POSITIVE HEALTH EFFECTS

POSITIVE HEALTH EFFECTS

Although we always urge caution when interpreting correlational studies, a recent large study based at the National Cancer Institute collected health data from more than 400,000 individuals in their fifties and sixties start¬ing in 1995 and following them for thirteen years. Across that time, men who drank two or three cups of coffee per day were 10 percent less likely to have died, and women were 13 percent less likely to have died. The study was not designed to answer the question of why coffee drinking was associated with better survival, but the findings are worth knowing about.

Two studies published in 2012 suggest that caffeine may also have bene¬fits for memory function when memory is challenged or in decline. In one study, individuals with "mild cognitive impairment"—a strong predictor of Alzheimer's disease—had their memory function evaluated and caf¬feine levels measured at the beginning of the study and again several years later. Those who had caffeine levels consistent with drinking about three cups of coffee were significantly less likely to have developed Alzheimer's disease than were those with no caffeine in their systems. This doesn't mean that caffeine prevents Alzheimer's disease. It could be that there was something else about the lifestyles of the people who had caffeine in their systems that helped forestall the onset of full Alzheimer's symptoms. For example, because caffeine in a stimulant it could simply have made the subjects more alert, making them more likely to engage in social or intellectual activities, both of which have been shown to promote cogni¬tive health in older people. The second recent study was a lab experiment with animals that had their memory function impaired when their brains were deprived of oxy­gen for a brief time. This condition, called "ischemia," often happens when people suffer a stroke and is known to result in memory and other cognitive deficits. Half of the mice received a dose of caffeine before the oxygen deprivation and the other half did not. Later, the mice that had received the caffeine regained their ability to form new memories 33 per­cent faster than the ones that had received no caffeine. It was as if the presence of caffeine at the time of the ischemia protected the animals' brains from suffering the full effect of the loss of oxygen. This could have been due to the caffeine disrupting the actions of adenosine in the brain. We wrote about how this action is part of why caffeine creates alertness. But when brain cells are injured or under stress, adenosine can reach dan­gerously high levels and actually damage the cells. Having the caffeine on board when the animals brains were stressed may have reduced the potential toxic effect of adenosine. Of course, this does not mean that everybody should walk around buzzed on caffeine all the time just in case they suffer a stroke or brain injury. But if it happens to be there, it might be protective.