Too Many Carbs Bad for the Brain

Dementia risk was increased for elderly people who got most of their calories from carbs

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) A balanced diet has many benefits, but replacing fats with carbs may increase risk of dementia.

A recent study looked at the types of calories elderly people were eating – fats, carbs and proteins – then tracked the people to see how diet related to risk of dementia.

They found that people with high carb diets were almost twice as likely to develop cognitive problems.

"Ask your doctor about ways to balance your diet."

Previous research has shown that high calorie diets increase risk of dementia. To look at this idea in more detail, researchers at the Mayo Clinic, led by epidemiologist, Rosebud Roberts, MB, ChB, looked for the possible influence of macronutrients on the risk of developing dementia.

Macronutrients are parts of food that provide most of the calories found in foods. They are carbohydrates, proteins and fats.

The researchers enrolled 937 elderly people who did not have any signs of mild cognitive impairment or dementia. At the beginning of the study, they were given neuropsychological assessments, tests of cognition, memory and thinking, and then every 15 months for up to four years.

At the start of the study, patients completed a questionnaire about their typical food intake including the types of food they ate and usual quantities.

The researchers calculated the percentage of calories that people got from carbohydrates, proteins and fats.

During the study, 200 people developed mild cognitive impairment or dementia.

The risk of dementia was almost double for people who got the highest percentage of their calories from carbohydrates.

People who got the highest percentage of their calories from fats and proteins showed a reduced risk of developing dementia.

In their abstract, the authors concluded that, “A dietary pattern with relatively high caloric intake from carbohydrates and low caloric intake from fat and proteins may increase the risk of MCI or dementia in elderly persons.”

The reasons that a high carb diet may increase risk of dementia are unknown. More research is needed.

The study was published July 17 in the Journal of Alzheimer’s Disease. Conflict of interest information was not available.

Reviewed by: 
Review Date: 
July 22, 2012
Last Updated:
March 18, 2013