New research linking soda consumption with an increased risk of heart disease is sparking concern among nutrition researchers and physicians who say the findings could give consumers the wrong idea about their favorite fizzy beverages.
Carbonated soft drinks, rarely the darlings of nutrition research, have been implicated by previous research in childhood obesity, diabetes and other ills -- problems compounded by the growing consumption of these beverages in recent years.
Now a new study published in the current issue of the journal Circulation suggests that drinking a soda or more per day -- even if it's a diet soda -- is associated with an increase in other risk factors for heart disease.
The study's researchers report that those who said they drank a soda or more per day had a 31 percent greater chance of developing obesity, a 30 percent increased risk for gaining inches around the waist, a 25 percent chance of developing high blood sugar levels and a 32 percent greater chance of developing lower "good" cholesterol levels.
"This study further emphasizes the importance of lifestyle measures for preventing metabolic disease," said Ramachandran Vasan, senior author of the Framingham Heart Study and one of the authors of the current study.
But Vasan, who is also a professor of medicine at Boston University School of Medicine, added that the link found in the study between diet soda and heart ills was unexpected.
"This was sort of a surprising answer, as it did not seem to make a difference whether the soda was regular or diet," Vasan said. "Especially because we know that diet soda is a zero-calorie drink."
Vasan and others are concerned that the results of the study could be misinterpreted by the public as evidence of a direct link between soda consumption and an increase in heart risk.
"What we have here is an association, it does not really imply causality," Vasan cautioned.
"Clearly, a diet soda should not increase risk factors," said Dr. Dean Ornish, diet book author and clinical professor of medicine at the University of California at San Francisco. "It's almost certainly an association -- i.e., people who drink soft drinks probably are more likely to lead unhealthful lifestyles in other ways."
In other words, people who drink any kind of soda, diet or otherwise, may not be eating as healthily or exercising as often as those who stay away from them.
Few, after all, would likely report drinking a tall, cold glass of milk with a Big Mac and fries, or sucking down a liter of cola after a 5K run.
"There is no reason to think that soda -- as much as I do not think it should be a part of a healthy diet -- would cause heart disease," said Dr. Darwin Deen, associate professor of clinical epidemiology at the Albert Einstein College of Medicine. "But it comes as no surprise that people who do drink soda do other heart-harming things, thus creating an association between soda drinking and [heart disease]."
Other nutrition specialists agreed.
"Think about it: Soda is usually eaten with high-calorie fast food meals and high-calorie, high-fat snacks," said Keith Ayoob, a pediatric nutritionist at Albert Einstein College of Medicine. "Know anyone who eats fruit salad with soda? I rest my case."