Hormonal responses to non-nutritive sweeteners in water and diet soda

Could Insulin Be a Better Regulator of Appetite/Satiety Balance and Body Weight Maintenance in Response to Glucose Exposure Compared to Sucrose Substitutes? Unraveling Current Knowledge and Searching for More Appropriate Choices

BACKGROUND

Insulin exerts a crucial impact on glucose control, cellular growing, function, and metabolism. It is partially modulated by nutrients, especially as a response to the intake of foods, including carbohydrates. Moreover, insulin can exert an anorexigenic effect when inserted into the hypothalamus of the brain, in which a complex network of an appetite/hunger control system occurs. The current literature review aims at thoroughly summarizing and scrutinizing whether insulin release in response to glucose exposure may be a better choice to control body weight gain and related diseases compared to the use of sucrose substitutes (SSs) in combination with a long-term, well-balanced diet.

METHODS

This is a comprehensive literature review, which was performed through searching in-depth for the most accurate scientific databases and applying effective and relevant keywords.

RESULTS

The insulin action can be inserted into the hypothalamic orexigenic/anorexigenic complex system, activating several anorexigenic peptides, increasing the hedonic aspect of food intake, and effectively controlling the human body weight. In contrast, SSs appear not to affect the orexigenic/anorexigenic complex system, resulting in more cases of uncontrolled body weight maintenance while also increasing the risk of developing related diseases.

CONCLUSIONS

Most evidence, mainly derived from in vitro and in vivo animal studies, has reinforced the insulin anorexigenic action in the hypothalamus of the brain. Simultaneously, most available clinical studies showed that SSs during a well-balanced diet either maintain or even increase body weight, which may indirectly be ascribed to the fact that they cannot cover the hedonic aspect of food intake. However, there is a strong demand for long-term longitudinal surveys to effectively specify the impact of SSs on human metabolic health.

Activation and inhibition of the sweet taste receptor TAS1R2-TAS1R3 differentially affect glucose tolerance in humans

The sweet taste receptor, TAS1R2-TAS1R3, is expressed in taste bud cells, where it conveys sweetness, and also in intestinal enteroendocrine cells, where it may facilitate glucose absorption and assimilation. In the present study, our objective was to determine whether TAS1R2-TAS1R3 influences glucose metabolism bidirectionally via hyperactivation with 5 mM sucralose (n = 12) and inhibition with 2 mM sodium lactisole (n = 10) in mixture with 75 g glucose loads during oral glucose tolerance tests (OGTTs) in healthy humans. Plasma glucose, insulin, and glucagon were measured before, during, and after OGTTs up to 120 minutes post-prandially. We also assessed individual participants' sweet taste responses to sucralose and their sensitivities to lactisole sweetness inhibition. The addition of sucralose to glucose elevated plasma insulin responses to the OGTT (F(1, 11) = 4.55, p = 0.056). Sucralose sweetness ratings were correlated with early increases in plasma glucose (R2 = 0.41, p<0.05), as well as increases in plasma insulin (R2 = 0.38, p<0.05) when sucralose was added to the OGTT (15 minute AUC). Sensitivity to lactisole sweetness inhibition was correlated with decreased plasma glucose (R2 = 0.84, p<0.01) when lactisole was added to the OGTT over the whole test (120 minute AUC). In summary, stimulation and inhibition of the TAS1R2-TAS1R3 receptor demonstrates that TAS1R2-TAS1R3 helps regulate glucose metabolism in humans and may have translational implications for metabolic disease risk.

Metabolic Effects of Selected Conventional and Alternative Sweeteners: A Narrative Review

Sugar consumption is known to be associated with a whole range of adverse health effects, including overweight status and type II diabetes mellitus. In 2015, the World Health Organization issued a guideline recommending the reduction of sugar intake. In this context, alternative sweeteners have gained interest as sugar substitutes to achieve this goal without loss of the sweet taste. This review aims to provide an overview of the scientific literature and establish a reference tool for selected conventional sweeteners (sucrose, glucose, and fructose) and alternative sweeteners (sucralose, xylitol, erythritol, and D-allulose), specifically focusing on their important metabolic effects. The results show that alternative sweeteners constitute a diverse group, and each substance exhibits one or more metabolic effects. Therefore, no sweetener can be considered to be inert. Additionally, xylitol, erythritol, and D-allulose seem promising as alternative sweeteners due to favorable metabolic outcomes. These alternative sweeteners replicate the benefits of sugars (e.g., sweetness and gastrointestinal hormone release) while circumventing the detrimental effects of these substances on human health.

Effects of Low-Calorie Sweetener Restriction on Glycemic Variability and Cardiometabolic Health in Children with Type 1 Diabetes: Findings of a Pilot and Feasibility Study

Low-calorie sweeteners (LCS) are commonly consumed by children with type 1 diabetes (T1D), yet their role in cardiometabolic health is unclear. This study examined the feasibility, acceptability, and preliminary effects of 12 weeks of LCS restriction among children with T1D. Children (n = 31) with T1D completed a two-week run-in (n = 28) and were randomly assigned to avoid LCS (LCS restriction, n = 15) or continue their usual LCS intake (n = 13). Feasibility was assessed using recruitment, retention, and adherence rates percentages. Acceptability was assessed through parents completing a qualitative interview (subset, n = 15) and a satisfaction survey at follow-up. Preliminary outcomes were between-group differences in change in average daily time-in-range (TIR) over 12 weeks (primary), and other measures of glycemic variability, lipids, inflammatory biomarkers, visceral adiposity, and dietary intake (secondary). Linear regression, unadjusted and adjusted for age, sex, race, and change in BMI, was used to compare mean changes in all outcomes between groups. LCS restriction was feasible and acceptable. No between-group differences in change in TIR or other measures of glycemic variability were observed. However, significant decreases in TNF-alpha (-0.23 ± 0.08 pg/mL) and improvements in cholesterol (-0.31 ± 0.18 mmol/L) and LDL (-0.60 ± 0.39 mmol/L) were observed with usual LCS intake, compared with LCS restriction. Those randomized to LCS restriction did not report increases in total or added sugar intake, and lower energy intake was reported in both groups (-190.8 ± 106.40 kcal LCS restriction, -245.3 ± 112.90 kcal usual LCS intake group). Decreases in percent energy from carbohydrates (-8.5 ± 2.61) and increases in percent energy from protein (3.2 ± 1.16) and fat (5.2 ± 2.02) were reported with usual LCS intake compared with LCS restriction. Twelve weeks of LCS restriction did not compromise glycemic variability or cardiometabolic outcomes in this small sample of youth with T1D. Further examination of LCS restriction among children with T1D is warranted.

The Effect of Non-Nutritive Sweetened Beverages on Postprandial Glycemic and Endocrine Responses: A Systematic Review and Network Meta-Analysis

Background: There has been an emerging concern that non-nutritive sweeteners (NNS) can increase the risk of cardiometabolic disease. Much of the attention has focused on acute metabolic and endocrine responses to NNS. To examine whether these mechanisms are operational under real-world scenarios, we conducted a systematic review and network meta-analysis of acute trials comparing the effects of non-nutritive sweetened beverages (NNS beverages) with water and sugar-sweetened beverages (SSBs) in humans. Methods: MEDLINE, EMBASE, and The Cochrane Library were searched through to January 15, 2022. We included acute, single-exposure, randomized, and non-randomized, clinical trials in humans, regardless of health status. Three patterns of intake were examined: (1) uncoupling interventions, where NNS beverages were consumed alone without added energy or nutrients; (2) coupling interventions, where NNS beverages were consumed together with added energy and nutrients as carbohydrates; and (3) delayed coupling interventions, where NNS beverages were consumed as a preload prior to added energy and nutrients as carbohydrates. The primary outcome was a 2 h incremental area under the curve (iAUC) for blood glucose concentration. Secondary outcomes included 2 h iAUC for insulin, glucagon-like peptide 1 (GLP-1), gastric inhibitory polypeptide (GIP), peptide YY (PYY), ghrelin, leptin, and glucagon concentrations. Network meta-analysis and confidence in the network meta-analysis (CINeMA) were conducted in R-studio and CINeMA, respectively. Results: Thirty-six trials involving 472 predominantly healthy participants were included. Trials examined a variety of single NNS (acesulfame potassium, aspartame, cyclamate, saccharin, stevia, and sucralose) and NNS blends (acesulfame potassium + aspartame, acesulfame potassium + sucralose, acesulfame potassium + aspartame + cyclamate, and acesulfame potassium + aspartame + sucralose), along with matched water/unsweetened controls and SSBs sweetened with various caloric sugars (glucose, sucrose, and fructose). In uncoupling interventions, NNS beverages (single or blends) had no effect on postprandial glucose, insulin, GLP-1, GIP, PYY, ghrelin, and glucagon responses similar to water controls (generally, low to moderate confidence), whereas SSBs sweetened with caloric sugars (glucose and sucrose) increased postprandial glucose, insulin, GLP-1, and GIP responses with no differences in postprandial ghrelin and glucagon responses (generally, low to moderate confidence). In coupling and delayed coupling interventions, NNS beverages had no postprandial glucose and endocrine effects similar to controls (generally, low to moderate confidence). Conclusions: The available evidence suggests that NNS beverages sweetened with single or blends of NNS have no acute metabolic and endocrine effects, similar to water. These findings provide support for NNS beverages as an alternative replacement strategy for SSBs in the acute postprandial setting.

The effect of regular consumption of four low- or no-calorie sweeteners on glycemic response in healthy women: A randomized controlled trial

OBJECTIVES

The aim of this study was to determine the effects of regular exposure to certain low- or no-calorie sweeteners (LNCS) on glucose tolerance and glucagon-like peptide 1 (GLP-1) release in healthy individuals.

METHODS

It was designed as a randomized, single-blinded, controlled study. Healthy and normoglycemic adults who did not have regular consumption of LNCS were recruited. Participants underwent a 75-g oral glucose tolerance test (OGTT) at baseline and were randomly assigned to consume 330 mL water sweetened with saccharine, sucralose, or aspartame + acesulfame-K (Asp+Ace-K), or plain water for the control group, daily for 4 wk. Fasting plasma glucose, insulin, GLP-1, and glycated hemoglobin A_1c (HbA_1c) levels and 1-h, 2-h, and 3-h plasma glucose and insulin levels during OGTT were obtained at baseline. The change in insulin sensitivity was assessed by both the Homeostatic Model Assessment Insulin Resistance (HOMA-IR) Index and the Matsuda Index. Anthropometric measurements and dietary intakes were determined at baseline. Baseline measurements were repeated at week 4.

RESULTS

Of the participants enrolled in the study, 42 (age, 21.24 ± 2.26 y; body mass index, 20.65 ± 2.88 kg/m²) completed the 4-wk intervention period. There were no differences for glucose, insulin, GLP-1, or HbA_1c levels or HOMA-IR scores at baseline or at week 4 when compared with the control group. The area under the curve of mean glucose and insulin values during OGTT were also found to be similar between groups at baseline and week 4. There were also no effects of LNCS intake on body weight, body composition, and waist circumference.

CONCLUSIONS

These results suggest that regular consumption of LNCS-sweetened water similar to doses consumed in daily life over 4 wk had no significant effect on glycemic response, insulin sensitivity, GLP-1 release, and body weight in healthy individuals. This trial was registered at www.

CLINICALTRIALS

gov as NCT04904133.

The Combined Effects of Aspartame and Acesulfame-K Blends on Appetite: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Aspartame (Asp) and acesulfame-K (Ace-K) are nonnutritive sweeteners (NNSs) commonly used in combination to replace added sugars in reduced- or low-calorie foods and beverages. Despite Asp/Ace-K blends having negligible calories, their effects on appetite have not been reviewed systematically. We therefore undertook a systematic review and meta-analysis of the metabolic effects of Asp/Ace-K blends on energy intake (EI), subjective appetite scores, blood glucose, and the incretin hormones glucose-dependent insulinotropic peptide and glucagon-like peptide. MEDLINE, Web of Science, and Cochrane CENTRAL databases (Embase, PubMed, and CINAHL) were searched (May 2021) for randomized controlled trials (RCTs). Human RCTs using Asp/Ace-K blends compared with sugar and water controls were included, whereas isolated cell and animal studies were excluded. An overall 4829 publications were identified and 8 studies, including 274 participants, were retrieved for review. The Asp/Ace-K group's EI was significantly reduced compared with sugar [mean difference (MD): -196.56 kcal/meal; 95% CI: -332.01, -61.11 kcal/meal; P = 0.004] and water (MD: -213.42 kcal/meal; 95% CI: -345.4, -81.44 kcal/meal; P = 0.002). Meta-analysis of subjective appetite scores and incretins could not be undertaken due to inconsistencies in data reporting and insufficient data, respectively, but of the 4 studies identified, no differences were observed between Asp/Ace-K blends and controls. The Asp/Ace-K group's blood glucose was nonsignificantly reduced compared with sugar (MD: -1.48 mmol/L; 95% CI: -3.26, 0.3 mmol/L; P = 0.1) and water (MD: -0.08 mmol/L; 95% CI: -0.62, 0.47 mmol/L; P = 0.78). Lower EI in participants who were predominantly healthy and assigned to Asp/Ace-K blends could not be reliably attributed to changes in subjective appetite scores. Blood glucose and incretins were also generally not affected by Asp/Ace-K blends when compared with controls. Additional short- and long-term RCTs using NNSs and sugars at dietarily relevant levels are needed. This trial was registered at the International Prospective Register of Systematic Reviews (PROSPERO: CRD42017061015).

The Effect of Artificial Sweeteners Use on Sweet Taste Perception and Weight Loss Efficacy: A Review

Excessive consumption of sugar-rich foods is currently one of the most important factors that has led to the development of the global pandemic of obesity. On the other hand, there is evidence that obesity contributes to reduced sensitivity to sweet taste and hormonal changes affecting appetite, leading to an increased craving for sweets. A high intake of sugars increases the caloric value of the diet and, consequently, leads to weight gain. Moreover, attention is drawn to the concept of the addictive properties of sugar and sugary foods. A potential method to reduce the energy value of diet while maintaining the sweet taste is using non-nutritive sweeteners (NNS). NNS are commonly used as table sugar substitutes. This wide group of chemical compounds features high sweetness almost without calories due to its high sweetening strength. NNS include aspartame, acesulfame-K, sucralose, saccharin, cyclamate, neohesperidin dihydrochalcone (neohesperidin DC), neotame, taumatin, and advantame. The available evidence suggests that replacing sugar with NNS may support weight control. However, the effect of NNS on the regulation of appetite and sweet taste perception is not clear. Therefore, the review aimed to summarize the current knowledge about the use of NNS as a potential strategy for weight loss and their impact on sweet taste perception. Most studies have demonstrated that consumption of NNS-sweetened foods does not increase sweetness preference orenergy intake. Nonetheless, further research is required to determine the long-term effects of NNS on weight management.

Rationale and design of DRINK-T1D: A randomized clinical trial of effects of low-calorie sweetener restriction in children with type 1 diabetes

BACKGROUND

Low-calorie sweeteners (LCSs) provide sweetness without sugar or calories and are used to replace added sugars by many children with type 1 diabetes (T1D). However, the role of LCSs in diabetes management and cardiometabolic health is unclear.

OBJECTIVE

The Diabetes Research in Kids Study (DRINK-T1D) aims to investigate effects of LCS restriction on glycemic variability, visceral adiposity, lipid profiles, and systemic inflammation among children 6-12 years old with T1D.

METHODS

Children with T1D, who report habitual consumption of foods and beverages containing LCSs, are recruited from the Washington Nationals Diabetes Care Complex (DCC) at Children's National Hospital (CNH) in Washington, DC. Following a phone screening and two-week run-in period involving continuation of usual LCS intake, children are randomized to 12 weeks of LCS restriction (replacement of diet beverages with still or sparkling water and avoidance of other sources of LCSs) or continued usual LCS intake (control). The primary outcome is the difference in change in glycemic variability in the LCS restriction group versus the control group. Change in glycemic variability will be assessed as the difference in daily average time-in-range (TIR), measured using continuous glucose monitoring (CGM) during two weeks at the end of the 12-week intervention, compared with during the two-week run-in period prior to randomization. Participants also complete a variety of anthropometric, metabolic, dietary, and behavioral assessments throughout the 14-week study.

CONCLUSIONS

DRINK-T1D is an innovative, randomized controlled trial, evaluating effects of LCS restriction on glycemic variability and cardiometabolic health in children with T1D. Findings of DRINK-T1D will support or challenge the common practice of recommending LCS use in this patient population and will have clinically relevant implications for pediatric T1D management.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT04385888.

Effect of sucralose and aspartame on glucose metabolism and gut hormones

Non-nutritive sweeteners are thought to be useful replacements for caloric sweeteners in sweet food and beverages, since the reduction in energy and carbohydrate intake may lead to health benefits stemming from weight management and glycemic control. However, the potential effects of non-nutritive sweeteners on glucose metabolism and gut hormones have not been determined definitively. Here, the available evidence of the effects of aspartame and sucralose consumption on glucose metabolism and gut hormones is reviewed. A majority of studies have found that consumption of aspartame or sucralose has no effect on concentrations of blood glucose, insulin, or gut hormones; however, 2 trials have shown that aspartame consumption affects glucose, insulin, and glucagon-like peptide 1 concentrations, while only a few trials have shown that sucralose consumption affects glucose, insulin, and glucagon-like peptide 1 concentrations. One study found higher glucose concentrations after sucralose consumption, while 3 studies found lower concentrations and 33 studies found no change in glucose concentrations. Moreover, only 4 studies reported increased concentrations of glucagon-like peptide 1. Three studies reported decreased insulin sensitivity following sucralose consumption, while 1 trial reported an increase in insulin sensitivity. In summary, the evidence from the clinical trials conducted to date is contradictory because of the different protocols used.

Consumption of Beverages Containing Low-Calorie Sweeteners, Diet, and Cardiometabolic Health in Youth With Type 2 Diabetes

BACKGROUND

Low-calorie sweetened beverages (LCSBs) are commonly used as a lower-calorie alternative to sugar-sweetened beverages (SSBs) by individuals with type 2 diabetes. However, little is known about how intake of LCSBs is related to dietary intake and cardiometabolic health, particularly among youth.

OBJECTIVE

To test the hypothesis that having higher baseline LCSB intake and increasing LCSB intake over 2 years of follow-up are associated with poorer dietary intake and higher cardiometabolic risk factors among youth enrolled in the Treatment Option for Type 2 Diabetes in Adolescents and Youth (TODAY) study.

DESIGN

Secondary, exploratory, analysis of baseline and longitudinal data from the TODAY study, which was a randomized, multisite trial conducted from 2004 to 2012, to compare effects of 3 interventions (metformin alone, metformin + rosiglitazone, and metformin + intensive lifestyle intervention) on glycemic control in youth with type 2 diabetes.

PARTICIPANTS/SETTING

The study included 476 children and adolescents (10-17 years, mean body mass index 34.9 ± 7.8 kg/m²), who were participants in the multicenter (n = 15) TODAY study.

MAIN OUTCOME MEASURES

Diet was assessed using a food frequency questionnaire. Differences in energy intake, macronutrients, food group intakes, and cardiometabolic biomarkers were evaluated in 3 groups of LCSB consumers at baseline (low [1-4 servings/wk], medium [5-11 servings/wk], and high [≥12 servings/wk]), each compared with nonconsumers, and between 4 groups of change in LCSB intake (nonconsumption at start of study and nonconsumption after 2 years, increase in consumption after 2 years, decrease in consumption after 2 years, and high consumption at start of study and high consumption after 2 years).

STATISTICAL ANALYSES PERFORMED

Multivariable linear regression was performed at baseline and longitudinally over 2 years of follow-up.

RESULTS

Energy (kilocalories), fiber, carbohydrate, total fat, saturated fat, and protein intake (grams) were higher among high LCSB consumers compared with nonconsumers at baseline. No associations were observed between LCSB consumption and cardiometabolic risk factors at baseline. Change in LCSB intake between baseline and follow-up was not associated with change in energy intake or cardiometabolic risk factors. Participants who decreased LCSB consumption reported greater increases in sugar intake (18.4 ± 4.8 g) compared with those who increased LCSB consumption (5.7 ± 4.9 g) or remained high LCSB consumers (5.9 ± 7.4 g), but this trend was not statistically significant after a correction for multiple testing.

CONCLUSIONS

LCSB consumption was associated with higher energy intake in youth with type 2 diabetes, with the highest energy intakes reported in high LCSB consumers. Those who reduced LCSB consumption tended to report greater increases in sugar intake during follow-up, but further studies are needed to better understand this trend.

Association of Cooking Patterns with Inflammatory and Cardio-Metabolic Risk Biomarkers

Diet has been clearly associated with cardiovascular disease, but few studies focus on the influence of cooking and food preservation methods on health. The aim of this study was to describe cooking and food preservation patterns, as well as to examine their association with inflammatory and cardio-metabolic biomarkers in the Spanish adult population. A cross-sectional study of 10,010 individuals, representative of the Spanish population, aged 18 years or over was performed using data from the ENRICA study. Food consumption data were collected through a face-to-face dietary history. Cooking and food preservation patterns were identified by factor analysis with varimax rotation. Linear regression models adjusted for main confounders were built. Four cooking and food preservation patterns were identified. The Spanish traditional pattern (positively correlated with boiling and sautéing, brining, and light frying) tends to be cardio-metabolically beneficial (with a reduction in C-reactive protein (−7.69%)), except for high density lipoprotein cholesterol (HDL-c), insulin levels, and anthropometrics. The health-conscious pattern (negatively correlated with battering, frying, and stewing) tends to improve renal function (with a reduction in urine albumin (−9.60%) and the urine albumin/creatinine ratio (−4.82%)). The youth-style pattern (positively correlated with soft drinks and distilled alcoholic drinks and negatively with raw food consumption) tends to be associated with good cardio-metabolic health except, for lower HDL-c (−6.12%), higher insulin (+6.35%), and higher urine albumin (+27.8%) levels. The social business pattern (positively correlated with the consumption of fermented alcoholic drinks, food cured with salt or smoke, and cured cheese) tends to be detrimental for the lipid profile (except HDL-c), renal function (urine albumin +8.04%), diastolic blood pressure (+2.48%), and anthropometrics. Cooking and food preservation patterns showed a relationship with inflammatory and cardio-metabolic health biomarkers. The Spanish traditional pattern and the health-conscious pattern were associated with beneficial effects on health and should be promoted. The youth-style pattern calls attention to some concerns, and the social business pattern was the most detrimental one. These findings support the influence of cooking and preservation patterns on health.

The Impact of Artificial Sweeteners on Body Weight Control and Glucose Homeostasis

A poor diet is one of the leading causes for non-communicable diseases. Due to the increasing prevalence of overweight and obesity, there is a strong focus on dietary overconsumption and energy restriction. Many strategies focus on improving energy balance to achieve successful weight loss. One of the strategies to lower energy intake is refraining from sugars and replacing them with artificial sweeteners, which maintain the palatability without ingesting calories. Nevertheless, the safety and health benefits of artificial sweeteners consumption remain a topic of debate within the scientific community and society at large. Notably, artificial sweeteners are metabolized differently from each other due to their different properties. Therefore, the difference in metabolic fate of artificial sweeteners may underlie conflicting findings that have been reported related to their effects on body weight control, glucose homeostasis, and underlying biological mechanisms. Thus, extrapolation of the metabolic effects of a single artificial sweetener to all artificial sweeteners is not appropriate. Although many rodent studies have assessed the metabolic effects of artificial sweeteners, long-term studies in humans are scarce. The majority of clinical studies performed thus far report no significant effects or beneficial effects of artificial sweeteners on body weight and glycemic control, but it should be emphasized that the study duration of most studies was limited. Clearly, further well-controlled, long-term human studies investigating the effects of different artificial sweeteners and their impact on gut microbiota, body weight regulation and glucose homeostasis, as well as the underlying mechanisms, are warranted.

A rational review on the effects of sweeteners and sweetness enhancers on appetite, food reward and metabolic/adiposity outcomes in adults

Numerous strategies have been investigated to overcome the excessive weight gain that accompanies a chronic positive energy balance. Most approaches focus on a reduction of energy intake and the improvement of lifestyle habits. The use of high intensity artificial sweeteners, also known as non-caloric sweeteners (NCS), as sugar substitutes in foods and beverages, is rapidly developing. NCS are commonly defined as molecules with a sweetness profile of 30 times higher or more that of sucrose, scarcely contributing to the individual's net energy intake as they are hardly metabolized. The purpose of this review is first, to assess the impact of NCS on eating behaviour, including subjective appetite, food intake, food reward and sensory stimulation; and secondly, to assess the metabolic impact of NCS on body weight regulation, glucose homeostasis and gut health. The evidence reviewed suggests that while some sweeteners have the potential to increase subjective appetite, these effects do not translate in changes in food intake. This is supported by a large body of empirical evidence advocating that the use of NCS facilitates weight management when used alongside other weight management strategies. On the other hand, although NCS are very unlikely to impair insulin metabolism and glycaemic control, some studies suggest that NCS could have putatively undesirable effects, through various indirect mechanisms, on body weight, glycemia, adipogenesis and the gut microbiota; however there is insufficient evidence to determine the degree of such effects. Overall, the available data suggests that NCS can be used to facilitate a reduction in dietary energy content without significant negative effects on food intake behaviour or body metabolism, which would support their potential role in the prevention of obesity as a complementary strategy to other weight management approaches. More research is needed to determine the impact of NCS on metabolic health, in particular gut microbiota.

An alternative pathway for sweet sensation: possible mechanisms and physiological relevance

Sweet substances are detected by taste-bud cells upon binding to the sweet-taste receptor, a T1R2/T1R3 heterodimeric G protein-coupled receptor. In addition, experiments with mouse models lacking the sweet-taste receptor or its downstream signaling components led to the proposal of a parallel "alternative pathway" that may serve as metabolic sensor and energy regulator. Indeed, these mice showed residual nerve responses and behavioral attraction to sugars and oligosaccharides but not to artificial sweeteners. In analogy to pancreatic β cells, such alternative mechanism, to sense glucose in sweet-sensitive taste cells, might involve glucose transporters and K_ATP channels. Their activation may induce depolarization-dependent Ca²⁺ signals and release of GLP-1, which binds to its receptors on intragemmal nerve fibers. Via unknown neuronal and/or endocrine mechanisms, this pathway may contribute to both, behavioral attraction and/or induction of cephalic-phase insulin release upon oral sweet stimulation. Here, we critically review the evidence for a parallel sweet-sensitive pathway, involved signaling mechanisms, neural processing, interactions with endocrine hormonal mechanisms, and its sensitivity to different stimuli. Finally, we propose its physiological role in detecting the energy content of food and preparing for digestion.

Effects of the Daily Consumption of Stevia on Glucose Homeostasis, Body Weight, and Energy Intake: A Randomised Open-Label 12-Week Trial in Healthy Adults

Stevia is a non-nutritive sweetener, providing sweet taste with no calories. This randomised, controlled, open-label 2-parallel arm trial examined the effects of daily stevia consumption on glycaemia in healthy adults. Secondary endpoints included body weight (BW) and energy intake (EI). Healthy participants (n = 28; aged 25 ± 5y, body mass index 21.2 ± 1.7 kg/m²) were randomised into either the stevia group (n = 14)—required to consume a stevia extract daily—or to the control group (n = 14). At weeks 0 and 12, the glucose and insulin responses to an oral glucose tolerance test were measured; BW and EI were assessed at weeks 0, 6, and 12. There was no significant difference in the glucose or insulin responses. There was a significant main effect of group on BW change (F(1,26) = 5.56, p = 0.026), as the stevia group maintained their weight as opposed to the control group (mean weight change at week 12: −0.22 kg, 95%CI [−0.96, 0.51] stevia group, +0.89 kg, 95%CI [0.16, 1.63] control group). The energy intake was significantly decreased between week 0 and 12 in the stevia group (p = 0.003), however no change was found in the control group (p = 0.973). Although not placebo-controlled, these results suggest that daily stevia consumption does not affect glycaemia in healthy individuals, but could aid in weight maintenance and the moderation of EI.

Acute glycemic and insulinemic effects of low-energy sweeteners: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

It has been suggested that low-energy sweeteners (LES) may be associated with an increased risk of metabolic diseases, possibly due to stimulation of glucose-responsive mechanisms.

OBJECTIVE

We conducted a systematic review and meta-analysis of human intervention studies examining the acute effect of LES intake on postprandial glucose (PPG) and postprandial insulin (PPI) responses, in order to comprehensively and objectively quantify these relations.

METHODS

We systematically searched the Medline, OVID FSTA, and SCOPUS databases until January 2020. Randomized controlled trials comparing acute postprandial effects on PPG and/or PPI after exposure to LES, either alone, with a meal, or with other nutrient-containing preloads to the same intervention without LES were eligible for inclusion. PPG and PPI responses were calculated as mean incremental area under the curve divided by time. Meta-analyses were performed using random effects models with inverse variance weighing.

RESULTS

Twenty-six papers (34 PPG trials and 29 PPI trials) were included. There were no reports of statistically significant differences in the effects of LES on PPG and PPI responses compared with control interventions. Pooled effects of LES intake on the mean change difference in PPG and PPI were -0.02 mmol/L (95% CI: -0.09, 0.05) and -2.39 pmol/L (95% CI: -11.83, 7.05), respectively. The results did not appreciably differ by the type or dose of LES consumed, cointervention type, or fasting glucose and insulin levels. Among patients with type 2 diabetes, the mean change difference indicated a smaller PPG response after exposure to LES compared with the control (-0.3 mmol/L; 95% CI: -0.53, -0.07).

CONCLUSIONS

Ingestion of LES, administered alone or in combination with a nutrient-containing preload, has no acute effects on the mean change in postprandial glycemic or insulinemic responses compared with a control intervention. Apart from a small beneficial effect on PPG (-0.3 mmol/L) in studies enrolling patients with type 2 diabetes, the effects did not differ by type or dose of LES, or fasting glucose or insulin levels. This review and meta-analysis was registered at PROSPERO as CRD42018099608.

Consumption of non-nutritive sweeteners during pregnancy

In an effort to reduce sugar consumption to prevent diabetes mellitus and cardiovascular diseases, "sugar-free" or "no added sugar" products that substitute sugar with non-nutritive sweeteners (NNSs) (eg, Splenda, Sweet'N Low, and Stevia) have become increasingly popular. The use of these products during pregnancy has also increased, with approximately 30% of pregnant women reporting intentional NNS consumption. In clinical studies with nonpregnant participants and animal models, NNSs were shown to alter gut hormonal secretion, glucose absorption, appetite, kidney function, in vitro insulin secretion, adipogenesis, and microbiome dysbiosis of gut bacteria. In pregnant animal models, NNS consumption has been associated with altered sweet taste preference later in life and metabolic dysregulations in the offspring (eg, elevated body mass index, increased risk of obesity, microbiome dysbiosis, and abnormal liver function tests). Despite the accumulating evidence, no specific guidelines for NNS consumption are available for pregnant women. Furthermore, there are limited clinical studies on the effects of NNS consumption during pregnancy and postpartum and long-term outcomes in the offspring.

Sucralose Consumption over 2 Weeks in Healthy Subjects Does Not Modify Fasting Plasma Concentrations of Appetite-Regulating Hormones: A Randomized Clinical Trial

BACKGROUND

The effect of nonnutritive sweeteners on appetite is controversial. Some studies have found changes in certain appetite control hormones with sucralose intake that may be through interaction with sweet taste receptors located in the intestine.

OBJECTIVE

The aim of this study was to evaluate whether sucralose consumption could produce changes in fasting plasma concentrations of appetite-regulating hormones, including glucagon-like peptide 1, ghrelin, peptide tyrosine tyrosine, and leptin, and secondarily in insulin resistance.

DESIGN

A 2-week parallel randomized clinical trial with an additional visit conducted 1 week after dosing termination.

PARTICIPANTS/SETTING

Sixty healthy, normal-weight individuals, without habitual consumption of nonnutritive sweeteners were recruited from July 2015 to March 2017 in Mexico City.

INTERVENTION

Daily sucralose consumption at 15% of the acceptable daily intake by using commercial sachets added to food. The control group followed the same protocol without an intervention.

MAIN OUTCOMES MEASURED

Fasting concentrations of appetite regulating hormones before and after the intervention. Fasting glucose and insulin concentrations were measured to assess insulin resistance as a secondary outcome.

STATISTICAL ANALYSIS PERFORMED

Basal and final concentrations were compared using Wilcoxon matched-pairs test and Mann-Whitney U test for analysis between groups. Repeated measures analysis of variance was used to evaluate changes in the homeostasis model assessment of insulin resistance.

RESULTS

Sucralose was not associated with changes in any of the hormones measured. One week postintervention, an incremental change (P=0.04) in the homeostasis model assessment of insulin resistance was found in the intervention group.

CONCLUSIONS

Sucralose intake is not associated with changes in fasting concentrations of glucagon-like peptide 1, ghrelin, peptide tyrosine tyrosine, or leptin. An increase in the homeostasis model assessment of insulin resistance observed only at 1 week postdosing is of unknown clinical significance, if any.

Effects of Non-nutritive Sweeteners on Sweet Taste Processing and Neuroendocrine Regulation of Eating Behavior

PURPOSE OF REVIEW

Non-nutritive sweeteners (NNS) are increasingly used as a replacement for nutritive sugars as means to quench the desire for "sweets" while contributing few or no dietary calories. However, there is concern that NNS may uncouple the evolved relationship between sweet taste and post-ingestive neuroendocrine signaling. In this review, we examine the effects of NNS exposure on neural and peripheral systems in humans.

RECENT FINDINGS

NNS exposure during early development may influence sweet taste preferences, and NNS consumption might increase motivation for sweet foods. Neuroimaging studies provide evidence that NNS elicit differential neuronal responsivity in areas related to reward and satiation, compared with caloric sweeteners. Findings are heterogenous regarding whether NNS affect physiological responses. Additional studies are warranted regarding the consequences of NNS on metabolic outcomes and neuroendocrine pathways. Given the widespread popularity of NNS, future studies are essential to establish their role in long-term health.

Intense Sweeteners, Taste Receptors and the Gut Microbiome: A Metabolic Health Perspective

Intense sweeteners (IS) are often marketed as a healthier alternative to sugars, with the potential to aid in combating the worldwide rise of diabetes and obesity. However, their use has been counterintuitively associated with impaired glucose homeostasis, weight gain and altered gut microbiota. The nature of these associations, and the mechanisms responsible, are yet to be fully elucidated. Differences in their interaction with taste receptors may be a potential explanatory factor. Like sugars, IS stimulate sweet taste receptors, but due to their diverse structures, some are also able to stimulate bitter taste receptors. These receptors are expressed in the oral cavity and extra-orally, including throughout the gastrointestinal tract. They are involved in the modulation of appetite, glucose homeostasis and gut motility. Therefore, taste genotypes resulting in functional receptor changes and altered receptor expression levels may be associated with metabolic conditions. IS and taste receptors may both interact with the gastrointestinal microbiome, and their interactions may potentially explain the relationship between IS use, obesity and metabolic outcomes. While these elements are often studied in isolation, the potential interactions remain unexplored. Here, the current evidence of the relationship between IS use, obesity and metabolic outcomes is presented, and the potential roles for interactions with taste receptors and the gastrointestinal microbiota in modulating these relationships are explored.

[The controversial effects of low-calorie sweeteners]

Substantial reviews of the most recent evidence report a strong relationship between the consumption of sugar-sweetened beverages and adverse health effects, such as the prevalence of obesity and metabolic diseases. Various public policies were recently undertaken by many countries in the hope of reducing sugar-sweetened beverage consumption amongst their population. This has led the food industries to promote low-calorie sweeteners (sugar substitutes) as a healthy alternative that would limit caloric intake without compromising the sweet taste of food and beverages. However, is the use of low-calorie sweeteners as a means of limiting or reducing energy intake without consequences for our health? This review aims to discuss the effects of low-calorie sweeteners consumption on health and to elucidate whether their use should be recommended by health professionals to their patients as part of weight management.

Consumption of Diet Soda Sweetened with Sucralose and Acesulfame-Potassium Alters Inflammatory Transcriptome Pathways in Females with Overweight and Obesity

SCOPE

Low-calorie sweetener (LCS) consumption is associated with metabolic disease in observational studies. However, physiologic mechanisms underlying LCS-induced metabolic impairments in humans are unclear. This study is aimed at identifying molecular pathways in adipose impacted by LCSs.

METHODS AND RESULTS

Seven females with overweight or obesity, who did not report LCS use, consumed 12 ounces of diet soda containing sucralose and acesulfame-potassium (Ace-K) three times daily for 8 weeks. A subcutaneous adipose biopsy from the left abdomen and a fasting blood sample were collected at baseline and post-intervention. Global gene expression were assessed using RNA-sequencing followed by functional pathway analysis. No differences in circulating metabolic or inflammatory biomarkers were observed. However, ANOVA detected 828 differentially expressed annotated genes after diet soda consumption (p < 0.05), including transcripts for inflammatory cytokines. Fifty-eight of 140 canonical pathways represented in pathway analyses regulated inflammation, and several key upstream regulators of inflammation (e.g., TNF-alpha) were also represented.

CONCLUSION

Consumption of diet soda with sucralose and Ace-K alters inflammatory transcriptomic pathways (e.g., NF-κB signaling) in subcutaneous adipose tissue but does not significantly alter circulating biomarkers. Findings highlight the need to examine molecular and metabolic effects of LCS exposure in a larger randomized control trial for a longer duration.

Chronic sucralose consumption induces elevation of serum insulin in young healthy adults: a randomized, double blind, controlled trial

BACKGROUND

Non-nutritive sweeteners (NNS) are widely consumed by humans due to their apparent innocuity, especially sucralose. However, several studies link sucralose consumption to weight gain and metabolic derangements, although data are still contradictory.

OBJECTIVE

To determine the effect of acute and chronic consumption of sucralose on insulin and glucose profiles in young healthy adults.

MATERIAL AND METHODS

This was a randomized, parallel, double-blind, placebo-controlled trial conducted in healthy young adults from 18 to 35 years old, without insulin resistance. A hundred thirty seven participants were randomized into three groups: a) volunteers receiving 48 mg sucralose, b) volunteers receiving 96 mg sucralose, and c) controls receiving water as placebo. All participants underwent a 3-h oral glucose tolerance test (OGTT) preceded by consuming sucralose or placebo 15 min before glucose load, at two time points: week zero (Wk0) and week ten (Wk10). Serum insulin and glucose were measured every 15 min during both OGTTs.

RESULTS

Compared to Wk0, consumption of sucralose for 10 weeks provoked 1) increased insulin concentrations at 0 min (7.5 ± 3.4 vs 8.8 ± 4.1 μIU/mL; p = 0.01), 30 min (91.3 ± 56.2 vs 110.1 ± 49.4 μIU/mL; p = 0.05), 105 min (47.7 ± 24.4 vs 64.3 ± 48.2 μIU/mL; p = 0.04) and 120 min (44.8 ± 22.1 vs 63.1 ± 47.8 μIU/mL; p = 0.01) in the 48 mg sucralose group; 2) increased blood glucose at - 15 min (87.9 ± 4.6 vs 91.4 ± 5.4 mg/dL; p = 0.003), 0 min (88.7 ± 4 vs 91.3 ± 6 mg/dL; p = 0.04) and 120 min (95.2 ± 23.7 vs 106.9 ± 19.5 mg/dL; p = 0.009) in the 48 mg sucralose group; 3) increased area under the curve (AUC) of insulin in both 48 and 96 mg sucralose groups (9262 vs 11,398; p = 0.02 and 6962 vs 8394; p = 0.12, respectively); and 4) reduced Matsuda index in the 48 mg sucralose group (6.04 ± 3.19 vs 4.86 ± 2.13; p = 0.01).

CONCLUSIONS

These data show that chronic consumption of sucralose can affect insulin and glucose responses in non-insulin resistant healthy young adults with normal body mass index (between 18.5 and 24.9 kg/m2), however, the effects are not consistent with dose; further research is required.

CLINICAL TRIAL REGISTRY

NCT03703141.

Short-Term Consumption of Sucralose with, but Not without, Carbohydrate Impairs Neural and Metabolic Sensitivity to Sugar in Humans

There is a general consensus that overconsumption of sugar-sweetened beverages contributes to the prevalence of obesity and related comorbidities such as type 2 diabetes (T2D). Whether a similar relationship exists for no- or low-calorie "diet" drinks is a subject of intensive debate and controversy. Here, we demonstrate that consuming seven sucralose-sweetened beverages with, but not without, a carbohydrate over 10 days decreases insulin sensitivity in healthy human participants, an effect that correlates with reductions in midbrain, insular, and cingulate responses to sweet, but not sour, salty, or savory, taste as assessed with fMRI. Taste perception was unaltered and consuming the carbohydrate alone had no effect. These findings indicate that consumption of sucralose in the presence of a carbohydrate rapidly impairs glucose metabolism and results in longer-term decreases in brain, but not perceptual sensitivity to sweet taste, suggesting dysregulation of gut-brain control of glucose metabolism.

Non-nutritive Sweeteners and Glycaemic Control

PURPOSE OF REVIEW

The consumption of foods and beverages containing non-nutritive sweeteners (NNS) has increased worldwide over the last three decades. Consumers' choice of NNS rather than sugar or other nutritive sweeteners may be attributable to their potential to reduce weight gain.

RECENT FINDINGS

It is not clear what the effects of NNS consumption are on glycaemic control and the incidence of type 2 diabetes. This review aims to examine this question in epidemiological, human intervention and animal studies. It is not clear that NNS consumption has an effect on the incidence of type 2 diabetes or on glycaemic control even though there is some evidence for the modification of the microbiome and for interaction with sweet taste receptors in the oral cavity and the intestines' modification of secretion of glucagon-like peptide-1 (GLP-1), peptide YY (PYY), ghrelin and glucose-dependent insulinotropic polypeptide (GIP), which may affect glycaemia following consumption of NNS. In conclusion, long-term studies of NNS consumption are required to draw a firm conclusion about the role of NNS consumption on glycaemic control.

Low Calorie Sweeteners Differ in Their Physiological Effects in Humans

Low calorie sweeteners (LCS) are prevalent in the food supply for their primary functional property of providing sweetness with little or no energy. Though tested for safety individually, there has been extremely limited work on the efficacy of each LCS. It is commonly assumed all LCS act similarly in their behavioral and physiological effects. However, each LCS has its own chemical structure that influences its metabolism, making each LCS unique in its potential effects on body weight, energy intake, and appetite. LCS may have different behavioral and physiological effects mediated at the sweet taste receptor, in brain activation, with gut hormones, at the microbiota and on appetitive responses. Further elucidation of the unique effects of the different commercially available LCS may hold important implications for recommendations about their use for different health outcomes.

The effect of the artificial sweeteners on glucose metabolism in healthy adults: a randomized, double-blinded, crossover clinical trial

This study aimed to determine the effect of pure forms of sucralose and aspartame, in doses reflective of common consumption, on glucose metabolism. Healthy participants consumed pure forms of a non-nutritive sweetener (NNS) that were mixed with water and standardized to doses of 14% (0.425 g) of the acceptable daily intake (ADI) for aspartame and 20% (0.136 g) of the ADI for sucralose every day for 2 weeks. Blood samples were collected and analyzed for glucose, insulin, active glucagon-like peptide-1 (GLP-1), and leptin. Seventeen participants (10 females and 7 males; age, 24 ± 6.8 years; body mass index, 22.9 ± 2.5 kg/m²) participated in the study. The total area under the curve values of glucose, insulin, active GLP-1 and leptin were similar for the aspartame and sucralose treatment groups compared with the baseline values in healthy participants. There was no change in insulin sensitivity after NNS treatment compared with the baseline values. These findings suggest that daily repeated consumption of pure sucralose or aspartame for 2 weeks had no effect on glucose metabolism among normoglycaemic adults. However, these results need to be tested in studies with longer durations. Novelty Daily consumption of pure aspartame or sucralose for 2 weeks had no effect on glucose metabolism. Daily consumption of pure aspartame or sucralose for 2 weeks had no effect on insulin sensitivity among healthy adults.

Low-calorie sweeteners cause only limited metabolic effects in mice

There are widespread concerns that low-calorie sweeteners (LCSs) cause metabolic derangement. These concerns stem in part from prior studies linking LCS consumption to impaired glucose tolerance in humans and rodents. Here, we examined this linkage in mice. In experiment 1, we provided mice with chow, water, and an LCS-sweetened solution (saccharin, sucralose, or acesulfame K) for 28 days and measured glucose tolerance and body weight across the exposure period. Exposure to the LCS solutions did not impair glucose tolerance or alter weight gain. In experiment 2, we provided mice with chow, water, and a solution containing saccharin, glucose, or a mixture of both for 28 days, and tested for metabolic changes. Exposure to the saccharin solution increased the insulinemic response of mice to the glucose challenge, and exposure to the saccharin + glucose solution increased the rate of glucose uptake during the glucose challenge. However, neither of these test solutions altered glucose tolerance, insulin sensitivity, plasma triglycerides, or percent body fat. In contrast, exposure to the glucose solution increased glucose tolerance, early insulin response, insulin sensitivity, and percent body fat. We conclude that whereas the LCS-containing solutions induced a few metabolic changes, they were modest compared with those induced by the glucose solution.

Moderate intake of aspartame and sucralose with meals, but not fructose, does not exacerbate energy and glucose metabolism in estrogen-deficient rats

Both nutritive and non-nutritive sweeteners may influence energy and glucose metabolism differently. The hypothesis that sucrose, fructose, aspartame, and sucralose intake differently modulate energy and glucose metabolism was tested in an estrogen-deficient animal model. At 30 min after giving aspartame and sucralose (10 mg/kg body weight), an oral glucose tolerance test (OGTT) was conducted with glucose, sucrose, and fructose in ovariectomized (OVX) rats. After OGTT, they were continuously fed high fat diets including either 10% corn starch (Control), 10% sucrose (Sucrose), 10% fructose (Fructose), 0.05% aspartame + 9.95% starch (Aspartame) or 0.05% sucralose + 9.95% starch (Sucralose) for 8 week. During 30 min after acute administration of aspartame and sucralose, serum glucose concentrations increased despite slightly increased serum insulin levels before glucose infusion. However, glucose tolerance was not significantly different among the groups. In chronic study, serum glucose concentrations were lowest and insulin highest at the overnight-fasted state in Aspartame and Sucralose. Postprandial serum glucagon-like peptide-1 (GLP-1) and insulin levels were higher in Aspartame and Sucralose than Control. Hepatic insulin signaling (pAkt → pGSK-3β) and phosphoenolpyruvate carboxykinase (PEPCK) expression were lower in Sucralose and Aspartame than the Fructose. Serum acetate levels produced by gut microbiota were higher were lower in the fructose group than Aspartame and Sucralose groups. In conclusion, aspartame and sucralose with a meal might be preferable sweeteners to fructose and sucrose in estrogen deficient rats, and possibly post-menopausal women; however, this needs to be confirmed in human studies.

A Single 48 mg Sucralose Sip Unbalances Monocyte Subpopulations and Stimulates Insulin Secretion in Healthy Young Adults

Sucralose is a noncaloric artificial sweetener that is widely consumed worldwide and has been associated with alteration in glucose and insulin homeostasis. Unbalance in monocyte subpopulations expressing CD11c and CD206 hallmarks metabolic dysfunction but has not yet been studied in response to sucralose. Our goal was to examine the effect of a single sucralose sip on serum insulin and blood glucose and the percentages of classical, intermediate, and nonclassical monocytes in healthy young adults subjected to an oral glucose tolerance test (OGTT). This study was a randomized, placebo-controlled clinical trial. Volunteers randomly received 60 mL water as placebo (n = 20) or 48 mg sucralose dissolved in 60 mL water (n = 25), fifteen minutes prior to an OGTT. Blood samples were individually drawn every 15 minutes for 180 minutes for quantifying glucose and insulin concentrations. Monocyte subsets expressing CD11c and CD206 were measured at -15 and 180 minutes by flow cytometry. As compared to controls, volunteers receiving sucralose exhibited significant increases in serum insulin at 30, 45, and 180 minutes, whereas blood glucose values showed no significant differences. Sucralose consumption caused a significant 7% increase in classical monocytes and 63% decrease in nonclassical monocytes with respect to placebo controls. Pearson's correlation models revealed a strong association of insulin with sucralose-induced monocyte subpopulation unbalance whereas glucose values did not show significant correlations. Sucralose ingestion decreased CD11c expression in all monocyte subsets and reduced CD206 expression in nonclassical monocytes suggesting that sucralose does not only unbalance monocyte subpopulations but also alter their expression pattern of cell surface molecules. This work demonstrates for the first time that a 48 mg sucralose sip increases serum insulin and unbalances monocyte subpopulations expressing CD11c and CD206 in noninsulin-resistant healthy young adults subjected to an OGTT. The apparently innocuous consumption of sucralose should be reexamined in light of these results.

A randomized controlled trial contrasting the effects of 4 low-calorie sweeteners and sucrose on body weight in adults with overweight or obesity

BACKGROUND

Low-calorie sweeteners (LCSs) provide sweetness with little or no energy. However, each LCS's unique chemical structure has potential to elicit different sensory, physiological, and behavioral responses that affect body weight.

OBJECTIVE

The purpose of this trial was to compare the effects of consumption of 4 LCSs and sucrose on body weight, ingestive behaviors, and glucose tolerance over a 12-wk intervention in adults (18-60 y old) with overweight or obesity (body mass index 25-40 kg/m2).

METHODS

In a parallel-arm design, 154 participants were randomly assigned to consume 1.25-1.75 L of beverage sweetened with sucrose (n = 39), aspartame (n = 30), saccharin (n = 29), sucralose (n = 28), or rebaudioside A (rebA) (n = 28) daily for 12 wk. The beverages contained 400-560 kcal/d (sucrose treatments) or <5 kcal/d (LCS treatments). Anthropometric indexes, energy intake, energy expenditure, appetite, and glucose tolerance were measured at baseline. Body weight was measured every 2 wk with energy intake, expenditure, and appetite assessed every 4 wk. Twenty-four-hour urine collections were completed every 4 wk to determine study compliance via para-aminobenzoic acid excretion.

RESULTS

Of the participants enrolled in the trial, 123 completed the 12-wk intervention. Sucrose and saccharin consumption led to increased body weight across the 12-wk intervention (Δweight = +1.85 ± 0.36 kg and +1.18 ± 0.36 kg, respectively; P ≤ 0.02) and did not differ from each other. There was no significant change in body weight with consumption of the other LCS treatments compared with baseline, but change in body weight for sucralose was negative and significantly lower compared with all other LCSs at week 12 (weight difference ≥ 1.37 ± 0.52 kg, P ≤ 0.008). Energy intake decreased with sucralose consumption (P = 0.02) and ingestive frequency was lower for sucralose than for saccharin (P = 0.045). Glucose tolerance was not significantly affected by any of the sweetener treatments.

CONCLUSIONS

Sucrose and saccharin consumption significantly increase body weight compared with aspartame, rebA, and sucralose, whereas weight change was directionally negative and lower for sucralose compared with saccharin, aspartame, and rebA consumption. LCSs should be categorized as distinct entities because of their differing effects on body weight. This trial was registered at clinicaltrials.gov as NCT02928653.

The acute effects of the non-nutritive sweeteners aspartame and acesulfame-K in UK diet cola on glycaemic response

Substituting sugar-sweetened for artificially sweetened beverages may reduce energy intakes. This study aims to ascertain the acute glycaemic effects of the NNS aspartame and acesulfame-K in UK diet-cola (DC). Ten healthy participants attended the laboratory fasted on three occasions. Individuals drank (1) 25 g glucose in 125 mL water + 236 mL water, (2) 25 g glucose in 125 mL water with 236 mL DC and (3) 236 mL sucrose-sweetened cola with 125 mL water. Blood (glucose) was measured pre-test and every 15 minutes over a 120-minute period using portable glucometers. The glucose-control and glucose + DC elicited similar blood glucose rises above pre-prandial levels. Sucrose-sweetened cola showed a non-significant lower rise in postprandial glycaemia, exhibiting the lowest glycaemic index (GI) (77.0 ± 9.1). GI of glucose (100.0 ± 15.2) and glucose + DC (104.3 ± 8.5) was similar and a one-way repeated-measures ANOVA showed no significant differences in glycaemic response between test drinks (F(2,29) = 1.68, p > .05). Results demonstrate the glycaemic inactivity of non-nutritive sweeteners.

Beyond the Flavour: The Potential Druggability of Chemosensory G Protein-Coupled Receptors

G protein-coupled receptors (GPCRs) belong to the largest class of drug targets. Approximately half of the members of the human GPCR superfamily are chemosensory receptors, including odorant receptors (ORs), trace amine-associated receptors (TAARs), bitter taste receptors (TAS2Rs), sweet and umami taste receptors (TAS1Rs). Interestingly, these chemosensory GPCRs (csGPCRs) are expressed in several tissues of the body where they are supposed to play a role in biological functions other than chemosensation. Despite their abundance and physiological/pathological relevance, the druggability of csGPCRs has been suggested but not fully characterized. Here, we aim to explore the potential of targeting csGPCRs to treat diseases by reviewing the current knowledge of csGPCRs expressed throughout the body and by analysing the chemical space and the drug-likeness of flavour molecules.

Metabolic consequences of discretionary fortified beverage consumption containing excessive vitamin B levels in adolescents

Over the past decade, there has been a substantial increase in the number of beverage products containing added vitamins and minerals. Often viewed as a healthier choice by consumers, the metabolic impacts of excessive vitamin consumption are relatively unknown, especially in children. The aim of this study was to examine the effects of a widely available, vitamin fortified beverage (5h Energy Decaffeinated) on insulin sensitivity, metabolic hormones and serum metabolomic responses in adolescents. Twenty adolescents (13-19y, 10M/10F) completed two randomized trials, consuming either coloured water as placebo (PL) or a vitamin fortified, sugar free beverage (FB, 1.5ml/kg) 40min prior to a modified oral glucose tolerance test (OGTT, 1.75g/kg glucose). Samples were collected at baseline and at 30, 45, 60, 90 and 120min during the OGTT. No differences in blood glucose response were observed between the treatments. However, compared to PL, postprandial plasma C-peptide and insulin excursion was significantly greater with FB, resulting in a 28% decline in the insulin sensitivity index. This was accompanied by elevated GLP-1, glucagon and PYY responses with FB compared to PL. Serum metabolomics (¹H-NMR) analysis also revealed perturbations to vitamin B-linked one carbon metabolism flux with FB consumption that became more pronounced over time. These included a transient reduction in homocysteine flux accompanied by increases in betaine, vitamin B6, vitamin B12, choline, folate and taurine. Although these impacts are likely short-lived, results show that beverages fortified with excessive amounts of vitamins are not metabolically inert, but likely result in greater insulin secretion, differential gut hormone secretion and elevated one-carbon flux to process the excessive vitamin loads.

Metabolic Effects of Low-Calorie Sweeteners: A Brief Review

Low-calorie sweeteners (LCS) are found in a variety of foods and beverages, yet their role in diet, weight, and obesity-related chronic disease is controversial. This article summarizes proceedings from one of four presentations during a preconference session entitled "Low-Calorie Sweeteners and Weight Management," which took place at the 2017 Obesity Society Annual Meeting in Washington, District of Columbia. The objective of this brief review is to summarize findings of observational and interventional studies of LCS effects on weight and metabolic health and to provide potential explanations for their discrepant results. Key research priorities for advancing the understanding of the role of LCS in weight and chronic disease are also discussed. The existing literature suggests that LCS consumption is consistently associated with obesity, diabetes, and related cardiometabolic conditions in observational studies. Although several plausible mechanisms have been proposed to explain these associations and have received considerable support in cellular and rodent models, the relevance of these mechanisms to humans has yet to be confirmed. Meanwhile, randomized controlled trials demonstrate that NNS may benefit weight loss and weight maintenance. This is the case particularly when LCS are administered in the context of behavioral weight loss support and are consumed knowingly by habitual LCS consumers. Although these findings suggest that LCS may be useful for weight control among those cognitively engaged in weight loss and who are aware of their LCS consumption, LCS administration in these studies does not reflect typical consumption. Furthermore, few interventional studies have assessed the role of LCS on metabolic outcomes other than body weight. Additional factors must be considered before recommending LCS for weight management and chronic disease prevention and further study of LCS effects on a variety of cardiometabolic outcomes, including visceral adiposity and glucose homeostasis is warranted.

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

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.

How Non-nutritive Sweeteners Influence Hormones and Health

Non-nutritive sweeteners (NNSs) elicit a multitude of endocrine effects in vitro, in animal models, and in humans. The best-characterized consequences of NNS exposure are metabolic changes, which may be mediated by activation of sweet taste receptors in oral and extraoral tissues (e.g., intestine, pancreatic β cells, and brain), and alterations of the gut microbiome. These mechanisms are likely synergistic and may differ across species and chemically distinct NNSs. However, the extent to which these hormonal effects are clinically relevant in the context of human consumption is unclear. Further investigation following prolonged exposure is required to better understand the role of NNSs in human health, with careful consideration of genetic, dietary, anthropometric, and other interindividual differences.

Diet Soda and Sugar-Sweetened Soda Consumption in Relation to Incident Diabetes in the Northern Manhattan Study

BACKGROUND

Artificially (diet) and sugar-sweetened (regular) soda consumption have been associated with an increased risk of diabetes, but the literature on diet soda is inconsistent and the mechanisms unclear.

OBJECTIVE

We examined the relation between diet soda and regular soda consumption with the risk of incident diabetes in a longitudinal multiethnic population-based cohort.

METHODS

The study population included 2019 participants (mean ± SD age:  69 ± 10 y; 64% women; 23% white, 22% black, 53% Hispanic) in the Northern Manhattan Study who were free of diabetes and stroke at baseline. Soda consumption was assessed by a food-frequency questionnaire at baseline and examined continuously and categorically (<1/mo: sugar-sweetened = 908, diet = 1615; 1/mo-6/wk: sugar-sweetened = 830, diet = 298; daily: sugar-sweetened = 281, diet = 106). Weibull regression models were used to estimate the associations between soda consumption and incident diabetes, adjusting for demographics and vascular risk factors including body mass index (BMI) and calorie consumption.

RESULTS

During a mean ± SD follow-up of 11 ± 5 y, 368 participants developed diabetes. Sugar-sweetened soda was positively associated with incident diabetes (per soda per day HR = 1.15, 95% CI:  1.02, 1.31). The observed association between diet soda and elevated risk of diabetes was largely explained by BMI at the time of diet assessment, though the association remained strong and independent of BMI among those who were overweight or obese (daily compared to <1/mo: HR = 1.63, 95% CI:  1.04, 2.55).

CONCLUSIONS

This study supports the importance of sugar-sweetened beverage consumption in the diabetes epidemic. However, the results support previous studies suggesting that switching to artificially sweetened diet beverages may not lower the risk of diabetes, as diet soda consumption cannot be ruled out as an independent diabetes risk factor.

Aspartame Consumption for 12 Weeks Does Not Affect Glycemia, Appetite, or Body Weight of Healthy, Lean Adults in a Randomized Controlled Trial

Background

Low-calorie sweeteners are often used to moderate energy intake and postprandial glycemia, but some evidence indicates that they may exacerbate these aims.

Objective

The trial's primary aim was to assess the effect of daily aspartame ingestion for 12 wk on glycemia. Effects on appetite and body weight were secondary aims.

Methods

One hundred lean [body mass index (kg/m2): 18-25] adults aged 18-60 y were randomly assigned to consume 0, 350, or 1050 mg aspartame/d (ASP groups) in a beverage for 12 wk in a parallel-arm design. At baseline, body weight and composition were determined, a 240-min oral-glucose-tolerance test (OGTT) was administered, and measurements were made of appetite and selected hormones. Participants also collected a 24-h urine sample. During the intervention, the 0-mg/d ASP group consumed capsules containing 680 mg dextrose and 80 mg para-amino benzoic acid. For the 350-mg/d ASP group, the beverage contained 350 mg aspartame and the 1050-mg/d ASP group consumed the same beverage plus capsules containing 680 mg dextrose and 700 mg aspartame. Body weight, blood pressure, heart rate, and waist circumference were measured weekly. At weeks 4, 8, and 12, participants collected 24-h urine samples and kept appetite logs. Baseline measurements were repeated at week 12.

Results

With the exception of the baseline OGTT glucose concentration at 60 min (and resulting area under the curve value), there were no group differences for glucose, insulin, resting leptin, glucagon-like peptide 1, or gastric inhibitory peptide at baseline or week 12. There also were no effects of aspartame ingestion on appetite, body weight, or body composition. Compliance with the beverage intervention was ∼95%.

Conclusions

Aspartame ingested at 2 doses for 12 wk had no effect on glycemia, appetite, or body weight among healthy, lean adults. These data do not support the view that aspartame is problematic for the management of glycemia, appetite, or body weight. This trial was registered at www.clinicaltrials.gov as NCT02999321.

Nonnutritive Sweeteners in Weight Management and Chronic Disease: A Review

OBJECTIVE

The objective of this review was to critically review findings from recent studies evaluating the effects of nonnutritive sweeteners (NNSs) on metabolism, weight, and obesity-related chronic diseases. Biologic mechanisms that may explain NNS effects will also be addressed.

METHODS

A comprehensive review of the relevant scientific literature was conducted.

RESULTS

Most cross-sectional and prospective cohort studies report positive associations between NNS consumption, body weight, and health conditions, including type 2 diabetes, cardiovascular disease, and nonalcoholic fatty liver disease. Although findings in cellular and rodent models suggest that NNSs have harmful effects on metabolic health, most randomized controlled trials in humans demonstrate marginal benefits of NNS use on body weight, with little data available on other metabolic outcomes.

CONCLUSIONS

NNS consumption is associated with higher body weight and metabolic disease in observational studies. In contrast, randomized controlled trials demonstrate that NNSs may support weight loss, particularly when used alongside behavioral weight loss support. Additional long-term, well-controlled intervention studies in humans are needed to determine the effects of NNSs on weight, adiposity, and chronic disease under free-living conditions.

A workshop on 'Dietary Sweetness-Is It an Issue?'

This report summarises a workshop convened by ILSI Europe on 3 and 4 April 2017 to discuss the issue of dietary sweetness. The objectives were to understand the roles of sweetness in the diet, establish whether exposure to sweetness affects diet quality and energy intake, and consider whether sweetness per se affects health. Although there may be evidence for tracking of intake of some sweet components of the diet through childhood, evidence for tracking of whole diet sweetness, or through other stages of maturity are lacking. The evidence to date does not support adverse effects of sweetness on diet quality or energy intake, except where sweet food choices increase intake of free sugars. There is some evidence for improvements in diet quality and reduced energy intake where sweetness without calories replaces sweetness with calories. There is a need to understand the physiological and metabolic relevance of sweet taste receptors on the tongue, in the gut and elsewhere in the body, as well as possible differentiation in the effects of sustained consumption of individual sweeteners. Despite a plethora of studies, there is no consistent evidence for an association of sweetness sensitivity/preference with obesity or type 2 diabetes. A multifaceted integrated approach, characterising nutritive and sensory aspects of the whole diet or dietary patterns, may be more valuable in providing contextual insight. The outcomes of the workshop could be used as a scientific basis to inform the expert community and create more useful dialogue among health care professionals.

Intake of non-nutritive sweeteners is associated with an unhealthy lifestyle: a cross-sectional study in subjects with morbid obesity

Background

Subjects with morbid obesity commonly use Non-Nutritive Sweeteners (NNS), but the health-related effects of NNS have been questioned. The objectives of this study were to explore the associations between theuse of NNS and the health and lifestyle in subjects with morbid obesity.

Methods

This cross-sectional study included subjects with morbid obesity (BMI ≥ 40 kg/m² or ≥35 kg/m² with obesity-related comorbidity). Information about demographics, physical and mental health, and dietary habits was collected, and a blood screen was taken. One unit of NNS was defined as 100 ml beverages with NNS or 2 tablets/units of NNS for coffee or tea. The associations between the intake of NNS and the health-related variables were analyzed with ordinal regression analyses adjusted for age, gender and BMI.

Results

One hundred subjects (women/men 83/17; mean age 44.3 years (SD 8.5)) were included. Median intake of NNS was 3.3 units (range 0 - 43). Intake of NNS was not associated with BMI (p = 0.64). The intake of NNS was associated with reduced heavy physical activity (p = 0.011), fatigue (p < 0.001), diarrhea (p = 0.009) and reduced well-being (p = 0.046); with increased intake of total energy (p = 0.003), fat (p = 0.013), carbohydrates (p = 0.002), sugar (p = 0.003) and salt (p = 0.001); and with reduced intake of the vitamins A (p = 0.001), C (p = 0.002) and D (p = 0.016).

Conclusions

The use of NNS-containing beverages was associated with an unhealthy lifestyle, reduced physical and mental health and unfavourable dietary habits with increased energy intake including sugar, and reduced intake of some vitamins.

Low-Calorie Sweeteners: Disturbing the Energy Balance Equation in Adolescents?

OBJECTIVE

The aim of this study was to investigate the relationship between low-calorie sweeteners (LCSs), energy intake, and weight in US youth.

METHODS

Data were collected from individuals aged 2 to 19 years who participated in the National Health and Nutrition Examination Survey (NHANES) 2009-2010 (n  =  3,296), 2011-2012 (n  =  3,139), and 2013-2014 (n  =  3,034). Logistic regression, unadjusted and adjusted for age, sex, race/ethnicity, income, energy intake, and physical activity, was used to estimate the odds of obesity in LCS consumers versus nonconsumers, both overall and across product categories (foods vs. beverages) and sociodemographic subgroups.

RESULTS

Among adolescents, the odds of obesity were 55% and 70% higher in LCS beverage consumers than in nonconsumers in unadjusted and adjusted models, respectively. Energy intakes did not differ based on LCS consumption. In contrast, associations between LCS consumption and obesity risk were not statistically significant among children (2-11 y old), except in boys and those who self-identified as Hispanic.

CONCLUSIONS

LCS consumption is associated with increased odds of obesity among adolescents. This relationship is strikingly independent of total energy intake. Although findings should be interpreted cautiously because of the limitations of self-reported dietary intake and the cross-sectional nature of this analysis, the observational analysis in this study supports the need to investigate the mechanisms by which LCS may influence body weight, independently of changes in energy intake.

The cephalic phase insulin response to nutritive and low-calorie sweeteners in solid and beverage form

The purpose of the study was to examine the role of the cephalic phase insulin response (CPIR) following exposure to nutritive and low-calorie sweeteners in solid and beverage form in overweight and obese adults. In addition, the role of learning on the CPIR to nutritive and low-calorie sweetener exposure was tested. Sixty-four overweight and obese adults (age: 18-50years, BMI: 24-37kg/m2, body fat percentage>25% for men and >32% for women) were sham-fed (at 2-minute intervals for 14min) a randomly assigned test load comprised of a nutritive (sucrose) or low-calorie sweetener (sucralose) in beverage or solid form in phase 1 of the study. A 2-3ml blood sample was collected before and 2, 6, 10, 14, 61, 91 and 121min after oral exposure for serum insulin and glucose analysis. During phase 2, participants underwent a 2-week training period to facilitate associative learning between the sensory properties of test loads and their post-ingestive effects. In phase 3, participants were retested for their cephalic phase responses as in phase 1. Participants were classified as responders if they demonstrated a positive insulin response (rise of serum insulin above baseline i.e. Δ insulin) 2min post-stimulus in phase 1. Among responders exposed to the same sweetener in Phases 1 and 3, the proportion of participants that displayed a rise of insulin with oral exposure to sucralose was significantly greater when the stimulus was in the solid form compared to the beverage form. Sucralose and sucrose exposure elicited similarly significant increases in serum insulin 2min after exposure and significant decreases after 2min in responders in both food forms. The solid food form elicited greater CPIR over 2, 6 and 10min than the beverage form. There was no effect of learning on insulin responses after training. The results indicate the presence of a significant CPIR in a subset of individuals with overweight or obesity after oral exposure to sucralose, especially when present in solid food form. Future studies must confirm the reliability of this response.