The Food Journal and Food, Nutrition & Science

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What Should I Do About Artificial Sweeteners?

What Should I Do About Artificial Sweeteners?

Dietitian Dialogues

October 29, 2014

by Debbie Fetter, Department of Nutrition, UC Davis

A recent study published by Suez and colleagues titled, “Artificial sweeteners induce glucose intolerance by altering the gut microbiota” has taken the media world by storm. Suez and colleagues investigated how non-calorie artificial sweeteners (NAS) impact the gut microbiota and the subsequent effects on glucose metabolism. What they found was a bit unnerving, but don’t jump to conclusions just yet. Let’s take a step back and discuss some background on NAS.

People like sweetness, but don’t necessarily like the high calorie load that usually comes along with sweet-tasting foods. Enter: NAS – designed to bring the enjoyment of that sweet-taste without the calorie bomb. Since most NAS pass through the gastrointestinal tract without being digested, many NAS directly interact with the intestinal microbiota (i.e. the bacteria living in the intestine). The microbiota has become a hot research topic due to its important roles in regulating many physiological processes (3). Previous research has suggested diet affects the makeup of the microbiota, along with its function (2, 5, 6, 7, 8, 10). 

Suez and colleagues used lean and obese mouse models to examine the effects NAS have on glucose regulation. The researchers found the NAS-consuming mice developed noticeable glucose intolerance (i.e. high blood glucose levels) when compared to the controls. The glucose intolerance was especially seen in the saccharin-consuming mice. Next, the researchers administered an antibiotics regimen to the lean and obese mouse groups consuming NAS. This was done to determine if the microbiota had a role in the observed glucose intolerance. After four weeks, the changes in glucose intolerance between NAS-consuming mice and the controls were gone. The authors suggest that one explanation for this is that the microbiota may regulate the NAS-induced glucose intolerance. Fecal transplantation experiments followed, which is when the stool from one organism is transferred to another. The stool from the saccharin-consuming mice was transferred to germ-free mice (i.e. mice with no microorganisms). The researchers found the fecal transplantation also transferred the glucose intolerance. This result was seen again with in vitro stool cultured with saccharin. Taken together, these results suggest saccharin may cause microbial imbalance, resulting in glucose intolerance. 

The researchers used data from an ongoing clinical nutritional study and found long-term NAS consumption was positively associated with multiple metabolic-syndrome-related clinical features, including glucose intolerance (4). Suez and colleagues recruited a small sample of seven healthy subjects, who do not usually consume NAS, and studied them for one week. On days 2 through 7, the subjects consumed the FDA’s maximal acceptable daily intake of saccharin. This value is 5 mg of saccharin per kg of bodyweight, which is equivalent to a 60 kg person consuming about three 12-fl oz. cans of Tab (11). Four out of seven of the subjects developed significantly poorer glycemic responses. These four were termed “NAS responders” and the three subjects, who did not exhibit any change, were termed “NAS non-responders.” The stool from the subjects was transferred into germ-free mice. The mice given NAS responder stool displayed significant glucose intolerance, whereas the mice given NAS non-responder stool had normal glucose tolerance.

Collectively, these results suggest that NAS consumption, in both mice and humans, may increase the risk of glucose intolerance by changing the composition and function of the microbiota. Moreover, humans may have a personalized response to NAS, which may be due to differences in the microbiota. However, this study used an extremely small human sample and more research needs to be done with a larger human sample before establishing concrete conclusions. Non-calorie artificial sweeteners (NAS) are regulated by the FDA and are considered generally recognized as safe (GRAS) (1). Qualified experts by training and experience evaluate the safety of food additives and determine if the substance is GRAS (1). Saccharin is the oldest NAS to be approved for food and beverage use (1). The current position of the Academy of Nutrition and Dietetics is NAS can be safely enjoyed when consumed within an eating plan that is aligned with current federal nutrition recommendations, as well as personal health goals and preferences (1). The takeaway here is you do not need to necessarily remove all NAS from your diet. Should you choose to enjoy products with NAS, do so in moderation. 


Debbie Fetter, Doctoral Student, University of California, Davis, received a Bachelor of Science in Nutrition Science, Cum Laude, from the University of California, Davis in 2012 and is currently pursuing a PhD in Nutrition Biology. Her research interests include nutrition education and utilizing social media to help promote longevity of healthy eating habits and behaviors. She aspires to use her love for writing and scientific background to develop nutrition education materials to teach people about nutrition. 



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