Caffeine to Fight Alzheimer’s?

Portuguese researchers have assembled a collection of 22 scientific papers that deal with the ability of caffeine to protect against the detriment brain effects of Alzheimer’s and other dementias.  The papers were originally given as presentations in a meeting on Caffeine and the brain in Lisbon on in 2009.  They are now published in the Journal of Alzheimer’s Disease.

During recent years epidemiological studies have shown that the consumption of moderate amounts of caffeine is associated with a reduced risk of age-related cognitive decline and Alzheimer’s disease.  And lab studies have shown that chronic caffeine administration prevents memory deterioration and brain nerve cell degeneration in animal models of aging and Alzheimer’s disease.

Unfortunately, many of the papers deal with pharmacological studies of caffeine in animals, helping to delineate the different effects the substance has – chiefly as an antagonist of different subtypes of adenosine receptors, but also as an inhibitor of phosphodiesterases, the promotion of calcium release from intracellular stores, and interference with GABA receptors.

One paper, from INSERM France, reviews what is known of the prevention of cognitive decline in healthy subjects.   The results of the studies are quite variable, some finding no age-related effect while others report effects only in one sex and mainly in the oldest population. The reviewer concludes that caffeine cannot be considered a `pure' cognitive enhancer. Its indirect actions on arousal, mood and concentration are most probably responsible for its perceived cognitive enhancing properties.

The concentration on lab work is disappointing.  There are many frustrations in extrapolating findings from animal studies to humans.  However, such work is necessary to be able to tease out the actual mechanism by which one or other actions of caffeine may be useful in a treatment for dementia.  For the time being, I’m just sticking with coffee - 4 to 5 cups a day.