Researchers at the University of North Dakota School of Medicine and Health Sciences have determined the caffeine equivalent of just one cup of coffee a day could protect the blood-brain barrier from damage that occurred with a high-fat diet.

The researcher fed rabbits cholesterol-enriched diet and also gave them 3 milligrams of caffeine each day -- the equivalent of a daily cup of coffee for an average-size person.

The study, published in the Journal of Neuroinflammation, said that after 12 weeks a number of laboratory tests showed the blood-brain barrier was significantly more intact in rabbits receiving a daily dose of caffeine.

"Caffeine appears to block several of the disruptive effects of cholesterol that make the blood-brain barrier leaky," Jonathan Geiger said in a statement. "High levels of cholesterol are a risk factor for Alzheimer's disease, perhaps by compromising the protective nature of the blood-brain barrier."

Its the first time chronic ingestion of caffeine has been shown to protect the blood-brain barrier from cholesterol-induced leakage, Geiger said.