“Evidence is building that caffeine might be the first dietary component able to protect against Alzheimer’s disease,” says Gary Arendash of Arizona State University.
“In mice bred to develop the disease, caffeine not only protects against inevitable memory impairment,” he explains, “but it also substantially decreases the amount of beta-amyloid, the bad protein in the brain that many researchers believe is the root cause of Alzheimer’s.”
The few human studies have been inconsistent.
For example, in a Hawaiian study that tracked nearly 3,500 middle-aged men for 25 years, those who reported consuming at least 400 milligrams of caffeine a day were 55 percent less likely than those who said they consumed less than 140 mg a day to have the brain lesions characteristic of dementia at their death. However, they were no less likely to be diagnosed with dementia during their lifetime.
That kind of research can’t prove whether or not caffeine wards off Alzheimer’s in people. “To determine that, we need a clinical trial,” notes Arendash.
Sources: J. Alzheimers Dis. 20 (Suppl 1): S117, 2010. J. Alzheimers Dis. 23: 607, 2011.