Aug. 6, 2007 -- The caffeine in three daily cups of coffee or tea may help older women preserve their memory, a new French study shows.
Researchers included Karen Ritchie, PhD, of the French National Institute for Health and Medical Research (INSERM) in Montpellier, France.
Ritchie's team studied some 7,000 men and women aged 65 and older (average age: 74) in three French cities: Bordeaux, Dijon, and Montpellier.
When the study started, participants reported how many daily cups of tea and coffee they drank. They also noted all of their medications, since some drugs contain caffeine. Few drank colas or cocoa, which also contain caffeine.
Participants took several tests of their mental skills, including a memory test based on a list of words. They repeated those tests two years later and again four years after the study began.
Women who reported drinking at least three cups of coffee or tea per day at the study's start showed less of a drop in their test scores during the study, compared with women who reported consuming at most one daily cup of tea or coffee.
The biggest benefit was seen in the women's verbal memory.
It didn't matter if the women favored coffee or tea. That finding suggests that the caffeine was what mattered most, according to the researchers.
But caffeine didn't seem to affect women's risk of developing dementia, including Alzheimer's disease. The study may have been too short to show such a benefit, the researchers note.
What about men? The data show no caffeine benefits in men's test scores over the years. Women may be more sensitive to caffeine's effects, according to Ritchie and colleagues.
Caffeine consumption may merely be a marker of other health habits that affect memory. Ritchie's team considered that possibility. The study's results didn't change.
Still, observational studies such as this one don't prove cause and effect. That is, the researchers didn't directly test caffeine to see whether it helps save women's memory.