Study Finds Caffeine Intake Linked to Lower Dementia Risk

A large analysis of two long-term U.S. cohorts found that moderate caffeinated coffee (one to five eight-ounce cups daily) was associated with about an 18% lower dementia risk and caffeinated tea with roughly 15% lower risk; researchers said causation cannot be confirmed.

Researchers reported results from a large, long-term analysis linking caffeine intake and measures of cognitive health. The analysis used participants from the Nurses' Health Study and the Health Professionals Follow-Up Study, with starting ages typically in the mid-40s to early 50s. Investigators compared self-reported caffeinated coffee and tea consumption with later measures of dementia and subjective cognitive decline. The report notes associations and includes cautions that causation cannot be established. Key findings: - Drinking between one and five eight-ounce cups of caffeinated coffee daily was associated with about an 18% lower risk of developing dementia. - Daily caffeinated tea was associated with roughly a 15% lower risk of dementia. - Reported benefits plateaued beyond about 2.5 cups of coffee per day. - Those who reported higher caffeine intake were less likely to report subjective cognitive decline; among women over 70, higher intake corresponded to cognitive test results suggesting about seven months slower decline. - Authors noted possible biological mechanisms, including caffeine blocking adenosine receptors, increased neuron activity, rises in dopamine and acetylcholine, and potential reductions in oxidative stress and neuroinflammation. - Researchers cautioned they could not prove causation, pointed to possible confounding (for example, some participants may have consumed decaffeinated coffee for health reasons), and noted concerns mentioned in the report about dehydration from coffee's diuretic effects and sleep disruption in older adults. Summary: The study reports an association between moderate caffeinated beverage consumption and lower reported dementia risk and related cognitive measures in these cohorts. Undetermined at this time.