Chewing and the Hippocampus: What Is Actually Known About the Link to Memory

This article previously presented results from animal experiments as a story about preventing dementia in humans. It was rewritten in August 2026.

There is a claim that chewing well wards off cognitive decline. This article stated it as “demonstrated” and “clearly reported,” and closed by saying the paper “concludes that this is an extremely effective and safe intervention for maintaining the structural health of the brain without relying on drug therapy.”

The cited paper does not conclude that.

The Paper Behind the Claim

Chewing Maintains Hippocampus-Dependent Cognitive Function (PMC4466515) Chen H, Iinuma M, Onozuka M, Kubo KY. International Journal of Medical Sciences 12(6):502-509, 2015

This is a review. The authors did not run new experiments; they summarised earlier work. And most of the work they summarise was done in mice and rats.

What Has Been Reported in Animals

When chewing is reduced — by extracting molars, feeding only soft food, or disrupting the bite — reductions in hippocampal neurons and retraction of dendritic spines have been reported, along with worse performance on spatial memory tasks.

There are also reports that giving stressed animals something to chew restored the suppressed proliferation of hippocampal neurons and lowered the overactivity of the HPA (hypothalamic-pituitary-adrenal) axis.

That is all in animals. The authors themselves write that it is very difficult to single out any one model as the closest to the human condition, given that the human condition itself is not yet fully understood.

What Has Been Reported in Humans

The human research this review cites consists of epidemiological surveys and cross-sectional studies. They report an association: people with fewer remaining teeth or reduced chewing function show more cognitive decline and dementia.

No interventional trial that varied chewing and followed cognition in humans is included in this review.

This article previously stated that tooth count and reduced chewing function have “a strong causal relationship” with cognitive decline. Causality cannot be shown from cross-sectional data. The reverse explanation — that declining cognition leads to worse dental care — fits the same data equally well.

How the Authors Actually Phrase Their Conclusion

The paper’s conclusion reads:

Chewing might be an effective approach in maintaining hippocampus-related spatial learning and memory. Chewing may represent a useful approach in preserving cognitive function in older people.

“Might” and “may.” The sentence this article carried — that the paper “concludes it is an extremely effective and safe intervention” — was an assertion the paper does not make.

The authors also note there is a paucity of information on how the many substrates, neurotransmitter systems and genes involved interact.

What We Removed

“Demonstrated by recent neuroscience and brain image analysis” — this is a review, not a demonstration
“Playing a decisive role” — animal results were written as human results
“A strong causal relationship” — causality cannot be shown from cross-sectional studies
“A potential accumulating factor for future dementia risk” — this review did not track the onset of dementia
“An extremely effective and safe intervention for maintaining brain health without relying on drug therapy” — this contradicts the paper’s own conclusion, and no trial has compared chewing against medication

What Can Be Said Within the Evidence

In animals, reducing the opportunity to chew has been reported to affect hippocampal neurons and spatial memory
In animals, giving stressed subjects something to chew has been reported to restore hippocampal neuron proliferation
In humans, an association between tooth count or chewing function and cognitive function has been reported in cross-sectional studies
No human trial varying chewing and following cognition is included in this review
The authors’ conclusion is “might,” not a settled finding

Chewing your food well does no harm, and there are reasons to keep your teeth beyond chewing. But this is not at a stage where it can be recommended for the purpose of preventing dementia.

If You Are Concerned About Cognitive Function

If you are worried about forgetfulness, or a family member seems changed, please consult a memory clinic or a neurologist. This site has not identified a study showing that chewing can substitute for that.

This site introduces research on chewing and has not been reviewed by a medical professional.

This article is intended for informational purposes only and is not a substitute for diagnosis or treatment.