Oral and Post‐Oral Actions of Low‐Calorie Sweeteners: A Tale of Contradictions and Controversies

Abstract

Objective: Many scientists and laypeople alike have concerns about low‐calorie sweeteners (LCSs). These concerns stem from both a dissatisfaction with the taste of LCSs and reports that they cause metabolic disruptions (e.g., weight gain, glucose intolerance). Methods: This article provides a critical review of the literature on LCSs from the standpoint of their taste, gastrointestinal, and metabolic effects; biological fate in the body; and impact on ingestion and glucose homeostasis. Results and Conclusions: Mammals can readily discriminate between LCSs and sugars because both types of sweetener activate distinct oral and post‐oral sensory pathways. LCSs differ in their ability to access post‐oral tissues, but few studies have incorporated this observation into their design. It is difficult to extrapolate results between mice, rats, and humans because of interspecies differences in the taste and post‐oral actions of LCSs and the fact that investigators often use different response measures in rodents and humans. There is confounding in the experimental design of some of the most widely cited studies of LCS‐induced metabolic disruptions. The uncritical acceptance of these studies has generated considerable controversy. More work is needed to obtain a clearer understanding of the metabolic effects of LCSs.

Sodium‐glucose cotransporter 1 as a sugar taste sensor in mouse tongue

“…It was observed that non‐caloric sweeteners are fully cross‐adapted by sugars, but sugars are only partially cross‐adapted by non‐caloric sweeteners, indicating the existence of a T1R‐independent receptor site (or sites) that mediates the perception of sugar sweetness. Concerning taste intensity, although non‐caloric sweeteners evoke a sweet taste at lower concentrations than sugars, indicating a higher affinity of non‐caloric sweeteners for T1Rs than that of sugars for T1Rs or SGLTs, artificial sweeteners reportedly have a tendency to elicit a lower maximal sweet taste intensity than sugars in human, 35,36 and to elicit a lower rate of licking in rodents 37 …”

A Comparison of Psychophysical Dose-Response Behaviour across 16 Sweeteners

“…Sweetness intensity is associated with liking and reducing sucrose can negatively impact the hedonic appeal of a product and consumer acceptance of reformulated products, thereby limiting the widespread reduction of sucrose to achieve these public health goals. Non-nutritive sweeteners can be used to maintain product sweetness, while reducing the negative health impact of excessive sucrose intake, including increased body weight and risk of type-2 diabetes and cardiovascular diseases [ 6 , 7 , 8 ]. Sweet taste intensity has been shown to be associated with sucrose content of a product, but not with its energy content [ 9 , 10 ] thus creating an opportunity to reduce energy whilst matching sweet taste intensity and liking through the use of lower calorie sweeteners.…”

“…Synthetic non-nutritive sweeteners like aspartame and sucralose are still the most widely consumed due to their low cost, quality of their sweet taste and calorie-free advantage, although their long-term metabolic impacts are still being investigated [ 8 ]. In addition to reduced sucrose and calories, in recent years there has been a rise in consumer demand for ‘natural’ and clean-label ingredients [ 11 ].…”

Perspective: Standards for Research and Reporting on Low-Energy (“Artificial”) Sweeteners

“…A recent expert stakeholder panel proposed a number of research priorities for LES and health outcomes (11). While that panel did not specifically address issues relating to the execution of research and reporting on LES, others have highlighted issues in experimental design and interpretation that can magnify apparent inconsistencies in the evidence base (12)(13)(14). In this commentary, we highlight specific practices which can be considered as part of guidance to improve the design, reporting and interpretation of research on LES.…”