People who drank more than one diet soda each day developed the same risks for heart disease as those who downed sugary regular soda, a large but inconclusive study found.
The results surprised the researchers, who expected to see a difference between regular and diet soda drinkers. It could be, they suggest, that even no-calorie sweet drinks increase the craving for more sweets, and that people who drink sodas probably have less-healthy diets overall.
The study's senior author, Dr. Vasan Ramachandran of Boston University, emphasized that the findings don't show diet sodas are a cause of increased heart-disease risks. But he said they show a surprising link that must be studied.
However, a nutrition specialist dismissed the study's findings on diet soda drinkers.
"There's too much contradictory evidence that shows that diet beverages are healthier for you in terms of losing weight that I would not put any credence to the result" on the diet drinks, said Barry Popkin of the University of North Carolina in Chapel Hill .
The researchers found that those who drank more than one soda per day -- diet or regular -- had an increased risk of metabolic syndrome, compared with those who drank less than one soda. Metabolic syndrome is a cluster of symptoms that increase the risk for heart disease including large waistlines and higher levels of blood pressure, blood sugar, cholesterol, and triglycerides.