From the desk of: Karen D. Corbin, Ph.D., R.D.
As a registered dietitian, I am often asked: “What do you think about artificial sweeteners?” My answer is always the same: “Since they are artificial and not enough research has been conducted to know for certain if they can be harmful, I suggest using them in moderation, learning to drink beverages that are naturally sugar-free, or using regular sugar instead but in moderation.” New research published in the journal Nature indicates a negative impact of artificial sweeteners on the helpful bacteria that live in our intestines. The findings were intriguing and provide one important piece of the puzzle to help better understand the role of these food additives on health.
THE STUDY
Artificial sweeteners have been shown to have beneficial effects on weight and metabolism, while other studies have shown the opposite. Despite this controversy, the Food and Drug Administration has approved six different artificial sweeteners for use in the United States. Most artificial sweeteners pass through the intestinal tract without being digested, making them available for processing by the bacteria that reside normally in the gut. These bacteria are very important for processing nutrients and can affect our metabolism and health.
A group of scientists at the Weizmann Institute of Science in Israel wanted to find out if artificial sweeteners affect the types of bacteria in the gut and, if so, what the impact is on metabolism. In mice, the scientists found that artificial sweeteners lead to insulin resistance and an imbalance of bacteria in the gut (dysbiosis), compared to water alone or water with natural sugars like glucose or sucrose. When gut bacteria from mice fed artificial sweeteners were transferred to mice that had no bacteria in their gut, the same harmful metabolic effects occurred.
WHY IS THIS IMPORTANT?
This strongly suggested that the harmful metabolic effects of artificial sweeteners were due to their effects on the gut bacteria. In non-diabetic humans, the scientists also found that long-term consumers of artificial sweeteners had many traits characteristic of metabolic syndrome and fatty liver. Importantly, when they fed healthy volunteers who did not normally consume artificial sweeteners an acceptable daily amount of artificial sweeteners for six days, their metabolisms worsened and their gut bacteria changed.
The study was well done, but focused most of its efforts on one specific artificial sweetener, so the findings may not apply equally to all of them. The part of the study where people were asked to consume artificial sweeteners was very small, and some of the people did not have the same response as others.
WHAT THIS MEANS FOR YOU
Although this study does not provide conclusive evidence that all artificial sweeteners are harmful for all people, it does suggest one way that these food additives could have negative health consequences. Moderation still stands as a reasonable course of action.
Reference: Artificial sweeteners induce glucose intolerance by altering the gut microbiota Nature. 2014 Sep 17. doi: 10.1038/nature13793. PMID: 25231862
