The quality of carbohydrates in the diet plays a key role in the prevention of dementia

The quality and quantity of carbohydrates in the diet play a decisive role in the development of dementias. This is according to a combined study carried out by the Nutrition and Metabolic Health (NuMeH) research group of the Universitat Rovira i Virgili (URV), the Centre for Environmental, Food and Toxicological Technology (TecnATox), and the Pere Virgili Health Research Institute (IISPV). The results of this research have been published in the scientific journal International Journal of Epidemiology.

Although one of the primary risk factors for developing dementia is age, maintaining a healthy lifestyle—and especially a balanced diet—also play an essential role in reducing cognitive decline and promoting healthy ageing. Carbohydrates are the main component of the diet and account for approximately 55% of the total energy we consume. Due to their role in glucose and insulin metabolism, both the quantity and the quality of the carbohydrates we consume significantly influence our metabolic health and risk of related diseases, such as Alzheimer’s.

One of the key indicators is the glycaemic index (GI), which measures how quickly carbohydrates raise blood glucose after consumption. The scale—from 0 to 100—classifies foods according to whether they cause more or less rapid increases: foods such as potatoes or white bread have a high GI, whereas most fruits and whole grains have a low GI.

To reach their conclusions, the team analysed data from a study of more than 200,000 adults in the United Kingdom who did not have dementia at the start of the process. Using questionnaires, they were able to assess the glycaemic index and glycaemic load of each participant’s diet. After an average follow-up of 13.25 years, it was found that a total of 2,362 people developed dementia. Through advanced statistical techniques, the researchers determined at what levels of the glycaemic index the risk of developing dementia began to increase, allowing them to obtain a very precise picture of how diet can influence long-term brain health.

The results showed that consuming foods with a lower glycaemic index is associated with a lower risk of developing dementia, whereas higher values increase the risk. Specifically, diets with a low to moderate glycaemic index were associated with a 16% reduction in the risk of developing Alzheimer’s, whereas higher values were associated with a 14% increase in risk.

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

These results highlight the importance of taking into account both the quantity and quality of carbohydrates in strategies aimed at preventing and managing dementia.