Daily Coffee Habit May Cut Dementia Risk by Half, Harvard Study Finds

A new study suggests that drinking two to three cups of caffeinated coffee or tea daily could reduce dementia risk by more than half, as South Korea's dementia patient population is projected to exceed one million next year.

A research team led by Professor Daniel Wang at Harvard Medical School recently published these findings in JAMA (Journal of the American Medical Association).

The researchers tracked 131,821 participants over 43 years from 1980 to 2023, including 86,606 women from the Nurses' Health Study and 45,215 men from the Health Professionals Follow-up Study. During the observation period, 11,033 cases of dementia were recorded.

The analysis revealed that the group consuming the most caffeinated coffee (top 25%) had 141 dementia cases per 100,000 people, less than half the 330 cases in the lowest consumption group (bottom 25%). Specifically, those drinking two to three cups of caffeinated coffee daily showed an 18% lower dementia risk, while those consuming one to two cups of tea daily had a 15% reduced risk.

Higher coffee consumption was associated with less subjective memory decline and better cognitive test scores. Decaffeinated coffee showed no such benefits, identifying caffeine itself as the key component for brain health protection.

"A food as widely consumed in daily life as coffee could be one piece of the puzzle for cognitive protection," Professor Wang said. However, the research team noted that as an observational study, the influence of other lifestyle factors cannot be ruled out.

The findings are expected to draw attention in South Korea. According to the Ministry of Health and Welfare, the country currently has 970,000 dementia patients, projected to surpass one million by 2026 and two million by 2044. With South Korea entering a super-aged society in December last year when the population aged 65 and older exceeded 20%, the importance of dementia prevention through dietary habits is growing.