Coffee may jolt more than just the nervous system.
A new French study found that caffeine seemed
to help preserve the cognitive skills of older
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
disease but which also occurs in normal
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.
Ritchie and her colleagues recruited more than
7,000 women and men from three French cities.
All were dementia-free at the start of the study.
The researchers evaluated cognitive performance
with a series of tests, such as verbal recall,
asking people to demonstrate how many words they
could repeat back after hearing them in 30 seconds.
The evaluations were done at the start of the
study and then two and four years later.
The researchers also asked about caffeine consumption
at each evaluation.
Ritchie's team did not find that caffeine
reduced the rate of dementia that developed within
the four-year follow-up period. But the follow-up
may not have been long enough to determine for
sure if caffeine protected not just thinking skills
but helped to ward off dementia. More research
is needed to find out if caffeine may actually
prolong the period of mild cognitive impairment
in women before they receive a diagnosis of dementia,
The study results are published in the Aug. 7
issue of the journal Neurology.
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
The Ritchie research "is another piece of
the puzzle," Scott said. "The next step
is to figure out what that mechanism is."
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.
Meanwhile, Scott concluded: "What I would
say to people over 65 is that there seems to be
a consistent, inverse association between caffeine
consumption and some of these neurodegenerative
diseases." Unless a physician advised against
it, he added, daily coffee drinking "doesn't
seem to hurt."