Coffee and tea, possible allies of the brain

Regular consumption of coffee or caffeinated tea could contribute, to a certain extent, to maintaining brain health and reducing the risk of dementia, according to a large study conducted in the United States and recently published. Although the results are considered promising, researchers emphasize that they should be interpreted with caution and do not replace established prevention strategies.

• A study conducted over four decades

The research, published in the prestigious journal JAMA, was based on data provided by approximately 132,000 American adults, followed over almost 40 years. Participants periodically completed questionnaires on their consumption habits, including the amount of coffee and tea ingested daily. The analysis showed that people with the highest consumption of caffeinated coffee had an 18% lower risk of developing dementia, compared with those who reported minimal or no consumption.

• Less memory problems in coffee drinkers

In addition to the reduced risk of dementia, the researchers also found an association between coffee consumption and a lower rate of self-perceived memory or thinking problems. The difference was almost two percentage points between people with the highest and lowest coffee consumption. Similar results were seen with caffeinated tea, while decaffeinated drinks were not associated with comparable benefits, the study authors said.

• Caffeine is not a "miracle cure”

However, the researchers caution that the study does not demonstrate a direct causal relationship. "While the results are encouraging, they do not prove that caffeine is directly responsible for protecting the brain,” the authors stressed. The study's lead author, Dr. Daniel Wang, of Harvard Medical School, said the effect was relatively modest and that there are other, better-documented ways to maintain cognitive function as we age. These include regular physical activity, a balanced diet, and adequate sleep.

• The optimal amount: not too much, not too little

The greatest benefits were seen in participants who consumed two to three cups of caffeinated coffee or one to two cups of caffeinated tea daily. In addition, caffeinated coffee drinkers performed better on some objective tests of cognitive function.

The study, funded by the National Institutes of Health (NIH), suggests that bioactive ingredients in coffee and tea - such as caffeine and polyphenols - could reduce inflammation and damage to nerve cells, thereby helping to protect the brain.

Another important aspect of the research is the analysis of genetic predisposition. According to Dr. Yu Zhang, co-author of the study and a researcher at Harvard T.H. Chan School of Public Health, the positive effects were similar among people with a high genetic risk of dementia and those with a low risk. "This suggests that coffee or caffeine may be equally beneficial for both groups,” the researcher explained. However, the authors emphasize the need for further studies to identify the exact mechanisms underlying these associations.