A large French study published last January finds a very strong association between consumption of artificially sweetened beverages and type 2 diabetes.* Could diet drinks sweetened with products such as aspartame be increasing people’s risk of diabetes? These French researchers think it’s a real possibility.
They followed 66,118 women for 14 years. It turns out that people drinking more than 12 ounces per week of sugar-sweetened beverages are at a 35% greater risk for diabetes, but people drinking more than 19 ounces per week of diet beverages have a 121% greater risk of diabetes. This association is true even after statistically controlling for other known risk factors such as weight gain, obesity, metabolic syndrome, hypertriglyceridemia, coronary artery disease, and high blood pressure.
How could artificially sweetened beverages cause diabetes? One theory is insulin spikes. When people consume sugary drinks, the sugar causes the body to spike its production of insulin, and this is thought to lead to insulin resistance over time. A study that came out in 2010 found that aspartame generates a similar body response in terms of the insulin spike. In that study, stevia (herbs with natural sweeteners) did not cause that insulin spike.
The data on this subject might still be considered conflicting. There are six similar studies that we know of, and some did not find a strong correlation between diet drinks and diabetes after statistically controlling for obesity. There is other evidence that artificially sweetened beverages may cause obesity. There is even a conflicting study that did not find aspartame to create the same insulin spikes as sugar. The fact of the matter is that there is serious evidence that artificially sweetened beverages may not be the healthy alternatives their marketing would imply. To prove this one way or the other, the scientific literature needs a randomized, controlled study.
Interestingly, in the current study, fruit juice did not correlate with an increased risk of diabetes after controlling for obesity. Two previous studies suggest that fruit juice could cause diabetes. One important difference in the current study is that they limited the fruit juice surveillance to only fresh squeezed, pure, or non-sweetened juice. This suggests that certain juices may have advantages as alternative sweet drinks.
*Fagherazzi G, Vilier A, Sartorelli D, et al. Consumption of artificially and sugar-sweetened beverages and incident type 2 diabetes in the . . . Am J Clin Nutr. Doi: 10.3945/ajcn.112.050997.