Diet soda intake and risk of incident metabolic syndrome and type 2 diabetes in the Multi-Ethnic Study of Atherosclerosis (MESA), by Jennifer A. Nettleton and colleagues. Diabetes Care 32:726–688–694, 2009
What is the problem and what is known about it so far?
Most people think of diet soda as being harmless because it does not add calories or nutrients to the diet. However, drinking diet sodas has been linked to developing metabolic syndrome, a group of risk factors for diabetes and heart disease including high blood pressure, blood fat (cholesterol) problems, and higher than normal blood glucose levels. Some people believe this link must be related to other unknown factors, such as diet, exercise, or personal characteristics. And some have speculated that the non-sugar sweeteners in diet soda may actually cause people to want more high-calorie foods or hinder their ability to estimate how many calories they need throughout the day. For now, no one really understands the relationship between drinking diet sodas and developing metabolic syndrome.
Why did the researchers do this particular study?
The researchers wanted to learn more about the relationship between drinking diet sodas and the risk factors for diabetes and heart disease.
Who was studied?
The study included more than 6,800 adults of diverse ethnic backgrounds who were participating in a heart disease study.
How was the study done?
The researchers asked patients how often they drank diet sodas at the beginning of the study and asked questions and conducted lab tests at three follow-up periods over the next 5 years to see which patients developed diabetes or metabolic syndrome. They conducted statistical tests to find links between diet soda drinking and risk factors.
What did the researchers find?
People who drank diet soda at least once a day had a 36% greater chance of having a high waist measurement and high blood glucose levels, both of which are features of metabolic syndrome. People who drank diet soda at least once a day also had a 67% higher chance of getting diabetes compared to those who did not drink diet sodas, and this was not related to body fat measurements.
What were the limitations of the study?
People who drink diet soda may have other diet and lifestyle behaviors that would affect their development of diabetes and metabolic syndrome, and this study was not designed to take those into consideration. Information about how often participants drank diet soda was self-reported and may not have been accurate. Also, the question asked about diet sodas was combined with a question about unsweetened mineral water, which may have confused some participants.
What are the implications of the study?
Although the causes are not yet known, drinking diet soda daily may lead to weight gain, problems processing glucose in the body, and eventual diabetes.
Published by the American Diabetes Assn.