Coffee is a highly popular beverage worldwide, containing caffeine which is a central nervous system stimulant. In a study of 398,646 UK Biobank participants, high coffee consumption (more than six cups of coffee a day) was associated with smaller total brain volumes and 53% higher odds of dementia.
“Coffee is among the most popular drinks in the world. Yet with global consumption being more than nine billion kilograms a year, it’s critical that we understand any potential health implications,” said Kitty Pham, a Ph.D. candidate in the Australian Centre for Precision Health at the University of South Australia.
“This is the most extensive investigation into the connections between coffee, brain volume measurements, the risks of dementia, and the risks of stroke — it’s also the largest study to consider volumetric brain imaging data and a wide range of confounding factors.”
“Accounting for all possible permutations, we consistently found that higher coffee consumption was significantly associated with reduced brain volume — essentially, drinking more than six cups of coffee a day may be putting you at risk of brain diseases such as dementia and stroke.”
Pham and colleagues conducted prospective analyses of habitual coffee consumption on 398,646 UK Biobank participants (age 37-73 years), including 17,702 participants with MRI information.
They examined the associations with brain volume, odds of dementia (4,333 incident cases) and stroke (6,181 incident cases).
There were inverse linear associations between habitual coffee consumption and total brain, gray matter, white matter and hippocampal volumes, but no evidence to support an association with white matter hyperintensity volume.
The association between coffee consumption and dementia was non-linear, with evidence for higher odds for non-coffee and decaffeinated coffee drinkers and those drinking over six cups a day, compared to light coffee drinkers.
After full covariate adjustment, consumption of over six cups a day was associated with 53% higher odds of dementia compared to consumption of one or two cups a day, with less evidence for an association with stroke.
“While 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,” said Professor Elina Hyppönen, a researcher in the Australian Centre for Precision Health at the University of South Australia and the South Australian Health and Medical Research Institute.
“This research provides vital insights about heavy coffee consumption and brain health, but as with many things in life, moderation is the key.”
“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, 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.”
The findings were published in the journal Nutritional Neuroscience.
Kitty Pham et al. High coffee consumption, brain volume and risk of dementia and stroke. Nutritional Neuroscience, published online June 24, 2021; doi: 10.1080/1028415X.2021.1945858