IJE: Excess “Fast” Carbohydrates Increase Dementia Risk by 14%

A diet dominated by “slow” carbohydrates reduces the risk of developing dementia, while foods that sharply raise blood sugar levels increase the likelihood by 14%, according to researchers from Rovira i Virgili University. The results of this large study were published in the International Journal of Epidemiology (IJE).

The study included over 200,000 adult residents of the UK, who were followed for an average of 13 years. Participants’ diets were assessed using the glycemic index—a measure of how quickly foods raise blood glucose levels. During the follow-up, cognitive impairments were diagnosed in 2,362 participants.

The analysis showed that diets with low to moderate glycemic index reduced the risk of Alzheimer’s disease by 16%. The researchers explained that fruits, whole grains, and legumes raise blood sugar more gradually. In contrast, a high-glycemic diet—dominated by white bread, potatoes, and refined foods—increased the likelihood of developing dementia by 14%.

“For brain health, not only the amount of carbohydrates matters but also their quality. ‘Fast’ carbohydrates affect glucose and insulin metabolism, which are closely linked to neurodegenerative changes,” the study authors noted.

The researchers emphasized that shifting toward low-glycemic foods may be a simple and accessible strategy for dementia prevention and reducing the risk of cognitive decline in older age.