SAN FRANCISCO--Researchers at the annual meeting of the American Association for the Advancement of Science last month said a special type of cocoa could help maintain brain function and stave off cognitive decline and dementia as people age.

In a session called "The Neurobiology of Chocolate: A Mind-Altering Experience?," Ian Macdonald, a professor at the U.K.'s University of Nottingham Medical School, said a brain imaging study he conducted suggests that flavanols--a naturally occurring nutrient found in fresh cocoa--may improve blood vessel function, thus increasing brain blood flow and "enhancing brain function among older adults."

After study participants drank a flavanol-rich cocoa beverage from Mars Inc., their brains showed increased blood flow for a two-to-three-hour period, Macdonald said. He noted this raises the possibility that increased blood flow might benefit older adults and those who have cognitive impairments like fatigue or sleep deprivation.

In a separate U.S. study, Harvard Medical School researcher Norman Hollenberg said he observed a "striking blood flow response" that evolved over several weeks after healthy volunteers over age 50 were fed the special Mars cocoa.

Hollenberg said he found similar benefits in the Kuna Indians of Panama, who drink natural cocoa rich in flavanols on a daily basis. In addition to low rates of cardiovascular disease and cancer, there are no reports of dementia among the Kuna, he said.

While it's still too early to conclude that cocoa leads to better health, the scientists cautioned, more research is warranted.