New research monitoring the memory and thinking processes of older people found that those with higher blood caffeine levels avoided the onset of Alzheimer’s disease in the two-to-four years of study follow-up. Coffee was the major or only source of caffeine for these individuals.
Researchers from the University of South Florida and the University of Miami say this case control study (which involved 124 people aged between 65 and 88) provides the first direct evidence that caffeine/coffee intake is associated with a reduced risk of dementia or delayed onset.
The results suggest that older people with mild memory impairment who drink moderate levels of coffee, about 3 cups a day, will not convert to Alzheimer’s disease or at least will experience a substantial delay before converting to Alzheimer’s. The findings from this study, along with the team’s earlier work using Alzheimer’s mice, are consistent in indicating that moderate daily caffeine/coffee intake throughout adulthood is associated with protection against Alzheimer’s disease later in life.
The study indicates the protective effect probably even occurs in older people with early signs of the disease, called mild cognitive impairment, or MCI. Patients with MCI already experience some short-term memory loss and show initial Alzheimer’s pathology in their brains. Each year, about 15 percent of MCI patients progress to full-blown Alzheimer’s disease. The researchers focused on participants with MCI as many were destined to develop Alzheimer’s within a few years.
At the beginning of the study blood caffeine levels were substantially lower (51% less) in participants diagnosed with MCI who progressed to dementia during the two-to-four year follow-up period than in those whose mild cognitive impairment remained stable over that same time period.
None of the participants with MCI who later developed Alzheimer’s had initial blood caffeine levels above a critical level of 1200 ng/ml – equivalent to drinking several cups of coffee a few hours before the blood sample was taken. In contrast, many with stable MCI had blood caffeine levels higher than this critical level. None of the MCI patients with blood caffeine levels above the critical level progressed to Alzheimer’s disease during the two to four years follow up.
The researchers believe higher blood caffeine levels indicate habitually higher caffeine intake, most likely through coffee. Caffeinated coffee appeared to be the main, if not the only, source of caffeine in the memory-protected MCI patients because they had the same profile of blood immune markers as Alzheimer’s mice given caffeinated coffee. Alzheimer’s mice given caffeine alone or decaffeinated coffee had a very different immune marker profile.
Since 2006, the research team has published several studies investigating the effects of caffeine/coffee given to Alzheimer’s mice. Most recently, they reported that caffeine interacts with an as yet unidentified component of coffee to boost blood levels of a critical growth factor that seems to fight off the Alzheimer’s disease process.
The researchers are not claiming that moderate coffee consumption will completely protect people from Alzheimer’s disease but they do believe moderate daily consumption of caffeinated coffee can appreciably reduce the risk of Alzheimer’s or delay its onset.
This study was published on June 5th 2012 in the Journal of Alzheimer’s Disease and online at http://health.usf.edu/nocms/publicaffairs/now/pdfs/JAD111781.p