New Study Links 2-3 Cups Coffee to 18% Lower Dementia Risk

Drinking a few cups of caffeinated coffee or tea each day may significantly lower a person's risk of developing dementia. New long-term research found that adults who regularly consumed two to three cups of caffeinated coffee daily had an 18 percent lower risk of dementia. Those who drank one to two cups of caffeinated tea daily saw similar benefits.^{[emjreviews+8]}

The findings come from a large prospective study, which tracked more than 130,000 participants for up to 43 years.Researchers from Harvard University led the analysis, which was published in the Journal of the American Medical Association.^{[emjreviews+15]}

Decades of Data Show Clear Link

The study analyzed health and dietary information from two major U.S. health cohorts: the Nurses' Health Study and the Health Professionals Follow-up Study.These cohorts provided data from 131,821 individuals who were free of dementia, Parkinson's disease, and cancer when the study began.Researchers collected dietary intake information every two to four years using detailed questionnaires.^{[emjreviews+23]}

Over a median follow-up period of nearly 37 years, scientists documented 11,033 new cases of dementia.The analysis showed a significant association between higher caffeinated coffee intake and a lower risk of dementia.^{[emjreviews+8]}

Dr. Yu Zhang, a nutritional epidemiologist at Harvard University and lead author of the study, noted the strength of the evidence. "Our study alone can't prove causality, but to our knowledge, it is the best evidence to date looking at coffee and tea intake and cognitive health," Zhang told The Guardian.She added that the findings are consistent with plausible biological explanations.^{[theguardian+3]}

Caffeine Appears Key

The research found that the protective benefits were most pronounced with moderate intake levels. Specifically, two to three cups per day for caffeinated coffee and one to two cups per day for caffeinated tea showed the lowest dementia risk.Consuming more than these amounts did not lead to further reductions in risk, but also did not show negative effects on dementia risk in this study.^{[emjreviews+13]}

Importantly, the study found no significant link between decaffeinated coffee intake and a lower risk of dementia or better cognitive performance.This suggests that caffeine, or compounds closely related to it, may play a crucial role in the observed protective effects.Participants who drank caffeinated coffee also performed slightly better on objective cognitive tests and reported less subjective cognitive decline.^{[emjreviews+22]}

"Our results are reassuring that people with moderate coffee or tea intake tended to have more favorable cognitive outcomes over the long term," Zhang told Healio.^[healio]

How Coffee and Tea May Help the Brain

Scientists are exploring several ways coffee and tea might protect brain health. Both beverages contain caffeine and polyphenols, which are compounds known for their antioxidant and anti-inflammatory properties.Chronic inflammation and oxidative stress, where harmful molecules damage cells, are linked to brain aging and neurodegenerative diseases like dementia.^{[theguardian+15]}

Caffeine can block adenosine receptors in the brain, which increases alertness and reduces fatigue.It is also associated with improving vascular health and blood sugar control.Type 2 diabetes, for example, is a known risk factor for dementia.Other compounds in tea, like L-theanine, also contribute to brain health.^{[austinperlmutter+5]}

Dr. Susan Kohlhaas, Executive Director of Research at Alzheimer's Research UK, commented on the study's implications. "This long-running study suggests that people who regularly drank moderate amounts of coffee or tea were less likely to develop dementia later in life," she said.However, she also cautioned, "This research doesn't prove that coffee or tea protect the brain."^{[alzheimersresearchuk+4]}

Important Considerations and Future Research

While the findings are encouraging, experts emphasize that this observational study shows an association, not a direct cause-and-effect relationship.Other factors related to the lifestyle of coffee and tea drinkers could also play a role in their lower dementia risk.For instance, people with sleep problems, which can increase cognitive decline risk, might avoid caffeine.^{[emjreviews+14]}

Future research needs to confirm whether these beverages directly drive biological changes that protect the brain.This would involve studies exploring specific mechanisms and conducting randomized controlled trials, though long-term trials of this nature are challenging to implement.^{[emjreviews+10]}

For now, the data suggest that incorporating moderate amounts of caffeinated coffee or tea into a healthy lifestyle may be part of strategies for healthier cognitive aging.However, a balanced approach to brain health still includes physical exercise, a healthy diet, and adequate sleep.^{[emjreviews+4]}