Caffeine helps older women fight memory loss, study finds

Monday, July 26 2010

Scientists can't explain why it doesn't help men

Maria Kubacki, The Ottawa Citizen;
with files from Citizen News Services

Published: Tuesday, August 07, 2007

It wakes you up in the morning, and it might help you retain your memory as you age -- but only if you're a woman.

A daily dose of caffeine may help older women without dementia protect their memory, according to a study published in today's issue of Neurology, the medical journal of the American Academy of Neurology.

Women aged 65 and older who drank more than three cups of coffee a day -- or the equivalent in tea -- did better on memory tests than women who drank one cup or less, the study found.

The benefits of caffeine appear to increase with age. At 65, caffeine consumers were 30 per cent less likely to show a decline in memory than other women.

For women over 80, the results were even more dramatic: those who drank more than three cups of coffee (or equivalent) daily were 70 per cent less likely to have a failing memory.

The protective effect of caffeine was observed in tests involving verbal memory. However, caffeine consumption was not found to prevent dementia.

Scientists studied 7,000 dementia-free people -- 4,197 women and 2,820 men -- whose cognitive abilities and caffeine intake were tracked over four years.

The findings held up even after other factors that impact cognitive function were taken into account -- such as education, high blood pressure, cardiovascular disease and depression -- according to the study .

The researchers theorize that caffeine may block adenosine receptors, which in turn may prevent damage caused by beta-amyloid -- a toxic substance that accumulates in the brains of patients with Alzheimer's disease.

It's not clear why caffeine doesn't seem to have the same protective effect in men, said the study's lead author, Dr. Karen Ritchie of the French National Institute for Health and Medical Research. Caffeine may be processed differently by women and men, she said.

Dr. Ritchie hopes a followup with the study participants in the French cities of Montpellier, Dijon and Bordeaux next year will show that even if caffeine can't prevent Alzheimer's disease, it may help increase the length of time between early signs of cognitive decline and the onset of dementia.

However, further study is needed before scientists can advise women to ramp up their caffeine intake, she cautioned. "Please don't everybody rush out and start drinking coffee," she said.

Caffeine can increase blood pressure, she explained -- which in itself can affect cognitive function.

Other known risks associated with caffeine are anxiety and increased heart rate, according to caffeine expert Ahmed el-Sohemy, Canada Research Chair in Nutrigenomics at the University of Toronto.

And while the French study showed a correlation between caffeine consumption and protection against cognitive decline, it did not demonstrate a cause and effect relationship, he said.

Other factors may be involved. His own research, published in the July issue of the American Journal of Clinical Nutrition, suggests that "those who drink a lot of caffeine are genetically different from those who don't."

The genetic difference is related to the adenosine receptor -- the same receptor pinpointed by the French scientists.

Meanwhile, scientists have discovered that Alzheimer's disease and glaucoma may be related, saying optical exams may someday detect dementia -- and mental-health drugs may treat eyes.

The scientists studied rats with surgically induced glaucoma, finding that proteins involved in Alzheimer's may cause nerve-cell death in eyes. The animals were given medicines used to combat beta amyloid, a substance deemed important in dementia.

The report was released today by the Proceedings of the National Academy of Sciences.

Scientists didn't know beta amyloid was involved in glaucoma before now, said the lead researcher, Francesca Cordeiro, a professor at the ophthalmology institute at the University of London. The discovery opens avenues for research into both glaucoma and Alzheimer's, she said.

"Well, the question is now, can you diagnose Alzheimer's through the eye?" she said. "I suspect you can."

Ms. Cordeiro and her colleagues tested treatments that block the buildup of beta amyloid, including Wyeth and Elan Corp.'s experimental drug Bapineuzumab, on rats. The combination of several drugs worked best to prevent glaucoma, and may suggest new avenues for treatment of Alzheimer's, she said.

© The Ottawa Citizen 2007

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