Washington DC (US), May 17, 2026, BNN Web Staff: A major long-term study conducted in the United States has found that drinking moderate amounts of caffeinated coffee or tea every day may help reduce the risk of dementia, particularly in adults below the age of 75.
Researchers observed that people who consumed around 250mg to 300mg of caffeine daily — roughly equal to two to three cups of coffee — had a significantly lower risk of developing dementia compared to those who consumed little or no caffeine. The study linked moderate caffeine intake with nearly a 35 per cent reduction in dementia risk among adults aged 75 and younger.
The research tracked more than 1.3 lakh nurses and healthcare professionals over a period of up to 43 years, beginning when participants were in their early forties. During the study, over 11,000 participants developed dementia.
Scientists said caffeine may support brain health in several ways. It is believed to help keep important brain chemicals such as dopamine and acetylcholine active while also reducing inflammation and limiting the buildup of harmful amyloid plaques associated with Alzheimer’s disease.
The study also found that tea consumption showed promising benefits. Drinking one to two cups of tea daily was associated with lower dementia risk, although researchers noted that tea consumption in the US is generally lower than coffee consumption.
Experts cautioned, however, that consuming excessive amounts of caffeine did not provide additional benefits. Higher caffeine intake may interfere with sleep and increase anxiety, both of which can negatively affect brain health.
Researchers explained that the relationship between caffeine and mental performance may follow the “Yerkes-Dodson law,” a psychological principle suggesting that moderate stimulation improves performance, but excessive stimulation can have the opposite effect.
Interestingly, the study also observed that participants who consumed larger amounts of decaffeinated coffee showed faster memory decline. Researchers believe this could be because many people switch to decaf after developing conditions such as sleep problems, heart issues or high blood pressure, which themselves are linked to cognitive decline.
According to scientists, coffee and tea contain several compounds beyond caffeine, including antioxidants and nutrients that may help protect blood vessels and support healthy brain function as people age.
While the findings suggest that moderate caffeine intake could play a role in supporting cognitive health, researchers stressed that overall lifestyle factors such as balanced diet, physical activity, proper sleep and cardiovascular health remain equally important in lowering dementia risk.
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