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Shum and Georgia’s “Review” Is More of An Opinion ‎

June 8, 2021

Shum B, Georgia S. The Effects of Non-Nutritive Sweetener Consumption in the Pediatric Populations: What We Know, What We Don’t, and What We Need to Learn. Front Endocrinol (Lausanne). 2021 Apr 1;12:625415. doi: 10.3389/fendo.2021.625415.

This paper purports to assess, in part, the effects of low-and-no-calorie sweeteners (LNCS) on the weight, caloric intake, gut microbiota, and glucose homeostasis of children.  While labeled as a “mini review” by the journal’s editors, I would refine that classification as a limited and hand-picked review. The authors seem to ignore and/or downplay the plethora of studies showing positive outcomes from a judicious use of LNCS.  Moreover, they seem to start out with an ideology and an agenda, as evidenced by this statement in the Introduction:

“This review will discuss the physiological mechanisms that contribute to the negative metabolic effects of non-nutritive sweeteners (NNS)…We will focus on how NNS alters the sweet perception leading to increase caloric consumption, how NNS alters the gut microbiota, and how disrupting metabolism and glucose homeostasis can cause pancreatic endocrine dysfunction.”

This unjustified assumption of negative outcomes from the outset raises a red flag. As a result, this “mini review”, can no longer be considered an objective one.  Rather than consider the totality of credible science, the authors tended to reference studies that fit their agenda.

Also in the Introduction, the authors stated, “NNS that were once considered inert, like saccharin, have been reported to have negative metabolic effects in observational studies, including increasing weight gain, adiposity, and risk of developing T2DM.  This is a misinterpretation, as it implies cause-and-effect, which observational studies are not capable of doing.  Observational studies on ANY food or ingredient will likely produce a statistical event, showing an “association,” and serve merely to generate a hypothesis and nothing more. 

The authors suggestion that the benefits of weight reduction may or may not outweigh “the potential negative health outcomes including type 2 diabetes, nonalcoholic fatty liver disease, and metabolic syndrome” is troubling.  As a clinician, sound weight reduction is strongly recommended for overweight and obese persons with these chronic conditions.  As for “potential negative health outcomes”, one of their referenced reviews (Lohner, et al.) noted, “no conclusive evidence for beneficial and harmful effects on those outcomes.”

The research of Susan Swithers and colleagues was often cited in this review, though this research focuses on rats, not humans, used samples too small for clinically meaningful results and lasted only five weeks. Subsequent research by this investigator has continued to be criticized for poor methodology, small numbers of animals, and even “data dredging”. 

More objective research, such as one by Piernas et al, as part of the CHOICE study, demonstrated strong credibility, yet was not referenced at all.  Piernas, et al looked at the substitution of sugar-sweetened beverages with similar beverages sweetened with LNCS and found that use of the LNCS-sweetened beverages resulted in weight loss, as well as a reduced intake of desserts.  Moreover, the study design included humans, a more appropriate sample size and followed the groups for 6 months. While it could be argued that the Piernas study did not look at children specifically, with the exception of the acknowledgement of three randomized, controlled studies that found “reduced weight gain when ‎regular soda is replaced with NNS soda in children and adolescents”‎, neither did the studies cited by Shum and Georgia.  Unfortunately, the authors devoted more space to poorly-designed animal studies. 

Regarding the purported impact of LNCS on the gut microbiota, the author began with a discussion of the differences between the microbiota of obese and normal weight persons, without a mention of LNCS.  They continue to cite animal studies, including those criticized for flawed methodology and misleading presentation of data, and do not acknowledge a plausible mechanism for any reported changes. To date, such a mechanism for how LNCS would negatively alter the gut microflora does not exist.  Some sweeteners, such as sucralose, as well as the metabolites of aspartame (aspartic acid and phenylalanine) either never reach the colon or are excreted intact. This means they cannot act as a substrate for gut bacteria.  Others, such as Stevia, have shown a mild, but positive, impact on the gut microbiota, increasing levels of good bacteria.  Still others, such as saccharin, have been shown to alter the gut microbiota when given at doses that are irrelevant to humans.

Lastly, Shum and Georgia cited research showing that gut bacterial diversity varied between consumers and non-consumers of LNCS.  Not only did this small study fail to address variations in dietary intake, the authors themselves concluded, “there are no notable differences in microbiome profiles or predicted functional capacity, but there may be differences in overall bacterial diversity.”  Further, a 2019 review of these same studies conducted by Lobach et al yet concluded, “changes in the diet unrelated to LNCS consumption are likely the major determinants of change in gut microbiota numbers and phyla, confirming the viewpoint supported by all the major international food safety and health regulatory authorities that LNCS are safe at currently approved levels.”

Bottom line: This “review” strains credibility and ignores the decades of sound evidence for judicious use of LNCS to help manage weight, diabetes, and overall reduction of sugar intake.

Keith Ayoob, EdD, RDN, FADN, is an Associate Clinical Professor Emeritus at the Albert Einstein College of Medicine. As a pediatric nutritionist and registered dietitian, Dr. Ayoob is also a past national spokesperson for the Academy of Nutrition and Dietetics. Dr. Ayoob is a consultant with the Calorie Control Council Advisory Board and the Global Stevia Institute (GSI), GSI is supported by PureCircle Ltd, a global leader in purified stevia leaf extract production.

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