For thousands of years,coffee has been one of the two or three most popular beverages on earth. But its only recently that scientists are figuring out that the drink has notable health benefits. In one large-scale epidemiological study from last year,researchers primarily at the National Cancer Institute parsed health information from more than 4,00,000 volunteers,ages 50 to 71,who were free of major diseases at the studys start in 1995. By 2008,more than 50,000 of the participants had died. But men who reported drinking two or three cups of coffee a day were 10 per cent less likely to have died than those who didnt drink coffee,while women drinking the same amount had 13 per cent less risk of dying during the study. Its not clear exactly what coffee had to do with their longevity,but the correlation is striking.
Other recent studies have linked moderate coffee drinking the equivalent of three or four 150 ml cups of coffee a day or a single venti-size Starbucks with more specific advantages: a reduction in the risk of developing Type 2 diabetes,basal cell carcinoma (the most common skin cancer),prostate cancer,oral cancer and breast cancer recurrence.
Perhaps most consequential,animal experiments show that caffeine may reshape the biochemical environment inside our brains in ways that could stave off dementia. In a 2012 experiment at the University of Illinois at Urbana-Champaign,mice were briefly starved of oxygen,causing them to lose the ability to form memories. Half of the mice received a dose of caffeine that was the equivalent of several cups of coffee. After they were re-oxygenated,the caffeinated mice regained their ability to form new memories 33 per cent faster than the uncaffeinated. Close examination of the animals brain tissue showed that the caffeine disrupted the action of adenosine,a substance inside cells that usually provides energy,but can become destructive if it leaks out when the cells are injured or under stress. The escaped adenosine can jump-start a biochemical cascade leading to inflammation,which can disrupt the function of neurons,and potentially contribute to neurodegeneration or,in other words,dementia.
In a 2012 study of humans,researchers from the University of South Florida and the University of Miami tested the blood levels of caffeine in older adults with mild cognitive impairment,or the first glimmer of serious forgetfulness,a common precursor of Alzheimers disease,and then re-evaluated them two to four years later. Participants with little or no caffeine circulating in their bloodstreams were far more likely to have progressed to full-blown Alzheimers than those whose blood indicated theyd had about three cups worth of caffeine.