Coffee drinking linked to slower brain ageing

"The study offers what the authors think is the longest-term data to date on the relationship between caffeine consumption and cognition. It found that moderate caffeine intake from coffee and tea was associated with reductions in both dementia risk and the rate of cognitive decline. Specialists praise the study for its size but note that the results should be interpreted with caution."

"Many studies have investigated the link between caffeine and cognition. But Yu Zhang, an epidemiologist at Harvard University in Cambridge, Massachusetts, and first author of the study, says that previous work followed participants over relatively short periods, whereas dementia builds over many decades. For its work, Zhang's group leveraged two decades-long health studies - the Nurses' Health Study and the Health Professionals Follow-up Study - to track the caffeine-drinking habits of more than 130,000 health-care professionals over 43 years."

Two decades-long health cohorts tracked more than 130,000 health-care professionals for 43 years, with repeated diet questionnaires and cognitive assessments. Moderate caffeine intake—about 2–3 cups of coffee or 1–2 cups of tea per day—was associated with lower dementia risk and slower cognitive decline. Cognitive function was measured both by self-report questionnaires and objective memory tests requiring recall of word lists. Observational design limits causal inference, and specialists note that results are suggestive rather than definitive. The large sample size and long follow-up strengthen the association, but residual confounding and measurement limits remain important caveats.

Read at Nature