Three cups of coffee a day to help you prevent dementia

In a case-control study, researchers at the University of South Florida and the University of Miami found that people over the age of 65 with higher levels of caffeine in their blood were less likely to develop Alzheimer's disease within 2 to 4 years. Coffee appears to be the main source of caffeine in the blood of these subjects. This is the first direct evidence that caffeine / coffee intake is associated with a reduced risk or delay in onset of dementia. The study was published in advance in the online edition of the Journal of Alzheimer's Disease.

The researchers recruited 124 elderly subjects aged 65 to 88 in Tampa and Miami with mild cognitive impairment-early signs of Alzheimer's disease. The results showed that patients who developed dementia during a 2-4-year follow-up had a baseline blood caffeine concentration of only 49% of those whose cognitive function remained stable.

None of the patients who later developed Alzheimer's had a baseline blood caffeine concentration higher than 1200 ng/ml, which is equivalent to drinking multiple cups of coffee within hours before the blood sample was taken. In contrast, many people whose cognitive function remained stable had blood caffeine levels above this threshold, and none of those who reached this threshold developed Alzheimer's disease during the 2-4 year period.

Lead researcher Dr Chuanhai Cao of the University of South Florida said: "people with mild cognitive impairment have developed some short-term memory loss and initial brain pathological changes, and about 15% of these patients develop Alzheimer's disease each year. These findings suggest that older people with mild memory impairment who drink three cups of coffee a day are less likely to develop Alzheimer's disease, or at least much later. This study is consistent with our previous findings, suggesting that moderate daily intake of caffeine / coffee throughout adulthood can effectively prevent Alzheimer's disease in old age. "

The researchers believe that the concentration of caffeine in the blood is closely related to daily coffee intake, and that drinking coffee is at least the main source of caffeine in the blood, based on the fact that the immune markers in the blood of those whose cognitive function remains stable are the same as those of Alzheimer's mice who drink coffee. drinking non-caffeinated coffee causes mice to develop different immune characteristics.

Because patients with Alzheimer's disease begin to experience neurodegeneration 10 to 20 years before cognitive decline, the researchers stress that any intervention aimed at reducing the risk of Alzheimer's disease must be implemented before symptoms can be effective. "drinking a moderate amount of coffee every day seems to be the best dietary choice for long-term prevention of Alzheimer's disease."

In addition to Alzheimer's disease, moderate caffeine / coffee intake seems to reduce the risk of multiple diseases in the elderly, including Parkinson's disease, stroke, type 2 diabetes and breast cancer, but the supporting evidence comes from observational studies rather than control trials. A study published earlier this year in the New England Journal of Medicine tracked the health and coffee intake of more than 400,000 elderly people over a 13-year period. The results showed that coffee drinkers had a lower risk of dying from heart disease, lung disease, stroke, diabetes, infection and even accidents.