A daily dose of caffeine blocks the disruptive effects of high cholesterol that scientists have linked to the disease, a study has found.

The findings, in the Journal of Neuroinflammation, were based on research by scientists at the University of North Dakota School of Medicine and Health Sciences.

In the study, researchers gave rabbits 3mg of caffeine each day, the equivalent of a daily cup of coffee for an average-sized person. The rabbits were fed a cholesterol-enriched diet during this time.

After 12 weeks, a number of laboratory tests showed that the blood brain barrier - which protects the central nervous system from the rest of the body's circulation - was "significantly" more intact in rabbits receiving a daily dose of caffeine.

Previous studies have shown that high levels of cholesterol break down the blood brain barrier which can then no longer protect the central nervous system from the damage caused by blood borne contamination. Leakage in the blood brain barrier occurs in a number of neurological disorders, such as Alzheimer's disease.

Jonathan Geiger, of the University of North Dakota School of Medicine and Health Sciences, said: "For the first time we have shown that chronic ingestion of caffeine protects the blood brain barrier from cholesterol-induced leakage."

He added: "Caffeine is a safe and readily available drug and its ability to stabilise the blood-brain barrier means it could have an important part to play in therapies against neurological disorders."

The research confirms earlier studies showing that caffeine intake protects against memory loss in ageing and in Alzheimer's disease.

There are estimated to be 700,000 people in the UK with dementia, with around two thirds of these suffering from Alzheimer's.