As Americans gain more weight at even younger ages, the search for a dietary culprit intensifies. Although noncaloric diet sodas may seem to be a safe choice when you're trying to lose or maintain weight, several studies, including one published by the American Heart Association, have shown a correlation between diet soft drink consumption and obesity or factors that lead to obesity, such as metabolic syndrome. The question of whether diet drinks cause an insulin rise similar to that seen when you consume sugar is still under hot debate as of the time of publication.
Insulin Release
When you eat a food containing carbohydrate, glucose enters your bloodstream. In response to glucose, your pancreas releases insulin, which helps cells absorb the glucose. Some people develop high insulin levels when the pancreas releases too much insulin in response to glucose. High insulin levels can lead to Type 2 diabetes or to metabolic syndrome, which includes obesity, high blood pressure, and elevated lipid, insulin and blood glucose levels. Since diet soda contains no glucose, it should not trigger an insulin release.
Studies Showing No Effect
Researchers from University Medical Center Utrecht in the Netherlands who compared glucose and insulin responses to water, artificial sugar, glucose and maltodextrin found that water and artificial sugar did not trigger either an insulin or glucose response after ingestion. Aspartame did not trigger any insulin response, according to the study, published in the November 2005 issue of the "American Journal of Clinical Nutrition."
Study Comparing Water and Diet
A study conducted by researchers from the National Institutes of Health and reported in the December 2009 issue of "Diabetes Care" examined the effects of diet soda and carbonated water on glucose and insulin. Healthy subjects drank 8 oz. of either diet soda or carbonated water 10 minutes before ingesting a 75 g glucose load. Blood levels showed a rise in insulin levels higher in subjects who drank diet soda before the glucose load than in those who drank carbonated water. However, the rise was not clinically significant, according to researchers. Glucose levels were similar in both groups. However, glucagon-like peptide-1 levels did rise significantly higher in subjects who drank diet soda, possibly because of stimulation of sweet-taste receptors, researchers theorized. Glucagon-like peptide-1 tells the brain it's full and also stimulates insulin release from the pancreas.
Study on Metabolic Syndrome
Metabolic syndrome increases the risk of heart disease and diabetes. A study published in the July 2007 issue of "Circulation," the magazine of the American Heart Association, examined the connection between soda consumption and development of metabolic syndrome. The study showed that people who drank one or more regular or diet sodas per day had a more than 50 percent higher risk of developing metabolic syndrome than those who drank less than one soda per week. This study did not prove that diet soda increases insulin levels, although insulin resistance, which often develops in conjunction with high insulin levels, often leads to metabolic syndrome.
References
- National Institute of Diabetes and Digestive and Kidney Diseases; Insulin Resistance and Pre-Diabetes; October 2008
- "Diabetes Care"; Ingestion of Diet Soda Before a Glucose Load Augments Glucagon-Like Peptide-1 Secretion; R. Brown, et al.; December 2009
- "American Journal of Clinical Nutrition"; Functional Magnetic Resonance Imaging of Human Hypothalamic Responses to Sweet Taste and Calories; P. Smeets, et al.; November 2005
- Mosby's Medical Dictionary; Glucagon-Like Peptide 1; 2009
- "Circulation"; Soft Drink Consumption and Risk of Developing Cardiometabolic Risk Factors and the Metabolic Syndrome in Middle-Aged Adults in the Community; R. Dhingra, et al.; July 2007
