If by mid-afternoon you’re filling your fourth caffeinated cup, listen up: you could be in the coffee danger zone. A study released today in Mayo Clinic Proceedings found that drinking large amounts of coffee was linked to a much greater risk of dying in people under 55.
The magic number is 28 cups a week—which may sound like a lot, but not when you consider than the average coffee drinker consumes 3 cups a day. This was determined after researchers studied almost two decades worth of coffee use for more than 43,000 people, from ages 20-87.
First, the good news, from study co-author (and coffee drinker) Carl Lavie, MD, professor of medicine and medical director of Cardiac Rehabilitation and Prevention at Ochsner Clinical School in New Orleans. “We didn’t find any increased cardiovascular disease at any dose of coffee in any group,” he said. Coffee, it appears, is safe for your heart.
But when the team looked at non-cardiovascular mortality, death showed a clear pattern. Men and women under the age of 55 who drank more than 28 cups per week had an increased mortality risk greater than 50%. (Over 55? Lucky you: the team found no negative effects from any dose of coffee in your age range.)
The team didn’t assess what kind of non-cardiovascular mortality afflicted coffee drinkers more. But cancer is the leading cause of non-cardiovascular mortality, Dr. Lavie said, and he hopes to dig deeper into those numbers.
It’s worth noting that the study can’t show cause and effect between 28-cups a week and a higher risk of death; though the researchers controlled for many variables, like smoking and fitness, they didn’t control for others like stress levels of chaotic lifestyles. Still, the association is cause for concern, Dr. Lavie said. “It at least raises a signal that there could be some toxicity with very high amounts of coffee.”
Before you banish your brew altogether, consider Dr. Lavie’s recent research review in last month’s Journal of the American College of Cardiology. “Coffee has a lot of good features,” he said. “Some data shows that it’s helping dementia, it’s helping depression, it’s maybe helping reduce the risk of stroke, and it’s helping asthma.” Plus, as the latest paper shows, it doesn’t appear to be hurting your heart.
“All the data accumulated suggest that small amounts of coffee, now up to probably 28 cups a week, appear to be safe,” he said. “It’s only at the high amounts where there’s a potential problem.”
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