Diet Soft Drinks and Women's Hearts
Those who consumed the most had highest risk, but the study results are preliminary
The study authors and beverage industry representatives point out that the study has some significant limitations. Because it only followed women over time, asking about habits and patterns that were already in place, it can't prove that diet drinks caused their heart problems.
"The women who had the greatest risk of cardiovascular effects consumed two or more diet beverages per day," the American Beverage Association said in a statement prepared in response to the study. "However, they also had higher incidence of smoking, diabetes, hypertension and overweight -- all known risk factors for heart disease. Thus, it is impossible to attribute their cardiovascular health issues to their diet beverage intake."
The researchers said they adjusted their numbers to try to account for those differences, as well as other relevant factors such as exercise and caloric intake.
Still, an expert said this one study isn't a reason to give up a favorite low-calorie drink.
"I don't think these findings in and of themselves are grounds for changing any habits right now," said study author Dr. Ankur Vyas, a cardiovascular disease fellow at the University of Iowa Hospitals and Clinics. "A lot more work needs to be done."
Still, Swithers said her studies have pointed to a couple ways diet drinks might lead to heart problems. She said animals that eat regular sugar after consuming a diet heavy in artificial sweeteners have a disrupted response to the real thing.
"[Like diabetics], they become hyperglycemic," she said. "Their blood sugars go up higher than they should."
They also make less of a heart-protective protein, she said.
"If drinking diet soda interferes with this system, then over the long term you're taking something away that protects your cardiovascular health, and that could be what's contributing to these effects," Swithers said.
Data for the study came from the U.S. government-funded Women's Health Initiative Observational Study.
Results presented at medical meetings are considered preliminary until they are scrutinized by outside experts for publication in a medical journal.