Drinking your morning coffee while thinking about your neurons, the idea seems almost too good. Dementia, of which Alzheimer’s disease is the most common cause, worries more and more families as the population ages. For a long time, the role of coffee remained unclear, between cardiovascular concerns and suspicions of protective effects.
But a large American study published in the journal
JAMA suggests, however, that moderate consumption of
coffee or caffeinated tea could reduce the risk of dementia and slow the decline of cognitive functions.
Coffee, tea and dementia risk: a 40-year study
Researchers followed 131,821 adults for up to 43 years. Participants in the Nurses’ Health Study and Health Professionals Follow-Up Study cohorts, without dementia, cancer or Parkinson’s disease at baseline, regularly completed questionnaires about their diet. The researchers compared the intake of coffee, tea, decaffeinated coffee and total caffeine to subsequent diagnoses of dementia, complaints of memory problems and tests of memory and attention in a portion of the volunteers.
They documented 11,033 cases of dementia. People who consumed the most caffeine had about an 18% lower risk than those who drank very little, with fewer complaints of cognitive decline (7.8% versus 9.5%) and slightly better test scores. For Daniel Wang, of Harvard Medical School, “Our study suggests that drinking caffeinated coffee or tea may be a piece of the dementia prevention puzzle“.
Why 2 to 3 cups of coffee a day seems ideal
Dose-response analysis shows that the risk reduction is greatest around 2 to 3 cups of caffeinated coffee per day, or 1 to 2 cups of tea. Beyond that, profits mostly seem to stabilize. The results were similar in men and women and regardless of genetic risk profile: “We observed the same benefits in people at low or high genetic risk of dementia“.
To explain these results, researchers point to caffeine and other compounds like polyphenols, which can reduce inflammation and cell damage. Decaffeinated coffee, deprived of caffeine, did not show a significant effect. The risk reduction remains modest, and the study is observational. Dr. Wang is also an Assistant Professor in the Department of Nutrition at Harvard Chan School”Although our results are encouraging, it is important to remember that the observed effect is modest and that there are many ways to preserve cognitive functions with age. Our study suggests that consumption of caffeinated coffee or tea may be one element among others.”.
What can you actually do with your coffee consumption?
Early prevention is particularly crucial for dementia, as current treatments are limited and generally provide only modest benefit once symptoms appear. But specialists advise against relying solely on coffee: it is better to stick to around 2 to 3 cups per day if you can tolerate it, avoiding drinking it in the evening. Céline Gounder recalls that the prevention of dementia is mainly based on exercise, a healthy diet, weight control and the fight against hypertension. However, a recent study showed that a certain type of brain training could reduce the risk of dementia by 25%. To find out more, discover our article “Alzheimer’s: specific brain training reduces the risk by 25%”.