At the beginning, the participants completed questionnaires about their diets and other lifestyle habits. At the end of the study, 9,253 people died.
In general, the researchers found that 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 a day were 39% less likely to die compared to non-drinkers.
There was a smaller risk reduction among people with no history of heart problems or stroke.
Meanwhile, green tea seemed protective among both survivors of a stroke and heart attack: the more green tea they drank, the better.
Of course, coffee and vegetable tea lovers may differ from non-drinkers in other ways. The researchers were responsible for a number of alternative explanations – including exercise and dietary habits, and whether people smoke or have high blood pressure.
And yet, tea and coffee seemed beneficial.
However, Freeman said other, more nuanced things could happen: people who have time for seven cups of tea on the day, for example, have less stress in their lives.
According to Linda Van Horn, an expert from the American Heart Association, it is also unclear whether findings in a Japanese population would generalize to countries with different diets.
Tea drinkers in the study tended to have a healthy intake of fish and vegetables, says Van Horn, who is also a professor of preventive medicine at Northwestern University in Chicago.
Van Horn said specific plant compounds – in the case of green tea, one called epigallocatechin gallate – “are increasingly recognized as important anti-inflammatory cardio-metabolic benefits.”
Like Freeman, Van Horn said replacing sweet drinks with green tea would be a wise move. But she also agrees that a diet full of fruits, vegetables, fish, whole grains and ‘good’ fats is key.
More information
The American Heart Association has more about healthy eating.
SOURCES: Andrew Freeman, MD, Director of Cardiovascular Prevention and Wellness, and Associate Professor, National Jewish Health, Denver; Linda Van Horn, PhD, RDN, professor and head, nutrition department, department of preventive medicine, Northwestern University Feinberg School of Medicine, Chicago, and volunteer expert, American Heart Association, Dallas; Stroke, February 4, 2021 online