Your Favorite Morning Beverage Could Protect Against Dementia

Key Takeaways

• In a recent study, people who drank at least 2 cups of coffee or tea per day had a 38 percent and 36 percent lower chance, respectively, of developing dementia compared to people who didn't have a morning beverage.
• Results from a companion study suggest brain benefits may dwindle after 3 cups.
• The studies were observational, so they didn't show whether or how the coffee and tea themselves conferred these benefits.

If you're looking for more ways to stall cognitive decline, you might want to focus on your morning coffee or tea. That's because two new studies suggest that a daily cup or two of these beverages might be one way to promote brain health as you age.

One of the studies followed about 6,000 cognitively healthy adults for about seven years, starting when they were 68 years old on average. Over the past five or so years of follow-up, about 230 people developed dementia. But people who had at least two daily cups of coffee were 38 percent less likely to develop dementia than those who never drank coffee, and the risk was also 36 percent lower for tea drinkers than for people who never had tea.

"This is likely due to high amounts of polyphenols in these beverages," says Frank B. Hu, MD, PhD , a professor and the chair of the nutrition department at the Harvard T.H. Chan School of Public Health in Boston, who wasn't involved in the new studies. "Polyphenols are plant compounds that have been shown to have anti-inflammatory and antioxidant effects, which are beneficial for brain health."

The other study followed 8,451 cognitively healthy adults for about nine years, starting when they were at least 60 years old. This analysis focused on what's known as fluid intelligence, or abstract thinking and problem-solving skills - which naturally decrease with advancing age.

Researchers found that drinking 0 to 3 cups of coffee a day was associated with a significantly smaller decline in fluid intelligence than consuming four or more cups daily. With tea, however, they found that drinking one or more daily cups was linked to a smaller decrease in fluid intelligence than consuming no tea at all.

Caffeine Is Good for the Brain - in Moderation

"Fluid intelligence benefits from being able to focus well and think quickly, and I would expect that at moderate levels of caffeine consumption," says Glen Finney, MD , a neurology professor and the director of the memory and cognition program at the Geisinger College of Health Sciences in Danville, Pennsylvania, who wasn't involved in the new studies.

The amount of caffeine in these beverages might have something to do with their impact on brain function, Dr. Finney says.

"But it is possible to have too much of a good thing, and it may be that drinking very high levels of coffee could provide too much caffeine, leading to a drop-off in performance, as your brain might be in too much overdrive," Finney says.

Other substances in coffee might also be bad for brain health when consumed in excess, says Yu Chen, PhD, MPH , an epidemiology professor at the New York University Grossman School of Medicine in New York City, who wasn't involved in the new studies.

"Coffee might have other ingredients, like cafestol - which can raise cholesterol - that could negatively affect thinking," Dr. Chen says.

The Studies Had Limitations

Both studies were presented at the Alzheimer's Association International Conference in Toronto. Researchers provided only preliminary findings, and the results were not published in a medical journal, a process that typically involves an independent review of the findings by experts in the field.

Neither one of the studies was a controlled experiment designed to prove whether or how coffee or tea consumption might directly impact cognitive function or the odds of developing dementia. It's also not clear from the studies how much caffeine was in the coffee or tea people consumed.

"Different coffees and teas may have variable amounts of caffeine and other brain impacting substances, so knowing that would be helpful," Finney says.

In the first study, which focused on dementia risk, it wasn't clear how much caffeine played a role in the results. People who had at least 2 cups a day of caffeinated coffee were 34 percent less likely to develop dementia than participants who didn't drink coffee at all, while a similar amount of decaffeinated coffee was associated with a 51 percent lower dementia risk. But these differences were too small to rule out the possibility that they were due to chance.

It's possible that factors not presented with the preliminary findings - like what people ate, how much they exercised, and what underlying medical issues they had - might have contributed to the results.

"Both are observational studies, and thus it is important to take into account other factors related to coffee or tea consumption that may explain these findings, including their baseline health conditions," Dr. Hu says.

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Lisa Rapaport

Author

Lisa Rapaport is a journalist with more than 20 years of experience on the health beat as a writer and editor. She holds a master's degree from the UC Berkeley Graduate School of Journalism and spent a year as a Knight-Wallace journalism fellow at the University of Michigan. Her work has appeared in dozens of local and national media outlets, including Reuters, Bloomberg, WNYC, The Washington Post, Los Angeles Times , Scientific American , San Jose Mercury News , Oakland Tribune , Huffington Post, Yahoo! News, The Sacramento Bee , and The Buffalo News . See full bio See Our Editorial Policy Meet Our Health Expert Network