Soft drinks are hard on the body

NEW YORK (Reuters Health) - The prevalence of metabolic syndrome is increased among middle-aged adults who regularly drink carbonated soft drinks, even soda that is calorie-free, new research suggests.

The metabolic syndrome is a cluster of several cardiovascular risk factors, including high blood pressure, high cholesterol, excess fat around the abdomen and glucose intolerance, a condition in which the body can no longer process sugar in the blood that often precedes diabetes.

Up until now, theories relating soft-drink consumption and metabolic syndrome have been based primarily on the high sugar content, Dr. Ramachandran S. Vasan, at Boston University School of Medicine, and associates note in their report, published in the Circulation: Journal of the American Heart Association.

To further evaluate this relationship, the authors analyzed data from subjects in the Framingham Heart Study who were in their mid-50s participated in two evaluations between 1998 and 2001 and were free of cardiovascular disease when the study began.

In their analysis, the researchers found that the subjects who consumed one or more soft drinks per day had a 48-percent higher prevalence of metabolic syndrome compared to whose who drank less.

In the second analysis, subjects who drank soft drinks had 44-percent higher risk of metabolic syndrome. Drinking soft drinks also increased the incidence of each component of the metabolic syndrome.

Previous work has shown that consumption of soft drinks is associated with overall dietary behavior, with a diet high in calories and fat, and low in fiber. However, Vasan and associates point out, even after accounting for known risk factors such as diet, smoking and physical activity, the association between soft drink consumption and metabolic syndrome remained statistically significant.

However, because this was an observational study, Vasan's group could not discern any evidence that drinking soft drinks actually caused the metabolic syndrome.

"Public health policy measures to limit the rising consumption of soft drinks in the community may be associated with a lowering of the burden of metabolic risk factors in adults," they conclude.

SOURCE: Circulation, July 24, 2007.