Portuguese researchers report that a study suggests that drinking three to four cups of coffee a day over the course of an adult lifetime provides enough caffeine to reduce the risk of Alzheimer's disease by as much as 60 percent.

Their report in the European Journal of Neurology said that a study of 108 patients -- half with Alzheimer's disease -- found that healthy persons had consumed at least three cups of coffee daily since age 25, while those with Alzheimer's had consumed on average one cup of coffee a day.

"If confirmed, this finding should have a major impact on the prevention of Alzheimer's," the researchers from the Faculty of Medicine in Lisbon said.

The researchers found that the study participants without Alzheimer's had consumed an average of 200 milligrams of caffeine daily, while those with Alzheimer's had consumed an average of 74 milligrams of caffeine a day.

Scientists believe it is the caffeine -- which can be derived from different quantities of a number of other beverages as well -- that protects against Alzheimer's.

Other Sources: European Journal of Neurology