A study which was published on-line in Circulation in Jul 2007 suggests that drinking more than one soft drink per day poses a 44% greater risk for developing metabolic syndrome as compared to drinking less than one soft drink per day.

Metabolic syndrome is a cluster of various risk factors, like elevated (but not yet over the limit) triglycerides and glucose levels and increased waist circumference, that increase the risk of heart disease, stroke and diabetes.

Consumption of soft drinks has doubled to tripled between 1977 and 2001, and so has obesity. This study was designed to find possible associations between soft drink consumption in adults and metabolic risks.

Metabolic syndrome was defined as the presence of three or more of the following risk factors:

• excess waist circumference
• high blood pressure
• elevated triglycerides (fats)
• low HDL cholesterol levels (low levels of "good" cholesterol)
• high fasting glucose levels.

Analysis of 6000 people free of metabolic syndrome at baseline revealed, that drinking more than one soft drink per day is associated with a 44% greater risk for developing the metabolic syndrome as compared to drinking less than one soft drink per day.

A somewhat surprising finding was that this was true for both diet and regular sodas. People who drank more than one diet soft drink per day increased their risk for metabolic syndrome by 53% compared to 62% in those, who drank more than one regular soft drink per day.

Overall, it is hard to distinguish between the impact of soft drink consumption and other lifestyle factors on the development of the metabolic syndrome. These results only show the co-existence of soft drink consumption and metabolic syndrome risk factors, while causality remains uncertain.

"Individuals who drink soda tend to have a greater intake of calories, they consume more saturated and trans fats, less fiber and dairy products, and have a more sedentary lifestyle," leading investigator Dr. Ravi Dhingra says. Diet soda might promote a dietary preference for sweeter foods while brown caramel in soda could be contributing to the increased risk of tissue damage and inflammation.

On average, people who consume soft drinks tend to have greater intake of calories, partly because these drinks are not satiating enough. The question of whether soft drinks alone cause metabolic syndrome, or weather they are just part of a bigger problem of an unhealthy lifestyle, remains unanswered.

Source: The Choice of a Metabolic Syndrome Generation: Soft Drink Consumption Associated With Increased Metabolic Risk (Medscape)