Back off the barista? Coffee may heighten Alzheimer's symptoms

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It's not just cancer that could be lurking in your morning cup o' Joe.

Researchers in Spain have linked prolonged exposure to caffeine to worsening Alzheimer's symptoms, at least in mice.

Lead researcher Dr. Lydia Giménez-Llort of the Universitat Autònoma de Barcelona in Spain said coffee's big draw might increase the behavioral and psychological symptoms of dementia, including delusions, hallucinations, irritability, anxiety and depression.

Previous research has linked coffee to a lower risk of developing Alzheimer's, but for those who already have the disease, Gimenez-Llort's team found the effects could indeed be harmful.

The researchers studied the effects by giving mice caffeine-infused water. That's equivalent to a 1.5 mg daily dose in a mouse or approximately a 500 mg dose for humans — found in approximately five cups' worth of coffee.

“While health benefits of caffeine and coffee are increasingly recognized, there are also notable reports of adverse effects of especially high-dose caffeine, including a case report of psychotic symptoms in a patient with dementia,” the authors write. “Our study adds to the evidence for caffeine and other adenosine-receptor blockers have distinct physiological effects. Some ways to deal with these multi-effects are to optimize the dose, to use active substances in coffee other than caffeine, and to use synthetic drugs modeled after caffeine, such as subtype-selective adenosine receptor antagonists, rather caffeine itself.”

Results were published in Frontiers in Pharmacology.