Drinking two to three cups of strong coffee a day can reduce the risk of dementia and slow cognitive decline, a study has found.
Using data from over 130,000 patients from the Nurses' Health Study and Health Professionals Follow-Up Study, which covered a 40-year period, experts from Harvard, MIT and Mass General Brigham in the US, found that those with the highest intake of caffeinated drinks had an 18% lower risk of dementia.
This was compared with those who reported little or no caffeine consumption.
Higher tea intake (one or two cups daily) showed similar results, while decaffeinated coffee did not.
Consultant Endocrinologist Professor Donal O'Shea described the study as positive and "reassuring" for those worried about developing dementia.
Speaking on RTÉ’s Morning Ireland, he said the study showed a definite trend and reduction in the incidence of dementia, but he also recommended moderation.
"Two to three cups of coffee a day seems to be the sweet spot. Caffeine does affect your circulation, and the study was done on a relatively young population.
"The message is moderation, as too much of a good thing is never a good thing".
Coffee and tea contain bioactive ingredients like polyphenols and caffeine, which have emerged as possible neuroprotective factors that reduce inflammation and cellular damage while protecting against cognitive decline.
Participants in the study repeated assessments of diet, dementia, subjective cognitive decline, and objective cognitive function, and were followed for up to 43 years.
Researchers compared how caffeinated coffee, tea, and decaffeinated coffee influenced dementia risk and cognitive health of each participant.
Of the 131,821 participants, 11,033 developed dementia.
"We also compared people with different genetic predispositions to developing dementia and saw the same results - meaning coffee or caffeine is likely equally beneficial for people with high and low genetic risk of developing dementia," said lead author Yu Zhang, a student at Harvard Chan School and a research trainee at Mass General Brigham.
