A large new study has found that drinking two to three cups of coffee a day or one to two cups of tea was associated with reduced dementia risk, slower cognitive decline, and better preserved brain function.
The research, published in JAMA, was led by scientists from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard, and analyzed data from 131,821 participants tracked for decades.
Investigators examined repeated dietary surveys alongside reports of dementia, subjective cognitive decline, and performance on cognitive tests, with follow-up periods stretching as long as 43 years. They then compared outcomes among people who consumed caffeinated coffee, tea, or decaffeinated coffee.
“When searching for possible dementia prevention tools, we thought something as prevalent as coffee may be a promising dietary intervention — and our unique access to high quality data through studies that have been going on for more than 40 years allowed us to follow through on that idea,” said senior author Daniel Wang, an associate scientist at Mass General Brigham and assistant professor at Harvard Medical School.
“While our results are encouraging, it’s important to remember that the effect size is small and there are lots of important ways to protect cognitive function as we age. Our study suggests that caffeinated coffee or tea consumption can be one piece of that puzzle.”
Researchers followed more than 130,000 adults for up to 43 years
Out of the full group, 11,033 participants developed dementia during the study period. Those with the highest caffeinated coffee intake had an 18 percent lower risk of dementia compared with people who reported little or no caffeinated coffee consumption. Caffeinated coffee drinkers also showed lower rates of subjective cognitive decline, at 7.8 percent versus 9.5 percent.
By some measures, coffee drinkers also performed better on objective tests of overall cognitive function. Higher tea intake produced similar patterns, while decaffeinated coffee did not.
Researchers said these points point to caffeine as a possible factor behind the effect, though they noted that additional work is required to confirm the biological mechanisms involved.
The strongest associations appeared in participants who drank two to three cups of caffeinated coffee or one to two cups of tea per day. Unlike several earlier reports, higher caffeine intake did not show negative cognitive effects in this analysis.
“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 research trainee at Mass General Brigham.
The authors added that dementia prevention remains a major focus for researchers because existing treatments are limited once symptoms appear, driving continued investigation into lifestyle factors such as diet and long-term beverage consumption.
If you’re not a fan of the fancy bean water, you can also just eat certain types of cheese to fight off dementia, and ward off alzheimers by smelling your own farts. If you add extra cheese to your diet, though, don’t be surprised if you start to have nightmares.
