Less carbohydrates, less memory

Massachusetts, United States, December 13: Excluding carbohydrates from routine diet may help you shed weight and lower cholesterol level, but it could rob your memory, a new study suggests.

Scientists from the psychology department at Tufts University warned that dieters who cut out high energy foods such as pasta, bread and potatoes could end up losing their memory skills.

Professor Holly Taylor of Tufts University, in Massachusetts, who led the study, believes the reason behind these findings could be due to the way human brain uses glucose, a type of sugar obtained from carbohydrates in food, as a form of fuel.

As glucose cannot be stored in mind, it needs a constant supply of the sugar to power our brain cells. So a reduced carbohydrate intake means less fuel to power the brain cells, the researcher explained.

"Although this study only tracked dieting participants for three weeks, the data suggest that diets can affect more than just weight," Taylor said in a news release. "The brain needs glucose for energy and diets low in carbohydrates can be detrimental to learning, memory, and thinking."

To reach their findings, Prof. Taylor, in collaboration with Professor Robin Kanarek, former undergraduate Kara Watts and research associate Kristen D'Anci, carried out a study in which they included 19 women between the ages of 22 to 55, who were told to select either a low- carbohydrate weight loss plan similar to Atkins diet or the low-calorie diet recommended by the American Dietetic Association that includes plenty of fruits, vegetables, and whole grains.

The Atkins diet is a high-protein, high-fat, and very low-carbohydrate regimen that emphasizes meat, cheese, and eggs, while discourages consumption of foods such as bread, pasta, fruit, and sugar. This low-carbohydrate diet is a form of ketogenic diet, and is characterized by initial rapid weight loss, usually due to water loss.

Nine study participants chose a low-carbohydrate diet and ten selected the low-calorie diet.

After a one-week follow up, Taylor and colleagues found that low-carb dieters who ate virtually no carbohydrates during their first week on the diet performed more poorly on memory-based tasks than the women following the ADA diet.

"The data suggest that after a week of severe carbohydrate restriction, memory performance, particularly on difficult tasks, is impaired," Taylor said.

Their cognition skills returned to normal after week one, when limited carbohydrates were reintroduced into their diets, she said.

"This study demonstrates that the food you eat can have an immediate impact on cognitive behavior. The popular low-carb, no-carb diets have the strongest potential for negative impact on thinking and cognition," Taylor added.

The findings will be published in the February 2009 issue of the journal Appetite.