At the beginning, participants answered 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 those who did not drink.
There was less risk reduction among people without a history of heart problems or stroke.
Meanwhile, green tea seemed protective among stroke and heart attack survivors: the more green tea they drank, the better.
Of course, coffee and green tea lovers can be different from those who don’t drink in other ways. The researchers explained a number of alternative explanations – including exercise and eating habits, and whether people smoked or had high blood pressure.
Still, tea and coffee seemed beneficial.
Still, Freeman said there could be other, more nuanced things going on: people who have time in the day for seven cups of tea may have less stress in their lives, for example.
It is also unclear whether the findings in a Japanese population would generalize to countries with different diets, according to Linda Van Horn, an expert at the American Heart Association.
Tea drinkers in the study tend 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.
With these precautions, Van Horn said that plant-specific compounds – in the case of green tea, an epigallocatechin-gallate – “are increasingly being recognized as having important cardio-metabolic anti-inflammatory benefits.”
Like Freeman, Van Horn said replacing sugary drinks with green tea would be a smart move. But she also agreed that a diet rich in fruits, vegetables, fish, whole grains and “good” fats is the key.
More information
The American Heart Association has more information 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, division of nutrition, department of preventive medicine, Northwestern University Feinberg School of Medicine, Chicago, and volunteer specialist, American Heart Association, Dallas; Leakage, February 4, 2021, online