If you can’t function on less than three cups of coffee a day, we’re here to say once more, “It’s all good.” Just two weeks ago, java lovers rejoiced after learning that coffee drinkers tend to live longer than those who abstain. Now, another (much smaller) study has found that people older than 65 who drink about three cups of joe a day can avoid the onset of Alzheimer’s disease.
The link between caffeine and protection against Alzheimer’s isn’t new, but this study is promising in that it provides direct human evidence; previous studies linking the two have been performed on lab mice.
The study involved 124 people ages 65 to 88 who suffered from mild cognitive impairment. Fifteen percent of people with MCI are likely to be diagnosed with Alzheimer’s later in life. Researchers monitored the individuals for two to four years.
They found that there was a critical caffeine level of 1,200 ng/ml in individuals’ blood samples that determined whether their MCI became full-blown dementia or Alzheimer’s disease later. Those who had less than 1,200 ng/ml progressed to dementia, while subjects who had blood caffeine levels higher than the critical level did not develop the memory-impairing disease.
Researchers said the MCI patients who had blood caffeine levels greater than 1,200 ng/ml even before the study began were associated with a 100 percent chance of avoiding progression to dementia during the two- to four-year period. They drank about three cups per day.
They also noted that coffee appeared to be the only or major source of caffeine for these individuals.
So how does caffeine work its magic? The stimulant suppresses levels of certain enzymes that are required for an abnormal human protein that is found in the brains of people who develop Alzheimer’s.
However, researchers did note some caveats to their study. While a “key strength” was that they measured blood caffeine levels, it was also a limitation. The blood samples were only taken at the beginning of the study, and they did not ask the participants when they last had caffeine before taking their blood. Dietary and lifestyle habits were not noted, either.
“We are not saying that moderate coffee consumption will completely protect people from Alzheimer’s disease,” the study’s lead author, Dr. Chuanhai Cao, said in a statement. “However, we firmly believe that moderate coffee consumption can appreciably reduce your risk of Alzheimer’s or delay its onset.”
The full study was published in the Journal of Alzheimer’s Disease.