Once again, a recent study found that daily consumption of coffee has health benefits.
Recent research found that drinking a moderate amount of coffee (2 to 3 cups of daily) or 1 to 2 cups of tea daily was associated with a lower risk of dementia and better cognitive function. Decaf coffee appeared to have no effect on risk of dementia or cognitive functioning.
Persons with the highest intake (2 to 3 cups or more daily) of caffeinated coffee had an 18% lower risk of dementia compared with those who drank little or no caffeinated coffee. The large study followed people for as long as 43 years.
From Medical Xpress: Consuming 2–3 cups of coffee daily associated with lower dementia risk, better cognitive function
A new prospective cohort study by investigators from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard analyzed 131,821 participants from the Nurses' Health Study (NHS) and Health Professionals Follow-Up Study (HPFS), finding that moderate consumption of caffeinated coffee (two to three cups a day) or tea (one to two cups a day) reduced dementia risk, slowed cognitive decline, and preserved cognitive function.
Their results are published in JAMA.
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.
Though promising, findings about the relationship between coffee and dementia have been inconsistent, as studies have had limited follow-up and insufficient detail to capture long-term intake patterns, differences by beverage type, or the full continuum of outcomes—from early subjective cognitive decline to clinically diagnosed dementia.
Data from the NHS and HPFS help to overcome these challenges. Participants 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 more than 130,000 participants, 11,033 developed dementia. Both male and female participants with the highest intake of caffeinated coffee had an 18% lower risk of dementia compared with those who reported little or no caffeinated coffee consumption.
Caffeinated coffee drinkers also had a lower prevalence of subjective cognitive decline (7.8% versus 9.5%). By some measurements, those who drank caffeinated coffee also showed better performance on objective tests of overall cognitive function.
Higher tea intake showed similar results, while decaffeinated coffee did not—suggesting that caffeine may be the active factor producing these neuroprotective results, though further research is needed to validate the responsible factors and mechanisms.
The cognitive benefits were most pronounced in participants who consumed two to three cups of caffeinated coffee or one to two cups of tea daily. Contrary to several previous studies, higher caffeine intake did not yield negative effects—instead, it provided similar neuroprotective benefits to the optimal dosage.
"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, MBBS, MS, Ph.D. student at Harvard Chan School and a research trainee at Mass General Brigham.