Although the underlying mechanism remains unclear, available evidence suggests that the main defect in the development of GDM is relatively diminished insulin secretion coupled with pregnancy-induced insulin resistance. The researchers discuss a number of explanations of their findings. Consuming a large amount of sugar-sweetened beverages could contribute to a high glycemic load (GL) by providing a large amount of rapidly absorbable sugars. High-GL foods induce a greater plasma glucose response after eating which can result in insulin resistance and impaired beta cell function. (Pancreatic beta cells make insulin.) In addition, higher sugar intake itself may lead to impaired pancreatic cell function.

"We don't know why significant association was only found in sugar-sweetened cola, but not other types of sugar-sweetened beverages - fruit drinks, other soft drinks, etc.," says Dr. Chen. "One of the explanations could be the tremendous popularity of cola in the US."

Previous studies in children and adults have shown that regular consumption of sugary drinks is associated with excess caloric intake, greater weight gain, and increased risk of obesity. Sugary drinks have also been linked to type 2 diabetes and other metabolic disorders.

"This is the first study on the impact of sugar-sweetened beverages on GDM risk," notes Dr. Chen. "This finding is important because sugar-sweetened beverages are the leading source of added sugars in the American diet, particularly in the age group most likely to conceive. Cutting down sugary drinks is clearly an important way to reduce this common pregnancy complication."

According to the National Health and Nutrition Examination Survey 1999-2001, from 1977 to 2001, soft drink intake increased from 4.1% to 9.8% for 19- to 39-year-olds. In percentage terms, soft drink intake was highest among this age group in comparison to other ages.

Source: Louisiana State University Health Sciences Center