A cup of Joe in the morning is proving to do more for older adults than just providing a caffeine boost. Higher levels of caffeine in adults were shown to prevent the onset of Alzheimer's disease.

For adults over the age of 65 with slight memory impairment, just three cups of coffee a day may help reduce the risk of dementia and prevent the memory impairment from turning into Alzheimer's disease. That coffee habit you developed as an adult may be going a long way in preventing memory loss.

The study, led by Chuanhai Cao, from the University of South Florida's College of Pharmacy, indicated that 100 percent of coffee drinkers with mild cognitive impairment (MCI) did not develop Alzheimer's during the four year follow up of the study. Researchers focused on MCI because the patients are already suffering from some memory loss and approximately 15 percent of a patient's MCI will progress into Alzheimer's disease.

Many of the MCI patients will develop Alzheimer's and researchers wanted to determine if coffee could be beneficial for this group of patients who were most at risk. Blood was taken at the start of the study to measure caffeine levels in 124 individuals between the ages of 65 and 88. The participants were than observed for two to four years to determine the progress of cognitive impairment.

For MCI patients who later developed dementia, their blood caffeine levels, that were taken at the start of the study, were 51 percent less than MCI patients whose cognitive impairment remained stable. None of the MCI patients that developed dementia had caffeine levels that were equivalent to drinking several cups of coffee just hours prior to getting their blood taken, approximately 1200 ng/ml. More than half of the MCI patients whose impairment remained stable had caffeine levels higher than 1200 ng/ml.

For the MCI patients who did not develop dementia, coffee was really the only source of caffeine in their diet. The researchers believe that this is the "first direct evidence that caffeine/coffee intake is associated with a reduced risk of dementia or delayed onset, particularly for those who already have MCI."

In a previous study coffee was shown to help protect young adult Alzheimer's mice, which have the same protein as humans that causes Alzheimer's, from developing further memory impairment as older adult mice. According to the researchers, coffee may help Alzheimer's by suppressing two crucial enzymes that produce the abnormal protein. While coffee may feel like a necessity, especially when facing a long commute to work, now it could be invaluable for preserving your memory later in life.

The study was published in the Journal of Alzheimer's.