Over-Perked: Excess Coffee Does Not Support Brain Health in the Long Run

I don’t know about you, but when I wake up, I make coffee to jump-start the day. But that’s not all the coffee I drink. I often have some after lunch, when I go to work at a cafe, or sometimes when meeting a friend to chat. Heck, sometimes I even have it after dinner for one last boost to finish off the day. So, what’s all this coffee doing to my brain?

It turns out that this habitual coffee consumption, although giving me some buzzing energy in the short term, isn’t great for my brain health in the long term, according to new research from the University of South Australia. Using information from nearly 400,000 participants, this research team investigated the link between habitual patterns of coffee consumption and brain health, finding that high coffee consumption (more than 6 cups) was linked to smaller brains and higher odds for poor brain health in the long run.

“We consistently found that higher coffee consumption was significantly associated with reduced brain volume,” says lead researcher and UniSA Ph.D. candidate Kitty Pham.

Buzzinga: Is Habitual Coffee Bad for the Brain?

Coffee is among the most popular non-alcoholic beverage after water. But Pham says, “With global consumption being more than nine billion kilograms a year, it's critical that we understand any potential health implications.” 

Although unique in flavor, coffee is often sought after because it contains caffeine, a central nervous system stimulant. Caffeine is known to have broad physiological influences, affecting sleep patterns, mood, motor activity, heart rate, body core temperature, and oxygen consumption. Along these lines, research has shown that there are mechanisms that could mediate a potential role of coffee on brain shape and size, posing a risk to brain health. The question becomes whether this is happening in the brains of many people.

High Coffee Consumption Affects Brain Health

The research team dove into data from hundreds of thousands of people (age 37 to 73) from the UK Biobank study, consisting of all sorts of measurements, such as brain volume from MRIs and self-reported coffee consumption as part of a touchscreen questionnaire. Pham and colleagues then divided these participants into categories ranging from non-coffee drinkers and decaffeinated coffee drinkers to coffee consumers bucketed by the number of cups they drank. 

The University of South Australia researchers found that ​​higher coffee consumption was linearly associated with smaller total brain volumes, meaning that with increasing amounts of coffee consumption, the more the brain shrunk. Specifically, both grey matter and white matter — the areas of the brain where the bodies of nerve cells and their projections reside, respectively — shrunk as well as the brain region associated with learning and memory called the hippocampus. While this study cannot confirm the underlying causality between caffeinated coffee and brain health, these results warrant carefully controlled studies to clarify the beneficial and adverse effects of coffee on the brain.

To Coffee or Not to Coffee, That Is the Question

Perhaps you’re asking yourself, well, did the study have to do with caffeine or coffee itself? Can I just switch over to decaffeinated coffee if the issue is caffeine, or if it isn’t the issue, can I switch over to tea, soda, or energy drinks?

Senior investigator and Director of UniSA's Australian Centre for Precision Health, Professor Elina Hyppönen, thinks that although the news may be a bitter brew for coffee lovers, it's all about finding a balance between what you drink and what's good for your health. "This research provides vital insights about heavy coffee consumption and brain health, but as with many things in life, moderation is the key," Prof Hyppönen says.

"Together with other genetic evidence and a randomized controlled trial, these data strongly suggest that high coffee consumption can adversely affect brain health. While the exact mechanisms are not known,” Prof Hyppönen says, “one simple thing we can do is to keep hydrated and remember to drink a bit of water alongside that cup of coffee.”

"Typical daily coffee consumption is somewhere between one and two standard cups of coffee. Of course, while unit measures can vary, a couple of cups of coffee a day is generally fine. However, if you're finding that your coffee consumption is heading up toward more than six cups a day, it's about time you rethink your next drink."

References:

Pham K, Mulugeta A, Zhou A, O'Brien JT, Llewellyn DJ, Hyppönen E. High coffee consumption, brain volume and risk of dementia and stroke [published online ahead of print, 2021 Jun 24]. Nutr Neurosci. 2021;1-12. doi:10.1080/1028415X.2021.1945858