Poor oral health may increase the risk of dementia through both biological and social mechanisms, according to researchers from the Institute of Science Tokyo.
In addition to biological effects like inflammation, oral health problems such as chewing and speaking difficulties may contribute to social isolation, which is also linked to cognitive decline.
As people age, oral health tends to decline if not properly maintained. Common issues include tooth loss, dry mouth, and jaw weakness, all of which can interfere with eating and communication. These issues not only reduce quality of life but may also have broader impacts on physical and mental health.
Previous studies have shown a connection between poor oral health and dementia. While the exact direction of this relationship is still unclear, most research has focused on biomedical explanations—like inflammation and oral bacteria affecting the brain. However, recent research highlights a new factor: the social aspect of oral function.
Professor Jun Aida and colleagues conducted a literature review and found that difficulties with eating and speaking may play a key role. These functions are crucial for social interaction.
When impaired, they can lead to loneliness and isolation—both known risk factors for dementia. Thus, poor oral health could indirectly increase dementia risk through its social consequences.
In addition to reviewing past studies, Aida’s team conducted a six-year study of more than 3,000 older Japanese adults. They found that chewing difficulty was the most significant predictor of weight loss, suggesting that oral frailty can seriously affect nutrition and overall health.
These findings highlight the need for better oral care among older adults—not only to protect their teeth but also to support brain health, nutritional wellbeing, and social connection. Early interventions may reduce the risk of cognitive decline and improve quality of life.
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The study is published in the Journal of Dental Research.
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