Do artificial sweeteners lead to weight gain?

Nature has challenged some of the conventional wisdom about artificial sweeteners, suggesting that blood sugar levels actually rise in animals and humans with consumption of artificial sweeteners. Now, before we get too far ahead of ourselves, let’s keep in mind that this is one of a great number of studies on this subject, and results to date have been conflicting. Nonetheless this one appears to be well designed and worthy of some special attention. Even more important to remember before we abandon our eating practices is that what we do know about eating sweets remains true: namely, that increased consumption of sugar, high fructose corn syrup, and carbohydrate calories generally, is linked to rising blood sugar and obesity. The real question here is whether artificial sweeteners, and which ones specifically, may be a better substitute. Because there’s no doubt that we are eating far too much sugar and carbohydrates generally. An American Journal of Clinical Nutrition study published in 2012 examined 40,389 healthy men and concluded that sugar sweetened beverage consumption is associated with a significantly elevated risk of type two diabetes. And what about artificial sweeteners in those beverages? The type two diabetes risk was “largely explained by health status, pre-enrollment weight change, dieting, and body mass index” meaning that once all of the appropriate variables were taken into account, the multivariate analysis showed no increased risk of type two diabetes among people who drink artificially sweetened beverages. Okay, so what does the new Nature study show? When mice were given drinking water supplemented with artificial sweeteners (saccharin, sucralose, and aspartame), they developed glucose intolerance, when compared to mice drinking water alone, or even water with sugar in it. This finding was true in mice fed regular diets and high-fat diets. The most interesting part was that when antibiotics were used to eliminate intestinal bacteria, the glucose intolerance was restored to normal. The findings indicate that the artificial sweeteners lead to changes in the gut bacteria which produced glucose intolerance. The same sort of findings occurred with four out of seven human volunteers who were given artificial sweeteners. Taken globally, this study and many others show an intriguing relationship between the bacteria that live in our gut, and important metabolic conditions such as glucose intolerance and diabetes. We are, unfortunately, quite some distance away from understanding these phenomena more fully in humans. The study has a great number of weaknesses, not the least of which is that it was performed in mice which often have metabolic regulatory systems that do not translate well to human conclusions. Another important feature of the study was that it did not involve testing all of the sweeteners available, nor did it test each of them independently. From a personal point of view, I was disappointed that the study did not include Stevia, the plant-derived sweetener used in iMetabolic protein shakes and many other products. Perhaps even worse, however, is that the researchers combined the data involving their three chosen artificial sweeteners, muddling the findings which may relate to one or two of these molecules only. So where do we go from here? Well, I certainly would not ditch your diet drinks yet, and definitely I would not encourage consuming sugar sweetened beverages or beverages sweetened with high fructose corn syrup. Those are already proven to be bad. We do need a lot more investigation of the role of gut bacteria on glucose tolerance in humans, and this latest study may provide an impetus for some good scholarship in that area as it relates to individual sweeteners and human metabolism. Kent Sasse, M.D., MPH, FACS, FACRS Minimally Invasive Solutions]]>