The type of carbs you eat may affect dementia risk

While age remains one of the strongest risk factors for dementia, researchers emphasize that lifestyle choices also play an important role. A healthy routine, particularly a well balanced diet, can help slow cognitive decline and support healthier aging. Carbohydrates make up the largest share of most diets, providing about 55% of daily energy intake. Because carbohydrates directly affect blood sugar and insulin levels, their quality and quantity can have a major impact on metabolic health and diseases linked to brain function, including Alzheimer's.

Why the Glycemic Index Matters

A key focus of the study was the glycemic index (GI), a measure of how quickly carbohydrate containing foods raise blood glucose levels after eating. The GI scale -- from 0 to 100 -- ranks foods based on this response. Items such as white bread and potatoes score high, meaning they cause rapid spikes in blood sugar, while foods like whole grains and most fruits score lower and lead to slower increases.

To investigate long term effects, researchers examined data from more than 200,000 adults in the United Kingdom who did not have dementia when the study began. Participants completed detailed questionnaires that allowed scientists to estimate the glycemic index and glycemic load of their regular diets. Over an average follow up period of 13.25 years, 2,362 participants were diagnosed with dementia.

Using advanced statistical methods, the research team identified the point at which higher dietary glycemic index values were linked to increased dementia risk. This approach helped clarify how long term eating patterns may shape brain health later in life.

Lower Glycemic Diets Linked to Reduced Risk

The analysis revealed a clear pattern. Diets centered on lower glycemic index foods were associated with a reduced likelihood of developing dementia, while higher GI diets were linked to greater risk. People whose diets fell into the low to moderate glycemic range showed a 16% lower risk of developing Alzheimer's. In contrast, diets with higher glycemic values were associated with a 14% increase in risk.

"These results indicate that following a diet rich in low-glycemic-index foods, such as fruit, legumes or whole grains, could decrease the risk of cognitive decline, Alzheimer's and other types of dementia," said study leader Mònica Bulló, who is a professor in the URV's Department of Biochemistry and Biotechnology, a researcher at ICREA, and director of the URV's TechnATox Centre.

Implications for Dementia Prevention

Overall, the findings underscore the importance of paying attention not only to how many carbohydrates people consume, but also to the type they choose. Incorporating carbohydrate quality into dietary strategies may be an important step in reducing dementia risk and supporting long term brain health.