A recent study has found that drinking two to three cups of caffeinated coffee or one to two cups of tea daily is associated with a lower risk of dementia...READ FULL; FROM THE SOURCE.
The study, published on Monday in the Journal of the American Medical Association, analysed the health records and caffeine consumption habits of health professionals using two long-running research datasets spanning 1980 to 2023.
The first dataset included more than 86,000 women, with an average age of 46, from the Nurses’ Health Study, while the second involved over 45,000 men, with an average age of 54, from the Health Professionals Follow-Up Study, which focuses on men’s health.
Participants completed dietary questionnaires every two to four years to track their intake of regular coffee, decaffeinated coffee, and tea.
After a median follow-up period of nearly 37 years, more than 11,000 participants had been diagnosed with dementia.
The study found that higher consumption of caffeinated coffee or tea was linked to a reduced risk of developing dementia, with the association being stronger among individuals aged 75 and younger.
It showed that people who consumed the highest amounts of caffeinated coffee had an 18 per cent lower risk of dementia compared with those who consumed the least. Similarly, among tea drinkers, those with the highest intake recorded a 14 per cent lower risk than those with the lowest consumption.
The researchers also identified the optimal intake for each beverage. Compared with people who did not consume coffee or tea, those who drank two to three cups of caffeinated coffee or one to two cups of tea daily had the lowest risk of dementia. This level of intake corresponds to roughly 300 milligrams of caffeine per day.
The study also assessed participants’ subjective cognitive decline and objective cognitive function, referring to individuals’ perception that their memory and thinking abilities were worsening, which is often an early indicator of dementia.
At various points during the follow-up period, participants completed questionnaires designed to evaluate memory, attention, executive function and visuospatial skills. In addition, women aged 70 and older underwent telephone-based cognitive assessments, including the East Boston Memory Test, while older men were not tested using this method.
The findings showed that participants who consumed more caffeine recorded slightly better cognitive scores for their age, suggesting that their cognitive decline was slower by an estimated seven months.
The authors noted that caffeine may help protect brain health due to compounds that reduce neuroinflammation or support vascular function.
Several studies have also suggested that caffeine improves insulin sensitivity, which may lower the risk of diabetes, a known risk factor for dementia.
Commenting on the findings, Aladdin Shadyab, an associate professor of public health and medicine at the University of California, said the results do not mean people who avoid caffeine should be encouraged to start drinking coffee.
However, he added that the study is reassuring for current coffee drinkers, as it suggests a possible reduced risk of dementia.
Similarly, Fang Fang Zhang, an epidemiologist at Tufts University’s Friedman School of Nutrition Science and Policy, said non-caffeine drinkers could consider trying small amounts, particularly if they are sensitive to caffeine.
However, the study has several limitations. As an observational study, it was only able to identify associations and could not establish a direct cause-and-effect relationship between caffeine intake and healthier cognitive ageing.
The research also did not distinguish between regular and decaffeinated tea, nor did it specify tea varieties such as black, green or white. Similarly, details on coffee preparation methods were not provided.
The authors noted that factors including roast level, bean origin and brewing techniques could influence caffeine content and the concentration of other bioactive compounds.
In addition, participants self-reported their caffeine intake from sources such as soda and chocolate, which are not typically considered healthy options.
The study also did not account for whether participants added milk, cream, sugar or other sweeteners to their beverages.
Meanwhile, another study discovered a link between sugar-sweetened beverages and increased risk of cognitive impairment.
