According to a new peer-reviewed study, women who drink two to three cups of coffee a day may have better brain functioning in later life. (Sorry dudes, this benefit doesn’t appear to apply to you.)
For the study, researchers from University of Wisconsin-Milwaukee looked into the benefits of caffeine consumption on brain function in postmenopausal women. Specifically, they wanted to find out whether almighty caffeine could delay or help prevent dementia and cognitive decline over 10 years. They were inspired by previous research suggesting caffeine may have some protective affects against cognitive impairment and Alzheimer’s Disease, which is the most common cause of dementia.
For the study, the researchers recruited 6,467 women from the Women’s Health Initiative Memory Study (WHIMS), an ongoing randomized controlled clinical trial testing postmenopausal hormone therapy. (Because participants were randomly selected, some were on hormone-therapy and some were on placebos, but researchers adjusted for this.) Recruitment occurred from 1995 to 1999.
Every year from recruitment through 2007, each participant’s cognitive function was assessed. Meanwhile, caffeine intake was measured at the start of the study then two additional times, through self-reported questionnaires, which included questions about frequency and serving size of coffee, tea, and other caffeinated beverages.
By the end of the study, 209 women received a classification of probable dementia (PD) and 388 received a classification of composite cognitive impairment. However, women who consumed more coffee were less likely to end up in the probable dementia or cognitive impairment group. Specifically, according to the study, above-median baseline caffeine intake (around two to three cups of coffee a day) was associated with lower incidence of both probable dementia and cognitive impairment. In other words, the women who, at the start of the study, averaged higher caffeine intakes—in this case two to three cups a day—fared better than women who consumed below median amounts.
Of course, this is not to say drinking coffee will absolutely prevent dementia. The effect found by the researchers was minimal; when breaking down the results, higher self-reported caffeine intake was associated with only a 26% reduction in risk of dementia. Not to mention the study showed correlation but not causation. According to the authors, however, their findings are relevant because they echo previous research. “Our findings suggesting lower risk of PD [probable dementia] incidence in women with higher caffeine consumption are generally consistent with the literature,” they write.
In a previous study published in the journal Neurology found that the psychostimulant properties of caffeine appear to reduce cognitive decline in women over 65. In that study, women who drank three or more cups of coffee a day showed less cognitive decline over four years than women who drank one cup or less. No relation was found between caffeine intake and cognitive decline in men. (The authors of the new study did not include male participants, but generally, past research has been mixed on whether caffeine has the same protective effects for men.)
Notably, Alzheimer’s and dementia affect women at a greater rate than men. By the age of 65, women have a 1 in 6 chance of developing Alzheimer’s, compared to a 1 in 11 chance for men. Which is why caffeine’s protective powers, if they are proven legitimate in future research, could be helpful to millions of women.
“The mounting evidence of caffeine consumption as a potentially protective factor against cognitive impairment is exciting given that caffeine is also an easily modifiable dietary factor with very few contraindications,” explained Ira Driscoll, Ph.D., the study’s lead author and a professor of psychology at the University of Wisconsin-Milwaukee.