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DAEGU, South Korea — Your brain and your jaw might have a closer relationship than you think. While we’ve long suspected that chewing affects brain function, new research has uncovered a surprising biological connection: chewing on hard materials for just five minutes can boost levels of glutathione, the brain’s primary antioxidant defense system. Could the texture of what you chew actually matter for brain health? Science is starting to say yes.

Researchers from several South Korean universities made a fascinating discovery: participants who chewed on wooden sticks for just five minutes showed measurable increases in glutathione (GSH) levels in their brain. Even more intriguing, this increase was associated with improved memory function, suggesting that something as simple as vigorous chewing could have meaningful benefits for brain health.

“Chewing moderately hard material elevates brain antioxidant levels such as GSH, potentially influencing cognitive function,” concluded the research team, led by scientists from Kyungpook National University. Their findings were published in the journal Frontiers in Systems Neuroscience.

While previous research had established connections between chewing and increased blood flow to the brain, this study breaks new ground by uncovering a potential biochemical mechanism behind chewing’s cognitive benefits. The research suggests that chewing harder materials might offer a practical, accessible way to boost brain antioxidant defenses—something potentially valuable for everyone from students cramming for exams to older adults concerned about cognitive decline.

Why is GSH so valuable to the brain?

Brain health researchers have long known that our brains are particularly vulnerable to oxidative damage. The human brain consumes approximately 20% of the body’s total oxygen while containing high levels of fatty acids that can easily be damaged. Moreover, the brain accumulates metals like iron, copper, and zinc that can promote the formation of harmful reactive oxygen species.

Against this backdrop, glutathione serves as the brain’s primary defense system. GSH is often called the “master antioxidant” because of its crucial role in protecting the brain against oxidative stress—a major contributor to cognitive decline and various neurodegenerative diseases. When GSH levels fall, brain cells become more vulnerable to oxidative stress, which has been linked to everything from normal aging to serious conditions like Alzheimer’s disease.

Normally ranging from 1 to 3 millimolar (mM) in concentration in adults, GSH helps neutralize harmful molecules called reactive oxygen species (ROS) that can damage brain cells.

“The brain is especially vulnerable to oxidative stress,” note the researchers. “Therefore, the finding that chewing hard materials increases GSH concentration is intriguing and significant because it suggests that mastication may help protect the brain from oxidative stress.”

Through vigorous chewing—particularly on harder materials—we might naturally boost our brain’s antioxidant defenses without the need for supplements or medications. Scientists know that chewing increases blood flow to the brain and activates various brain regions, but this study suggests that the mechanical properties of specifically what we chew might be just as important as the act of chewing itself.

Chew wood, not gum?

The research team recruited 52 university students and divided them into two groups: one that chewed paraffin wax gum and another that chewed wooden tongue depressors. The chewing protocol was carefully standardized: participants chewed at a rate of one chew per second, alternating between 30 seconds of chewing and 30 seconds of rest, all while lying in an MRI scanner. Using brain imaging technology, researchers measured glutathione levels in participants’ brains before and after five minutes of chewing.

The distinction between soft gum and harder wooden sticks proved crucial. While gum-chewing produced no significant change in brain GSH levels, wood-chewing increased GSH concentration from an average of 1.22 mM to 1.37 mM—a statistically significant jump.

While the gum-chewing group showed no significant change in brain GSH levels, the wood-chewing group demonstrated a meaningful increase in GSH concentration in the anterior cingulate cortex (ACC), a brain region important for cognitive control. Even more remarkable was the positive correlation found between these GSH increases and scores on immediate memory and story memory tests in the wood-chewing group.

This connection between chewing hardness, antioxidant levels, and cognitive performance opens exciting possibilities for both everyday brain health practices and potential approaches for conditions associated with oxidative stress in the brain.

More compelling still was the connection between these GSH increases and cognitive performance. In the wood-chewing group, the rise in GSH levels showed a positive correlation with immediate memory scores and story memory scores. No such correlation appeared in the gum-chewing group, suggesting that the hardness of the chewed material plays a meaningful role in cognitive benefits.

For students, the findings suggest that chewing something firm during study sessions might potentially enhance memory formation. For aging adults concerned about cognitive decline, incorporating more challenging chewing into their routine might offer some protective benefits for brain health.

Speak to your doctor first

Currently, there are no approved therapeutic drugs specifically designed to increase brain GSH levels. Orally administered GSH gets broken down in the digestive system, while intravenously administered GSH is rapidly oxidized in the bloodstream. The discovery that chewing hard materials can naturally boost brain GSH levels offers a potential non-drug approach to enhancing brain antioxidant defenses.

Of course, no one is suggesting you start gnawing on pencils or wooden spoons just yet. As with any preliminary research, these findings need further testing across broader populations and age groups. The researchers themselves acknowledge several limitations, including their small sample size and focus on young, healthy university students.

Talk to your doctor first before heading out to the store for a package of tongue depressors to chew on, and be sure to ask about the potential risks involved, especially if you have sensitive teeth or other oral hygiene issues. And we’d suggest to be fully aware of pieces of wood breaking off in your mouth. The last thing anyone wants is a splinter in their throat!

It may be wiser to consider the potential benefits from incorporating more texturally challenging foods into our diets—think crunchy vegetables, nuts, tough whole grains, and fibrous proteins that require more vigorous chewing. If chewing harder foods could help maintain higher GSH levels, it might represent a simple, accessible strategy to support cognitive health in later life. Now go ahead and chew on that!