Three cups of coffee per day may have “significant” negative effect on Alzheimer’s symptoms, study suggests

04 Apr 2018 --- A study has found that the long-term consumption of caffeine worsens some neuropsychiatric symptoms experienced by most Alzheimer’s patients. The research, published in Frontiers of Psychology, suggests the most exacerbated symptoms are neophobia (fear of everything), anxiety-related behaviors and emotional and cognitive flexibility.

Memory problems are the hallmarks of Alzheimer’s disease, but it also characterized by distressing neuropsychiatric symptoms. These symptoms, known as Behavioral and Psychological Symptoms of Dementia (BPSD) include anxiety, depression, hallucinations, paranoia and sundowning. These symptoms may be strongly present already in the first stages of the disorder.

Significantly, coffee or caffeine has been suggested as a strategy in dementia prevention, both in patients with Alzheimer's disease and in the normal ageing processes. This is due to its action in blocking molecules – adenosine receptors – which may cause dysfunctions and diseases in old age.

To address these speculations, the study was conducted on normal aging mice and familial Alzheimer’s model's mice. The research spanned from the onset of the disease up to more advanced stages.

“The mice develop Alzheimer's disease in a very close manner to the human patients with an early-onset form of the disease. They not only exhibit the typical cognitive problems but also a number of BPSD-like symptoms, so it is a valuable model to address whether the benefits of caffeine will be able to compensate its putative negative effects,” explains Raquel Baeta-Corral, first author of the research.

“We simulated a long oral treatment with a very low dose of caffeine (0.3 mg/mL) equivalent to three cups for a human coffee-drinker to answer a question which is relevant for patients with Alzheimer's, but also for the ageing population in general, and that in humans would take years to be solved since we would have to wait until the patients were aged,”says Dr Björn Johansson, research and physician at the Karolinksa University Hospital.

Results demonstrated that caffeine worsened neuropsychiatric symptoms in mice with Alzheimer's disease. Significant effects were found in the majority of variables studies, especially in relation to neophobia (a fear of everything new), anxiety-related behaviors, and emotional and cognitive flexibility. Furthermore, their learning and memory got little benefit from caffeine.

“Our observations of adverse caffeine effects in an Alzheimer´s disease model together with previous clinical observations suggest that an exacerbation of BPSD-like symptoms may partly interfere with the beneficial cognitive effects of caffeine. These results are relevant when coffee-derived new potential treatments for dementia are to be devised and tested,” says Dr. Lydia Giménez-Llort, a researcher from the INc-UAB Department of Psychiatry and Legal Medicine and lead researcher of the project. 

Alzheimer’s disease currently has no complete cure, but the studies seeking methods to treat, or alleviate symptoms, or even the offset of the disease are common. NutritionInsight as previously reported on research that links the gut microbiome – the population of microorganisms living in the gastrointestinal tract – and brain diseases such as Parkinson's and Alzheimer's, including potential new ways to track and treat these diseases.