Sugary Drinks and Sodas Linked to Increased Diabetes, Metabolic Syndrome

Shelley Wood

October 29, 2010

October 29, 2010 (Boston, Massachusetts) — In the effervescent debate over whether sugary drinks may be upping rates of cardiometabolic diseases, those in favor of creative ways to limit consumption of sugar-sweetened beverages have some new ammunition.

In a new meta-analysis published in the November 2010 issue of Diabetes Care, Dr Vasanti S Malik (Harvard School of Public Health, Boston, MA) and colleagues report that consumption of just one or two sugar-sweetened beverages per day is associated with a 26% greater risk of developing type 2 diabetes and a 20% increased risk of developing metabolic syndrome [1].

"This is definitely an overlooked issue," senior author on the study, Dr Frank Hu (Harvard School of Public Health), told heartwire . "This hasn't been on the radar screen of nutritionists, diabetologists, or cardiologists, but the evidence, I think, is mounting that soft drinks are a very important risk factor for cardiometabolic disease and weight gain. I strongly encourage cardiologists and other clinicians to ask about their patients' dietary habits, especially something like soft-drink consumption, which can be easily assessed and modified."

Diabetes Risk From Two or Three Drinks Similar to Effects of Smoking

Malik, Hu, and colleagues combined data from 11 studies looking at either metabolic syndrome or diabetes and sugar-sweetened–beverage consumption, then analyzed the results based on whether patients reported drinking no sugar-sweetened drinks or drinking more than one or two per day. In addition to showing statistically significant increased risks of both metabolic syndrome and diabetes in association with soft-drink consumption, researchers also demonstrated a dose response, with a roughly 25% increase in risk associated with each additional 12-oz serving of sugar-sweetened beverage per day.

This is definitely an overlooked issue.

To put this in perspective, Hu said, smoking is associated with roughly a 30% to 40% increased risk of developing diabetes. "So for those who drink two to three sodas per day, their risk of developing type 2 diabetes would be increased by 30% to 40%, which is not very different from the increased risk associated with cigarette smoking."

Hu also emphasized that some but not all of the effects of sugary-drink consumption on diabetes or metabolic syndrome seem to be mediated through the increased calories and excess pounds. In an analysis that controlled for both energy intake and adiposity, a significantly increased risk of both diabetes and metabolic syndrome remained, the authors note.

"There is interesting evidence from clinical trials and animal experiments that higher amounts of fructose may directly contribute to components of the metabolic syndrome," Hu said. "For example, high-fructose corn syrup has been associated with increased risk for adiposity, increased triglycerides, and decreased HDL. So it's possible that the adverse effects of soft drinks on diabetes we observed in this meta-analysis are due to the combination of excess caloric intake but also some unique metabolic effects of fructose and other components of soft drinks."

Jury Still Out on Diet Drinks

As for whether soda junkies could just switch to artificially sweetened drinks, Hu was cautious, noting that some studies have actually pointed to an increased risk of metabolic disease among people regularly drink diet sodas.

Overall, he said, "the jury is still out in terms of the long-term health effects of artificial sweeteners, so I would be cautious about making public-health recommendations to replace regular soda with diet soda. But certainly we have other healthier options, such as water or nonsweetened tea or coffee."

The new analysis comes as many US cities and states are introducing "soda taxes" on sugar-sweetened beverages in the hopes of curbing consumption and, in some high-profile cases, trying to make sodas and sugary drinks ineligible for purchase using food stamps [2].


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