A new study has uncovered a surprising link between daily tea and coffee consumption and cognitive performance in older adults, suggesting that moderate intake of these beverages may help protect memory and reasoning skills as people age.
Published in the Journal of Alzheimer’s Disease, the study followed more than 8,700 adults in the UK, aged 60 to 85, over a period of nearly 10 years. Participants were assessed for changes in their cognitive abilities through a series of computer-based tests that measured reaction times, problem-solving, memory, and visual recognition.
The researchers found that those who consumed one to three cups of coffee or tea per day experienced a slower rate of cognitive decline than non-drinkers or heavy coffee consumers. Specifically, moderate drinkers performed better in memory and problem-solving tasks compared to those who abstained from caffeine altogether.
However, the study also revealed a downside to excessive coffee consumption. Participants who drank four or more cups of coffee a day showed faster cognitive decline, making more errors in visual memory tasks over time, as reported by News Medical.
“Those who abstained from coffee or had a moderate intake exhibited a slower cognitive decline over time,” the researchers noted. “Participants consuming four or more cups of coffee daily made more errors in pair matching as years passed, indicating a faster cognitive decline.”
Interestingly, tea drinkers showed a different trend. While they initially scored lower on cognitive tests at the start of the study, their rate of decline was slower over time—especially among those who consumed moderate to high amounts of tea daily.
“Moderate to high tea drinkers demonstrated less cognitive decline compared to non-tea drinkers,” the study stated. However, tea intake was not significantly associated with improvements in reaction times, numerical memory, or pair-matching accuracy.
Researchers suspect that caffeine content may be a key factor. A typical cup of tea contains about 28 to 45 milligrams of caffeine, while a cup of coffee contains roughly 95 milligrams. The difference may help explain why excessive coffee intake could have adverse cognitive effects, while tea may offer more stable benefits.
Still, the underlying mechanisms remain unclear. The study did not investigate how different types of tea or coffee, brewing methods, or added ingredients like milk and sugar might influence results.
Previous research, including a 2022 Chinese study, has also shown that high tea consumption is linked to lower rates of cognitive decline, reinforcing the potential protective benefits of the beverage in aging populations.
Further studies are needed to determine how preparation methods and other lifestyle factors may interact with caffeine intake and brain health.