Jan. 26, 2009 -- Cutting calories may help older adults better remember items on a grocery list or the name of someone they just met, a study shows.
Researchers reporting in the Proceedings of the National Academy of Sciences found that older men and women who follow a restricted-calorie diet score better on verbal memory tests than those who do not make such diet changes.
Earlier animal studies have shown that low-calorie diets and those rich in "healthy" fats (called unsaturated fatty acids) may protect the aging brain.
Veronica Witte and colleagues at the University of Muenster in Germany say their results are the first to show that calorie restriction improves memory in older humans, too.
The three-month study involved 50 overweight men and women, with an average age of 60.5 years old. The men and women were separated into three groups:
- Group 1 reduced their calorie intake by up to 30%
- Group 2 changed their diet so it included more unsaturated fatty acids, such as olive oil and certain types of fish.
- Group 3 did not change their diet, and was considered the "control" group.
Clinical dieticians provided diet instructions. One person from the restricted-calorie group dropped out of the study.
After three months, those who cut calories had a significant increase in verbal memory scores, which included the ability to recall certain words on a list after several minutes had passed.
Those in groups 2 and 3 -- who did not cut calories -- did not show any significant memory improvements.
Blood tests performed on all study participants revealed lower insulin levels and markers of inflammation among the restricted-calorie group. Those who best followed the diet had the most pronounced changes in insulin and inflammation marker levels.
Study researchers think that improved insulin sensitivity and reduced inflammatory activity may play a role in improving memory, a theory they say requires further study, but could one day lead to a new realm of cognitive interventions.
"The present findings may help to develop new prevention and treatment strategies for maintaining cognitive health into old age," the researchers write.