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Women who drank three or more cups of coffee a day were 30 percent less likely to have memory decline at age 65 than whose who drank one cup or less daily. And the benefit increased with age. Women over age 80 who drank three or more cups of coffee a day were about 70 percent less likely to have memory decline than those who drank one cup or less. the researchers said.
Caffeinated tea had the same effect in the women. the study found, although more was needed to get the same caffeine boost. "Count roughly two cups of tea for a cup of coffee," said study leader Karen Ritchie of INSERM, the French National Institute for Health and Medical Research.
But the researchers didn't find a similarly protective effect in men, although other studies have found a benefit to males.
How might caffeine help ward off cognitive decline? "It is a cognitive stimulant." said Ritchie. It also helps to reduce levels of the protein called beta amyloid in the brain. she said. "whose accumulation is responsible for Alzheimer's disease but which also occurs in normal aging."
Ritchie said she wasn't sure why men in the study didn't benefit from caffeine. "Our hypothesis is that either women metabolize caffeine differently than men, or there may be an interaction of the caffeine with the sex hormones.the estrogen-progesterone balance," she said.
The French study confirms previous research, said William Scott. professor of medicine at the University of Miami Miller School of Medicine. who has researched caffeine's beneficial effects against Parkinson's disease, also a neurodegenerative disorder.
As for caffeine only protecting women, Scott noted that just 2,800 of the 7,000 study participants were men. and the results might have differed if more men were included.
A study published in February in the European Journal of Clinical Nutrition looked at 676 healthy men and found that regular coffee drinkers had a lower rate of cognitive decline over a 10-year follow-up than those who didn't drink coffee. Those who drank three cups daily had the least signs of decline.
Both Scott and Ritchie agreed that more study is needed. Ritchie's research will next look at the relationship between caffeine and Alzheimer's.
