The study presented by Brian Hoffmann, George Ronan, and Dhanush Haspula from the Medical College of Wisconsin suggested that things may not be that sweet for artificial sweeteners. They did a combination of in vitro (which essential means inside a test tube or similar equipment) and in vivo (meaning in a live animal) experiments using rats that were specially designed to be more susceptible to developing diabetes. For the in vitro experiments, the research team placed cells from the inside lining of the rats' small blood vessels into test tubes and exposed these cells to either sugar or a common artificial sweetener. Why the inside lining of blood vessels? Well, one of the effects of diabetes is to cause damage to small blood vessels, which then results in many of the complications of diabetes such as loss of eyesight, kidney function, and blood circulation to various parts of the body.
The in vitro experiments found that both sugars and artificial sweeteners interfered with glycosylation, a key step in which sugars are added to proteins that then affects how the proteins function. Therefore, messing up glycosylation could affect a number of functions that various proteins perform in the cells. The research team did find that sugar and artificial sweeteners seemed to affect the expression different genes differently, which implies that the way that they affect glycosylation may be different. Nonetheless, the fact that both disrupt this key biochemical process raises concerns. The second in vivo part of the study involved dividing rats into separate groups and feeding each group high doses of either a sugar (glucose or fructose) or an artificial sweetener (aspartame or acesulfame potassium) for 3 weeks. They then took blood samples from the rats and found that both sugar and artificial sweeteners affected the concentrations of fat, amino acids, and other biochemicals in their blood. In other words, in just 3 weeks, both sugar and artificial sweeteners seemed to be disrupting the way fats and proteins were being processed.
In a press release, Hoffmann said, "Despite the addition of these non-caloric artificial sweeteners to our everyday diets, there has still been a drastic rise in obesity and diabetes. In our studies, both sugar and artificial sweeteners seem to exhibit negative effects linked to obesity and diabetes, albeit through very different mechanisms from each other."