Caffeine Protects Blood-Brain Barrier, May Prevent Alzheimer’s Disease

A cup of coffeeScientists at the University of North Dakota have found that as little as one cup of coffee a day might be enough to protect the brain from Alzheimer’s disease by strengthening the blood-brain barrier (BBB).

In the study, published in the Journal of Neuroinflammation, researchers used New Zealand white rabbits to examine the effects of a high cholesterol diet and/or high levels of caffeine consumption on the blood-brain barrier. The blood brain barrier protects the brain from chemicals circulating in the blood that can disrupt brain function. Leakages of the blood-brain barrier are believed to occur in neurological disorders such as Alzheimer’s disease, Parkinson’s disease, and strokes.

In Alzheimer’s disease it is believed that leakages in the blood-brain barrier allow blood containing amyloid beta protein to cross into the brain. Deposits of amyloid beta plaques are found in the brains of Alzheimer’s sufferers and are associated with brain cell toxicity and death. High levels of dietary cholesterol are linked with increased linkages of the blood-brain barrier so it is hypothesized that high cholesterol diets may increase the risk of Alzheimer’s disease.

The 24 rabbits used in the study were divided into four groups. One group received a normal diet, the second group received a normal diet supplemented with 3mg a day of caffeine added to the rabbits drinking water, a third group received a high cholesterol diet, and the final group received both a high cholesterol diet and 3mg of caffeine daily. The diets were administered for the full 12 week duration of the study.

The researchers found that the high cholesterol diets increased the levels of fibrinogen and IgC in the rabbits’ brains. These two substances are usually blocked from entering the brain by the blood brain barrier so high levels of the chemicals indicates leakages in the blood brain barrier. The rabbits who received both the high cholesterol diets and the caffeine had normal levels of fibrinogen and IgC indicating that caffeine prevented the breakdown of the blood-brain barrier caused by the high cholesterol diet.

The authors of the study concluded that: “chronic ingestion of caffeine protects against high cholesterol diet-induced disruption of the blood-brain barrier”.

The 3mg of caffeine a day administered to the rabbits is equivalent to around 50mg of caffeine a day in humans. This is equivalent to just one cup of coffee, one can of coke, two cups of black tea, or 80g (2.8oz) of dark chocolate a day.