Drinking three cups of coffee per day may delay Alzheimer's disease among older adults who are already showing signs of memory problems, a new study shows.
The findings show that people older than 65 who had higher blood levels of caffeine developed Alzheimer's disease two to four years later than their counterparts with lower caffeine levels.
Alzheimer's disease is the most common type of dementia. Symptoms include serious memory loss, confusion, and mood changes that develop gradually and worsen with time.
The new study included 124 people aged 65 to 88 who had mild cognitive impairment. About 15% of people with MCI develop full-blown Alzheimer's disease each year.
In the study, blood levels of caffeine were more than 50% lower among people with MCI who developed Alzheimer's during follow-up, when compared with their counterparts who did not worsen. Coffee was the main, or only source, of caffeine among people in the study.
No one with mild memory loss who later developed Alzheimer's had initial blood caffeine levels above 1,200 ng/ml. People whose memory loss did not worsen all had blood caffeine levels higher than this level.
"Continue to drink coffee," says researcher Chuanhai Cao, PhD, University of South Florida. "There is no reason to stop if you are experiencing memory problems."
There may even be a reason to start for people in their late 30s and up, he says. "Aim for an average of three, 8-ounce cups of coffee per day in the morning after eating breakfast."