Drinking more than one soft drink daily, whether regular or diet, may increase risk factors for heart disease, according to the latest research from the Framingham Heart Study.
Thinking about a refill on that diet soda? Think again.
Drinking more than one soft drink daily, whether regular or diet, may increase risk factors for heart disease, according to the latest research from the Framingham Heart Study, being published this week in Circulation, the journal of the American Heart Association.
``In studies such as Framingham, we show guilt by association, we cannot state for a fact that soda is always the culprit,'' said Dr. Ramachandran Vasan, senior author of the Framingham Heart Study and professor of medicine at Boston University School of Medicine. ``What really struck us was that it didn't matter whether it was diet or regular soda that the participants consumed - the association with increased risk was present.''
The link between soft drinks and the risk factors is not new - previous studies examined regular soft drinks - but this latest study shows artificially sweetened diet sodas could also be harmful.
The Framingham study included nearly 9,000 person observations made in middle-aged men and women over four years at three different times.
At the start of the study period, researchers found that those who consumed more than one soft drink a day had a 48 percent increased prevalence of the metabolic syndrome - a cluster of cardiovascular disease and diabetes risk factors - compared to those drinking less than one soft drink daily.
Researchers then followed those who were free of the metabolic syndrome over the next four years. Those who consumed more than one soft drink a day were found to have a 44 percent higher risk of developing new-onset metabolic syndrome.
``Results also don't appear to be driven by the food that is being eaten with the soft drinks,'' Vasan said. ``We adjusted for saturated fat and trans-fat intake, dietary fiber consumption, total caloric intake, smoking and physical activity. We still observed a significant association.''
The cluster of cardiovascular disease and diabetes risk factors that comprise metabolic syndrome include excess waist circumference, high blood pressure, elevated triglycerides, low levels of high-density lipoprotein (also known as HDL or ``good'' cholesterol) and high-fasting glucose levels. The presence of three or more of the factors increases a person's risk of developing diabetes and cardiovascular disease.
For the purposes of the study, a serving was determined to be 12 fluid ounces, or one can of soda. Participants were asked specifically about cola drinks.
Researchers have three theories as to why soda consumption affected participants, Vasan said. A person who consumes a lot of liquid at one meal is less satiated and may go on to eat more at his or her next meal. The sweetness of soda, both regular and diet, may also cause a person to develop a dietary preference for sweeter food, which tends to have more calories.
Finally, the brown color of colas is obtained from caramel, which has been linked to inflammation and insulin resistance in lab animals.
The research also found that those who drank more than one soft drink a day had a 30-percent greater risk of developing new-onset obesity, a 30-percent increased risk of developing increased waist circumference, a 25-percent increased risk of developing high blood triglycerides or high fasting blood glucose, and a 32-percent higher risk of low HDL levels.
The study also compared participants who drank more than one diet or regular soda daily to those who drank less than one soft drink per week. Those who drank more than one soda a day had a 50 to 60 percent increased risk for developing new-onset metabolic syndrome.
Soda consumption has increased three-fold since the mid-1970s, according to Vasan, and questions about its link to childhood obesity and diabetes made it a natural study choice.
``We cannot say it's a solid fact that not drinking soda will reduce your risk - we cannot draw that conclusion,'' Vasan said. ``This is a choice that people have to make for themselves.''
Contact Jennifer Lord of The MetroWest Daily News (Framingham, Mass.) at 508-626-3880 or firstname.lastname@example.org.