Dr. Giovambattista Desideri, director of the Geriatric Division at the University of L'Aquila in Italy, said the study involved 90 elderly people with mild cognitive impairment randomized to drink daily either 990 milligrams (0.035 ounce), 520 mg (0.018 ounce), or 45 mg (less than 0.002 ounce) of a dairy-based cocoa flavanol drink for eight weeks.
Sources of flavanols from other foods and beverages were restricted from the diet.
Cognitive function was examined by neuro-psychological tests of executive function, working memory, short-term memory, long-term episodic memory, processing speed and global cognition, Desideri, the study leader, said.
The study, published in the journal Hypertension, found:
-- Scores significantly improved in the ability to relate visual stimuli to motor responses, working memory, task-switching and verbal memory for those drinking the high and intermediate flavanol drinks.
-- Participants drinking daily higher levels of flavanol drinks had higher overall cognitive scores than those drinking lower-levels.
-- Insulin resistance, blood pressure and oxidative stress also decreased in those drinking high and intermediate levels of flavanols daily.
"This study provides encouraging evidence that consuming cocoa flavanols, as a part of a calorie-controlled and nutritionally balanced diet, could improve cognitive function," Desideri said in a statement. "The positive effect on cognitive function may be mainly mediated by an improvement in insulin sensitivity. It is yet unclear whether these benefits in cognition are a direct consequence of cocoa flavanols or a secondary effect of general improvements in cardiovascular function."