Research suggests that tea and coffee may help reduce the risk of dementia.

According to the study, people who maintain a habit of drinking two to three cups of caffeinated coffee or one to two cups of caffeinated tea each day have a 15-20% lower risk of dementia compared to those who do not consume these beverages, while also exhibiting slightly better cognitive abilities.

The risk of developing dementia is 18% lower.

The analysis is based on the health records of more than 130,000 people over a follow-up period of more than 40 years.

The results showed that those who regularly consumed caffeinated coffee also reported less cognitive decline compared to the decaffeinated coffee group, and scored higher on several objective tests of brain function.

The study, published in the Journal of the American Medical Association, is the most comprehensive evidence to date on the link between tea and coffee consumption and cognitive health, and is consistent with plausible biological mechanisms.

According to the research team, coffee and tea contain caffeine and polyphenol compounds that may help protect the brain from aging by improving vascular health, reducing inflammation, and limiting oxidative stress—a condition in which free radicals damage cells and tissues.

Additionally, caffeine has been shown to be associated with a lower risk of type 2 diabetes, which is a known risk factor for dementia.

Data was collected from 131,821 volunteers participating in two large-scale studies in the US: the Nurses' Health Study and the Health Professionals Follow-up Study.

These studies conducted periodic assessments of diet, dementia diagnosis, cognitive decline, and brain function test results over up to 43 years.

The results showed that both men and women who drank a lot of caffeinated coffee had an 18% lower risk of dementia compared to the group who drank little or no coffee; a similar trend was observed for tea.

The effect appears to stabilize at a level of 2 to 3 cups of coffee or 1 to 2 cups of tea per day. No significant association was observed between decaffeinated coffee and the risk of dementia.

Expert advice

Experts believe more research is needed to determine whether tea and coffee actually offer any protective effects on the brain.

Cardiologists say that drawing a definitive conclusion is not easy, as caffeine can offer both benefits and risks.

Both tea and coffee contain beneficial antioxidants, and caffeine can help increase alertness, boosting learning and physical activity.

However, in some people, caffeine can increase blood pressure. Therefore, the overall effect can only be clearly determined through large-scale randomized trials.

Researchers estimate that about half of all dementia cases globally could be prevented or delayed if risk factors such as obesity, smoking, alcohol abuse, hearing loss, and hypertension were properly controlled.

Yu Zhang emphasized that tea and coffee should not be considered a "magic shield" for the brain. He recommended that maintaining a healthy lifestyle, regular exercise, a balanced diet, and adequate sleep remain fundamental factors for long-term cognitive health protection.