An analysis of 10 years of data from the Framingham Heart Study, a project of the National Heart, Lung and Blood Institute and Boston University, reveals that middle-aged participants who drank one or more sodas daily — regular or diet — were twice as likely as non-soda drinkers to develop a set of risk factors for heart disease and type 2 diabetes.
Known as metabolic syndrome, the risk factors include abdominal obesity and high levels of blood sugar and LDL, or “bad,” cholesterol.
So should diet soda fans can their beverage of choice?
The Blame Game
The study’s senior author, Ramachandran Vasan, MD, cautions against overreaction. The findings don’t suggest soda directly causes metabolic syndrome. The study of close to 3,500 people, published in the journal Circulation in July 2007, indicates an association between the two, a link that may say more about people who drink soda than the soda itself.
In the study, people who drank more diet and regular soda had a greater intake of fat and sugar, and less intake of fiber in their diets, says Dr. Vasan. This finding squares with other studies. “Soda drinkers may also have a more sedentary lifestyle,” Dr. Vasan adds. Soda drinkers also may have a sweeter tooth than their non-soda-drinking brethren, says Cindy Moore, MS, RD, Director of Nutrition Therapy at Cleveland Clinic. She draws an analogy to people who consume a lot of salt.
“People can get so accustomed to food with high salt content that they think anything less salty tastes bland. The same can happen with sweets, where you need higher and higher sweetness levels.” And while your soda may be artificially sweetened, the cake and candy you eat isn’t, helping to explain the higher rates of metabolic syndrome among soda drinkers, she offers.
Then there’s the rationalization that diet soda drinking “allows” you to eat higher-calorie foods — an approach bound to backfire, says Ms. Moore. Other theories pin more blame on diet soda itself. One intriguing possibility is that the caramel content in colas could promote insulin resistance, potentially leading to the dangerously high blood sugar levels of type 2 diabetes and metabolic syndrome. Research indicates an association between insulin resistance and caramel additives, but the link has yet to be confirmed in people.
The Choice is Yours
Regardless of this latest study, a sure weight-gain culprit is sugary soda. “If you need to control your blood sugar levels or a weight, choosing diet soda over regular soda is definitely way to go,” says Mario Skugor, a Cleveland Clinic endocrinologist.
However, everyone can benefit from drinking healthier alternatives, says Ms. Moore. She suggests reaching for nutrient-packed skim milk, or tea and coffee (without the cream and sugar), both low in calories and high in antioxidants.
Better yet, she says, “Why not pick water? It has no artificial sweeteners or additives, no calories, and costs next to nothing.