The caffeine in three cups of coffee or tea a day may help maintain mental sharpness in older women, but caffeine consumption appears to have no effect in men.
French researchers studied more than 7,000 men and women with an average age of 74, following them over four years. They determined coffee and tea intake by interview, and they measured mental acuity with widely accepted tests of visual skills and verbal recall. They also recorded information on education, income, depression, and alcohol and tobacco use, among other factors. The study appears in the August issue of Neurology.
After controlling for other variables, the scientists found that women at age 65 who drank three or more cups of coffee or tea a day were about one-third less likely to have a significant decline in verbal skills than those who drank a cup or less. By age 85, they were 70 percent less likely to suffer those deficits compared with women who drank less than a cup of coffee or tea. There were not enough cases to detect an effect on Alzheimer's disease. Karen Ritchie, the lead author and a research director with the French National Institute for Health and Medical Research, said it was unclear why caffeine had no effect in men. "It may be that men and women metabolise caffeine differently or that there is a hormonal interaction. "In any case," she continued, "please don't rush out and start drinking coffee. To suddenly start drinking large quantities of coffee is still really premature as a preventive measure."