In the beginning, the participants filled in questionnaires about their diet and other lifestyle habits. At the end of the study, 9,253 people had died.
Overall, the researchers found that people who drank moderate amounts of coffee during the study period were less likely to die, especially if they had a history of heart attack. Those who drank two or more cups a day were 39% less likely to die, compared to non-drinkers.
There was a smaller risk reduction in people with no history of heart problems or stroke.
Meanwhile, green tea looked protective in survivors of both stroke and heart attack: the more green tea they drank, the better.
Of course, coffee and green tea lovers can differ from non-drinkers in other ways. The researchers explained a number of alternative explanations – including exercise and diet, and whether people smoked or had high blood pressure.
And yet tea and coffee seemed beneficial.
Still, Freeman said there could be other more nuanced things going on: People who have time for seven cups of tea in their day, for example, have less stress in their lives.
It’s also unclear whether findings in a Japanese population would generalize to countries with different diets, said 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.
Van Horn said specific plant species – in the case of green tea, epigallocatechin gallate – are “increasingly recognized as important anti-inflammatory cardio-metabolic benefits.”
Like Freeman, Van Horn said 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.
More information
The American Heart Association is more about 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 department, department of preventive medicine, Northwestern University Feinberg School of Medicine, Chicago, and volunteer expert, American Heart Association, Dallas; Stroke, Feb. 4, 2021, online