2 to 3 Cups of Caffeinated Coffee a Day Linked to Lower Dementia Risk

A large new analysis found that people who drank two to three cups of caffeinated coffee a day had lower chances of developing Alzheimer’s disease or other forms of dementia than their peers who drank little or no coffee. Drinking one to two cups of caffeinated tea a day was also associated with a lower risk of dementia, though decaffeinated beverages did not provide the same brain benefits.

For the analysis, researchers looked at health data from 131,821 health professionals who were enrolled in two large studies spanning many years: women in the Nurses’ Health Study and men in the Health Professionals Follow-Up Study. None had Alzheimer’s disease or other serious health problems at the start of the study period, when most participants were in their 40s or 50s, and researchers tracked their health for up to 43 years.

Participants filled out detailed questionnaires about their food and drink intake every two to four years, including how much regular or decaf coffee and tea they drank on a typical day. They also had regular tests of thinking and memory skills.

During the study period, 11,033 participants developed Alzheimer’s disease or other forms of dementia. The researchers considered various risk factors that could influence brain health and dementia risk, including medical conditions, diet, medications, years of schooling, family history of Alzheimer’s disease, body mass index, smoking and depression.

After controlling for these factors, the researchers calculated that compared to those who drank little or no coffee, people who drank two to three cups of regular coffee a day over many years had about a 19 percent lower dementia risk. Those who drank at least one cup of caffeinated tea daily had about a 14 percent lower risk of dementia.

Coffee drinkers also tended to score higher on general tests of memory and thinking skills, although any benefits were modest. They were also less likely to report that they thought they were suffering from memory problems, which may be an early warning sign of impending Alzheimer’s disease. Drinking decaffeinated coffee did not have an effect on dementia risk or cognitive abilities.

People did not seem to get additional benefits from drinking more than two to three cups of coffee or one to two cups of tea a day. The study showed only an association between coffee and reduced dementia risk and cannot prove cause and effect. The findings were published in JAMA.