both of which are believed to contribute to enhanced cognitive performance.”
To illustrate this, one study conducted by Hirano and his colleagues in 2008 used an MRI machine to monitor the brain activity of participants completing a cognitive assessment. The “n-back” test, during which they had to recall photographs from a sequence, is designed to test working memory and information recall. The scan results showed a “significant activation” of the dorsolateral prefrontal cortex, which is a region of the brain which holds and processes information. When it came to the test, the accuracy of participants’ recall was also noted to improve after chewing.
By no means did this indicate a dramatic shift in focus, but it did show a marginal improvement that can be enough to enhance attention and focus when working through tedious tasks, long meetings, or study sessions, all without the need for a caffeine hit.
Stress reduction
The scientific evidence is not limited to focus either. Chewing has also been shown to have stress-alleviating effects, such as suppressing the release of the stress hormone cortisol and reducing feelings of anxiety. Work by another leading researcher in the field, Cardiff University‘s Andrew Smith, concluded groups of university students with high and low workloads both reported lower levels of perceived stress after chewing gum for just twenty minutes per day.
Hirano’s research has gone on to prove this as well. “Even in a stressful environment like an MRI scanner – which is noisy and confined – chewing gum can help maintain a positive mood and protect cognitive performance,” he says.
Research into the subject goes back as far as the American Professor Harry Hollingworth in 1939, who touted chewing gum as a relaxation technique and a “tension outlet”.
One reason for this is believed to be a greater blood flow to the prefrontal cortex part of the brain, which regulates stress, anxiety, and other emotions. This then helps to regulate a glandular system which includes the adrenal, pituitary, and neighbouring hypothalamus glands (known as the HPA axis) to control stress responses.
The ingredients
Many brands are aiming to capitalise on this by marketing ingredients and flavours designed to stimulate further “focus” or “energy boosts”. It is part of a rapidly growing market for functional chewing gum – expected to be worth $3.76bn by 2030. This includes gums for jaw strengthening and relaxation, as well as for enhancing brain function. Additives often include vitamins and caffeine for an extra boost.
But when it comes down to reinvigorating flavours, such as strong mint flavouring, evidence indicates the effects of this are mostly insignificant in relation to the primary changes to brain function. To prevent a placebo effect, Hirano’s research has used tasteless and odorless gums to isolate benefits solely to the chewing motion. Without any flavour, the cognitive benefits are still there – therefore, chewing remains the main driving force.
So does it matter what else is added to the gum? “The most significant advantage of chewing gum is that it allows for sustained chewing,” he says. “Unlike regular food, gum does not need to be swallowed, meaning a person can maintain a steady, rhythmic chewing motion for an extended period. This continuous rhythm is particularly effective for maintaining arousal and sustained attention.”
That said, flavour and scent aren’t completely redundant. He clarifies some can have secondary effects to “further stimulate the brain”. Although this is through an increase in low-frequency brain waves called beta-waves.
The cool factor
Alongside easing stress, chewing gum can have a genuine refreshing effect. That’s right, the laid-back, calm persona of chewing gum users that’s presented on screen is not a total work of fiction.
In 2002, scientists David Julius and Ardem Patapoutian discovered a sensory receptor known as TRPM8 – work for which they won the Nobel Prize for Medicine in 2021. The receptor sits within membranes of sensory neurons supplying the skin, mouth, and eyes, and responds when exposed to temperatures roughly between 7 and 27 degrees celsius. When stimulated, it opens up, allowing a chemical trigger to fire a nerve signal to the brain.
It’s not only the cold that TRPM8 reacts to though – it has the same response to minty ingredients like menthol. And it wasn’t until research released last year that scientists were able to see why this happened.
“We visualized how humans feel cold for the first time,” explains Hyuk-Joon Lee, co-author of the study and a postdoctoral fellow at Duke University in North Carolina. “For a long time, we knew that it happened, but we didn’t know how. Based on this research, we could not only deepen the understanding of the receptor, but also resolve a fundamental question in sensory biology.”
Using a microscope that observes cells in a frozen state, the researchers captured snapshots of TRPM8 transitioning from cold to open, illustrating the similarities in how it was similarly stimulated by both cold and menthol. Hence, the refreshing sensation the ingredient provides.
“Menthol is like a trick,” Lee adds, “It attaches to a specific part of the channel and triggers it to open in the same way cold temperatures do. So we can see that even though menthol isn’t actually freezing anything, your body still receives the same signal that it would if it were touching ice.”
And it’s not just menthol too. Other common ingredients used in chewing gum, such as eucalyptus, were among substances TRPM8 is “very amenable to” – a discovery that “could give insights into development of newly cold sensation-inducing foods or drinks”.
This isn’t the only encouraging prospect for future research. Hirano speaks of “compelling” findings indicating that chewing gum could be a potential preventative measure for senile dementia.
Ages of benefits
In a study, participants in different age groups were again observed chewing through an MRI scanner. Results showed older test subjects exhibiting an “intense activation” of the right prefrontal cortex, which manages working memory and emotions.
“While brain activity often declines with age, we found that chewing increased activity in the right prefrontal cortex of elderly subjects by approximately four times compared to younger subjects,” Hirano recalls. “This suggests the brain adapting to recruit more resources to maintain brain function, highlighting chewing’s potential role in dementia prevention.”
The motion has also been shown to “warm up” the hippocampus region – the first area to be targeted by dementia – suggesting chewing can suppress some signs of degeneration.
The ability to chew gum can also decline with age, loss of teeth, and other dental issues. The impact of that and the way teeth fit together is going to be a “vital area for future exploration”, Hirano says.
Of course, chewing gum is not the ultimate brain food or a miracle medicine. In fact, its usual effects are largely short-term and modest. As Hirano explains: “The cognitive enhancement is largely tied to the temporary arousal generated by the movement, making the effect short-lived. Once the stimulation to the brainstem stops, arousal levels return to baseline. Generally, these benefits last for about 15 to 20 minutes after chewing.”
However, what we can say is that it is more than an aesthetic, more than something to keep your dentist happy, and more than something to stop your last meal hanging around on your breath. The science shows the next time you’re looking for something to help you concentrate, reaching for a pack of gum is something worth chewing over.
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