At the outset, the participants completed questionnaires on their diets and other lifestyle habits. By the end of the study, 9,253 people had died.
In general, the researchers found, people who drank moderate amounts of coffee were less likely to die during the study period — especially if they had a history of heart attack. Those who drank two or more cups per day were 39% less likely to die, versus non-drinkers.
There was a smaller risk reduction among people with no history of heart problems or stroke.
Meanwhile, green tea looked protective among both stroke and heart attack survivors: The more green tea they drank, the better.
Of course, coffee and green tea lovers may be different from non-drinkers in other ways. The researchers accounted for a number of alternative explanations — including exercise and diet habits, and whether people smoked or had high blood pressure.
And still, tea and coffee seemed beneficial.
Still, Freeman said there could be other, more nuanced things going on: People who have time in their day for seven cups of tea might have less stress in their lives, for instance.
It’s also unclear whether findings in a Japanese population would generalize to countries with different diets, according to Linda Van Horn, an expert with the American Heart Association.
Tea drinkers in the study tended to have a healthy intake of fish and vegetables, noted Van Horn, who is also a professor of preventive medicine at Northwestern University in Chicago.
Those cautions made, Van Horn said that specific plant compounds — in the case of green tea, one called epigallocatechin-gallate — “are increasingly being recognized as having important anti-inflammatory cardio-metabolic benefits.”
Like Freeman, Van Horn said that replacing sugary drinks with green tea would be a wise move. But she also agreed that a diet full of fruits, vegetables, fish, whole grains and “good” fats is key.
The American Heart Association has more on healthy eating.
SOURCES: Andrew Freeman, MD, director, cardiovascular prevention and wellness, and associate professor, National Jewish Health, Denver; Linda Van Horn, PhD, RDN, professor and chief, nutrition division, department of preventive medicine, Northwestern University Feinberg School of Medicine, Chicago, and volunteer expert, American Heart Association, Dallas; Stroke, Feb. 4, 2021, online