Coffee or tea intake may be linked to lower dementia risk

A Harvard and Mass General Brigham study of about 131,821 people followed for roughly 43 years found daily caffeinated coffee or tea drinkers had up to about a 20% lower risk of dementia, with the strongest association seen for two to three cups of coffee or one to two cups of tea.

Researchers from Harvard and Mass General Brigham report an association between daily caffeinated coffee or tea consumption and lower dementia risk. The team followed about 131,821 people for roughly 43 years and published their findings in JAMA. Study authors highlighted that two to three cups of coffee or one to two cups of tea per day showed the strongest association with reduced risk. Unaffiliated experts emphasized that the results show an association and do not prove cause and effect. Key findings: - The study followed approximately 131,821 participants over about 43 years; 11,033 participants developed dementia during follow-up. - Daily consumption of caffeinated coffee or tea was associated with up to about a 15–20% lower risk of dementia; the reported “sweet spot” was two to three cups of coffee or one to two cups of tea per day. - High consumers of coffee in the study still showed an estimated 18% lower risk compared with those who drank little or no coffee. - No association was observed for decaffeinated coffee, which led authors to suggest caffeine as a possible active factor; the study also notes that coffee and tea contain polyphenols and other compounds that may influence brain health. - The article cites Health Canada guidance that adults limit caffeine to 400 mg per day (about three cups of brewed coffee) and notes potential side effects such as insomnia, irritability, headaches and nervousness. Summary: The study adds to evidence that caffeinated coffee or tea consumption is associated with lower dementia risk, while stopping short of establishing causation. Undetermined at this time.