Drinking coffee regularly can lower the risk of developing Alzheimer's, a new study has revealed. Scientists, who tracked elderly patients over a four-year period, found those with the highest levels of caffeine in their bloodstream at the start of the study were less likely to suffer the brain-wasting disease, the Daily Mail reported. Researchers at the University of South Florida found that volunteers who remained healthy had twice as much caffeine circulating in their systems as those who progressed to the early stages of dementia. The findings support previous studies that revealed drinking three cups of a coffee a day could considerably reduce the risk of the incurable illness. Researchers believe that caffeine may work by triggering a chain reaction in the brain that prevents the damage done by Alzheimer's. "This case-control study provides the first direct evidence that caffeine/coffee intake is associated with a reduced risk, or delayed onset, of dementia," the researchers said. The study has been published in the Journal of Alzheimer's Disease.