Harvard Heart Letter

Soft drinks found to increase stroke risk

Study implicates both diet and sugar-sweetened sodas.

Pop. Soda. Cola. No matter what you call soft drinks, they are among the unhealthiest beverages in this country. Sugar-sweetened soft drinks have been linked with coronary artery disease and its risk factors, including obesity, high blood lipid levels, hypertension, and diabetes. And although low-calorie sodas have not been extensively studied, there's new information that sugar-sweetened and diet soft drinks alike may increase the risk of stroke (American Journal of Clinical Nutrition, May 2012).

The finding comes from an analysis of two long-term studies, the Nurses' Health Study, which began in 1976 with 121,700 women, and the Health Professionals Follow-Up Study, which started in 1986 with 51,529 men. Every few years, participants in both studies complete questionnaires about their health and diet. This allows researchers to see relationships between food choices and medical conditions that arise over time.

In this study, researchers looked at the number and type of strokes that occurred over a 22- to 28-year period. They compared this information with the consumption of low-calorie caffeinated colas, caffeine-free colas, other low-calorie soft drinks and their sugar-sweetened counterparts. All findings were adjusted for factors that might influence stroke risk, such as vegetable and red meat intake, smoking, hormone replacement therapy, age, parental history of heart attack and stroke, and exercise.

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