Coffee May Worsen Certain Alzheimer's Disease Symptoms, Study Finds

A recent animal study published in Frontiers in Pharmacology suggests that coffee may worsen some anxiety-related symptoms of Alzheimer's disease. The findings could change perspective on the popular beverage, which is usually hailed for its health benefits.

Researchers added 0.3 milligrams per milliliter of caffeine to the drinking water of rats with a rodent model of Alzheimer's disease. This dosage is equivalent to a human drinking about five cups of coffee a day, Medical News Today reported. The caffeine was added when the rats were between 6 and 13 months of age. At 13 months, the mice were tested for their both behavioral and cognitive Alzheimer's symptoms.

While most associate Alzheimer's disease with its hallmark cognitive symptoms, such as worsening memory, the condition is also associated with a number of behavioral symptoms, such as increased depression and anxiety.

A cup of coffee over spills on a table. Caffeine equivalent to five cups of coffee a day worsened anxiety in rats with Alzheimer's disease. Christopher Furlong/Getty Images

Researchers found that caffeine had little effect on the rats' memory but seemed to increase the severity of their anxiety-like conditions. The Alzheimer's rats that drank caffeine displayed more anxiety symptoms, such as fear of unfamiliar objects, compared to rats who did not consume caffeine.

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Although coffee has been noted for its effects on improving memory and cognition, researchers noted that its potential to exacerbate other Alzheimer's disease symptoms may offset these benefits.

"These results confirm that caffeine, despite its everyday use and relative lack of government regulation, is a potent compound with multifaceted effects," the authors wrote.

Dr. Nikhil Palekar, medical director of the Stony Brook Center of Excellence for Alzheimer's Disease and director of geriatric psychiatry, told Newsweek that the effects of caffeine on anxiety are widely acknowledged. Palekar already advises his Alzheimer's patients to avoid caffeine if they are experiencing anxiety but added that saying caffeine worsens Alzheimer's disease may be an overstatement.

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"It doesn't mean that patients with Alzheimer's disease can't have coffee," said Palekar. "I don't think we can take it that far."

However, Palekar did point out that increased anxiety in Alzheimer's patients could also worsen other symptoms of the disease.

"Patients with increased anxiety and depression may have a harder time learning things and focusing, and overall their cognition may decline."

Palekar noted that the test should be translated to humans before making a decision on caffeine. "Human brains are more complicated than a mouse brain."