U. S. researchers said caffeine consumption may help treat or even prevent Alzheimer's disease based on two new study results.

Researchers at the University of South Florida said back-to-back studies showed brains and blood of mice exhibiting symptoms of Alzheimer's to show significantly decreased levels of the protein linked to the disease with caffeine.

The studies published in the July 5 online edition of the Journal of Alzheimer's Disease, reported that brain levels of beta amyloid, the protein linked to characteristic plaque found in human Alzheimer's disease, was significantly reduced with caffeine.

In a news release lead author Gary Arendash, a University of South Florida neuroscientist said, "The new findings provide evidence that caffeine could be a viable 'treatment' for established Alzheimer's disease, and not simply a protective strategy."

"That's important because caffeine is a safe drug for most people, it easily enters the brain, and it appears to directly affect the disease process."

Florida researchers said that a daily 500 milligrams of caffeine, the equivalent found in five 8-ounce cups of coffee was found to reverse memory issues in mice bred to develop Alzheimer-like symptoms.

In the study, mice were genetically altered to develop memory problems mimicking Alzheimer's disease. Half of the 55 mice were given caffeine, and the other half was given water. At the end of the two-month study, it was seen that the caffeinated mice performed much better on tests that measured their memory and thinking skills and the mice scored as well on memory tests as normal mice of the same age that had never exhibited signs of dementia.

Previous research at the Florida Alzheimer's Disease Research Center in Tampa, where these studies were done, linked caffeine consumption in early adulthood to preventing memory problems from occurring in these specially bred mice. The reason is possibly due to the stimulant's ability to calm the brain inflammation that causes beta amyloid levels to rise.

Caffeine was also found to reduce beta amyloid levels in elderly people without dementia just as quickly as it does in the mice bred to have Alzheimer's symptoms.

Arendash said consuming 500 milligrams of caffeine a day would not cause ill effects for most people, however people with high blood pressure or who are pregnant need to limit their caffeine intake.

A smaller daily dose of caffeine has not been tested to see if it would produce the same beneficial effects on the Alzheimer's mice.

However in the most recent experiments, the researchers also found that caffeine did not improve the memory of normal mice as it did for the Alzheimer's mice.

"This suggests that caffeine will not increase memory performance above normal levels. Rather, it appears to benefit those destined to develop Alzheimer's disease," Arendash said.

In a news release Huntington Potter, director of the Florida Alzheimer's Disease Research Center, said studies were needed to test whether caffeine could help people with mild cognitive impairment or early Alzheimer's disease.