Waistlines in people, glucose levels in mice hint at sweeteners' effects
In the constant battle to lose inches or at least stay the same, we reach for the diet soda. Two studies presented June 25 and 27 at the American Diabetes Association's Scientific Sessions in San Diego suggest this might be self-defeating behavior.
Epidemiologists from the School of Medicine at The University of Texas Health Science Center San Antonio reported data showing that diet soft drink consumption is associated with increased waist circumference in humans, and a second study that found aspartame raised fasting glucose (blood sugar) in diabetes-prone mice.
"Data from this and other prospective studies suggest that the promotion of diet sodas and artificial sweeteners as healthy alternatives may be ill-advised," said Helen P. Hazuda, Ph.D., professor and chief of the Division of Clinical Epidemiology in the School of Medicine. "They may be free of calories but not of consequences."
Human study: The San Antonio Longitudinal Study of Aging
To examine the relationship between diet soft drink consumption and long-term change in waist circumference, the Health Science Center team assessed data from 474 participants in the San Antonio Longitudinal Study of Aging, or SALSA. This is a large, population-based study of the disablement process in elderly Mexican Americans and European Americans. Dr. Hazuda, senior author of the presentation, is SALSA's principal investigator and has led the study for two decades.
Measures of height, weight, waist circumference and diet soda intake were recorded at SALSA enrollment and at three follow-up exams that took place over the next decade. The average follow-up time was 9.5 years. The researchers compared long-term change in waist circumference for diet soda users versus non-users in all follow-up periods. The results were adjusted for waist circumference, diabetes status, leisure-time physical activity level, neighborhood of residence, age and smoking status at the beginning of each interval, as well as sex, ethnicity and years of education.
Diet soft drink users, as a group, experienced 70 percent greater increases in waist circumference compared with non-users. Frequent users, who said they consumed two or more diet sodas a day, experienced waist circumference increases that were 500 percent greater than those of non-users.
Abdominal fat is a major risk factor for diabetes, cardiovascular disease, cancer and other chronic conditions. "These results suggest that, amidst the national drive to reduce consumption of sugar-sweetened drinks, policies that would promote the consumption of diet soft drinks may have unintended deleterious effects," the authors wrote.
Co-authors include Sharon P. Fowler, M.P.H., faculty associate, and Ken Williams, M.S., P.Stat., adjunct assistant professor and biostatistician, in the Division of Clinical Epidemiology.
Mouse study: Aspartame consumption in diabetes-prone mice