Chewing has long been considered beneficial for digestion and nutrient absorption. But what you chew apparently could have a surprising impact on your brain too. A new study reveals that munching on harder foods, like wood, may boost memory and enhance brain health in ways softer foods can’t.
The findings, published in Frontiers in Systems Neuroscience, suggest that the act of chewing itself might have a direct influence on cognitive health. But chewing on harder foods can actually contribute a lot to your cognitive health. According to the researchers, chewing wood stimulated the formation of glutathione, a key brain antioxidant, more effectively than chewing gum.
How chewing affects brain
A study published in the International Journal of Medical Sciences noted that being able to chew properly is of utmost importance for elderly to maintain a healthy diet and preserve cognitive function. It has been found that the process of chewing is of great importance for peripheral sensory input to the hippocampus for preserving and promoting cognitive function.
In fact, tooth loss is a major risk factor for Alzheimer’s disease. BioMed Research International says chewing activates several brain regions that are essential for cognitive processing, including the hippocampus and prefrontal cortex.
The act of chewing can influence brain activity and blood flow. Brain requires a constant supply of oxygen and nutrients to function well, and blood flow can facilitate that.
Oxidative stress can damage brain cells which could lead to decline in cognitive function with age.
Brain uses certain antioxidants to protect itself, and one of them is glutathione. The researchers in this study aimed to find how chewing specific materials of hardness could affect glutathione levels and the memory and thinking skills.
How the study was carried out
The researchers involved 52 healthy university students in South Korea and divided them into two groups. One was asked to chew gum while the others were given small wooden sticks, similar to popsicle sticks to chew on.
Before and after five minutes of chewing, researchers used Magnetic Resonance Spectroscopy (specifically the MEGA-PRESS technique) to measure glutathione levels in the anterior cingulate cortex — a brain region linked to thinking and cognitive control. Participants either chewed paraffin wax gum or wooden tongue depressors, following a controlled chewing pattern. They also completed a cognitive test to assess memory, attention, and other thinking skills before and after the chewing session.
Researchers found that the group who chewed wood had a significant increase in glutathione levels. However, no significant change in the glutathione levels was noted in the group that chewed gum after chewing.
The wood chewing gum also performed better on memory tasks compared to the other group. In the gum-chewing group, no link was found between changes in glutathione and memory performance.
It was concluded that chewing wood seemed to both increase brain antioxidant levels and improve certain aspects of memory, and these two changes also seemed to be connected.
“In summary, this study yielded two major findings. Firstly, the wood-chewing group experienced stimulated of brain [glutathione (GSH)] synthesis, leading to increased GSH levels in the brain,” the researchers concluded. “Secondly, correlation analysis indicated that the higher GSH levels in the wood-chewing group were associated with improved scores in cognitive measures. Since there are currently no drugs or established practices for boosting brain GSH levels, our findings suggest that chewing moderately hard material could serve as an effective practice for increasing GSH levels in the brain. Based on these results, consuming harder foods might prove more effective in enhancing brain antioxidant defenses through elevated GSH levels.”