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

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.

Sweeteners in Brazilian processed foods and beverages: prevalence, profile and concomitant addition of sugars and nutritional claims

Brazil is experiencing an increased prevalence of overweight and obesity. To overcome these health problems, several strategies have been implemented, including incentives to reduce sugar intake and new packaging labeling. This has promoted an increase in the use of low or non-caloric sweeteners (LNCS). In this study, the use of LNCS in six Brazilian food groups (non-alcoholic beverages, dairy products, baked goods, confectionery, cereals, and condiments) was investigated through label declarations. Three supermarkets were visited in Belo Horizonte, MG, Brazil. Ten out of the 16 LNCS allowed by the Brazilian legislation were declared. Altogether, among the 441 products included, 17.7% contained at least one LNCS, with an average of 2.21 LNCS per sweetened product. Non-alcoholic beverages (37.2%) and dairy products (29.5%) had the highest LNCS occurrence. Combinations of two, three, four, and seven LNCS were found. Artificial sweeteners represented 87.8% of the declared LNCS, with a higher prevalence of acesulfame-K, followed by cyclamate, and sucralose, respectively. Meanwhile, 53.9% of 78 products containing LNCS also had added sugars, and 70.5% used nutritional claims about reduced sugars and/or calories. This scenario highlights the importance of continuous monitoring of LNCS in foods and beverages as front-of-package labeling is not fully implemented yet.

Sugar and low/no-calorie-sweetened beverage consumption and associations with body weight and waist circumference changes in five European cohort studies: the SWEET project

PURPOSE

Results of prospective studies investigating associations between low/no-calorie sweeteners (LNCS) and body weight-related outcomes are inconclusive. We conducted dose-response and theoretical replacement individual patient data meta-analyses using harmonised prospective data to evaluate associations between sugar-sweetened beverage (SSB) consumption, low/no-calorie sweetened beverage (LNCB) consumption, and changes in body weight and waist circumference.

METHODS

Individual participant data were obtained from five European studies, i.e., Lifelines Cohort Study, NQplus study, Alpha Omega Cohort, Predimed-Plus study, and Feel4diabetes study, including 82,719 adults aged 18-89 with follow-up between 1 and 9 years. Consumption of SSB and LNCB was assessed using food-frequency questionnaires. Multiple regression analyses adjusting for major confounders and including substitution models were conducted to quantify associations in individual cohorts; random-effects meta-analyses were performed to pool individual estimates.

RESULTS

Overall, pooled results showed weak adverse associations between SSB consumption and changes in body weight (+ 0.02 kg/y, 95%CI 0.00; 0.04) and waist circumference (+ 0.03 cm/y, 95%CI 0.01; 0.05). LNCB consumption was associated with higher weight gain (+ 0.06 kg/y, 95%CI 0.04; 0.08) but not with waist circumference. No clear associations were observed for any theoretical replacements, i.e., LNCB or water for SSB or water for LNCB.

CONCLUSION

In conclusion, this analysis of five European studies found a weak positive association between SSB consumption and weight and waist change, whilst LNCB consumption was associated with weight change only. Theoretical substitutions did not show any clear association. Thus, the benefit of LNCBs as an alternative to SSBs remains unclear.

Impact of acute consumption of beverages containing plant-based or alternative sweetener blends on postprandial appetite, food intake, metabolism, and gastro-intestinal symptoms: Results of the SWEET beverages trial

Project SWEET examined the barriers and facilitators to the use of non-nutritive sweeteners and sweetness enhancers (hereafter "S&SE") alongside potential risks/benefits for health and sustainability. The Beverages trial was a double-blind multi-centre, randomised crossover trial within SWEET evaluating the acute impact of three S&SE blends (plant-based and alternatives) vs. a sucrose control on glycaemic response, food intake, appetite sensations and safety after a carbohydrate-rich breakfast meal. The blends were: mogroside V and stevia RebM; stevia RebA and thaumatin; and sucralose and acesulfame-potassium (ace-K). At each 4 h visit, 60 healthy volunteers (53% male; all with overweight/obesity) consumed a 330 mL beverage with either an S&SE blend (0 kJ) or 8% sucrose (26 g, 442 kJ), shortly followed by a standardised breakfast (∼2600 or 1800 kJ with 77 or 51 g carbohydrates, depending on sex). All blends reduced the 2-h incremental area-under-the-curve (iAUC) for blood insulin (p < 0.001 in mixed-effects models), while the stevia RebA and sucralose blends reduced the glucose iAUC (p < 0.05) compared with sucrose. Post-prandial levels of triglycerides plus hepatic transaminases did not differ across conditions (p > 0.05 for all). Compared with sucrose, there was a 3% increase in LDL-cholesterol after stevia RebA-thaumatin (p < 0.001 in adjusted models); and a 2% decrease in HDL-cholesterol after sucralose-ace-K (p < 0.01). There was an impact of blend on fullness and desire to eat ratings (both p < 0.05) and sucralose-acesulfame K induced higher prospective intake vs sucrose (p < 0.001 in adjusted models), but changes were of a small magnitude and did not translate into energy intake differences over the next 24 h. Gastro-intestinal symptoms for all beverages were mostly mild. In general, responses to a carbohydrate-rich meal following consumption of S&SE blends with stevia or sucralose were similar to sucrose.

Low-Grade Inflammation and Ultra-Processed Foods Consumption: A Review

Low-grade inflammation alters the homeostasis of the organism and favors the onset of many chronic diseases. The global growth in the prevalence of noncommunicable diseases in recent years has been accompanied by an increase in the consumption of ultra-processed foods (UPF). Known to be hyperpalatable, economic and ready-to-eat, increased consumption of UPF has already been recognized as a risk factor for several chronic diseases. Different research groups have tried to investigate whether UPF consumption could promote low-grade inflammation and thus favor the development of noncommunicable diseases. Current evidence highlights the adverse health effects of UPF characteristics, not only due to the nutrients provided by a diet rich in UPF, but also due to the non-nutritive components present in UPF and the effect they may have on gut health. This review aims to summarize the available evidence on the possible relationship between excessive UPF consumption and modulation of low-grade inflammation, as potential promoters of chronic disease.

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.

High Blood Glucose and Excess Body fat Enhance Pain Sensitivity and Weaken Pain Inhibition in Healthy Adults: A Single-blind Cross-over Randomized Controlled Trial

To investigate links between blood glucose, body fat mass and pain, the effects of acute hyperglycaemia on pain sensitivity and pain inhibition were examined in healthy adults with normal (n = 24) or excess body fat (n = 20) determined by dual-energy X-ray absorptiometry. Effects of hyperglycaemia on heart rate variability and reactive hyperaemia were also explored. For the overall sample, ingesting 75-g glucose enhanced pain sensitivity during 1-minute cold-water immersion of both feet (conditioning stimulus) and weakened the pain inhibitory effect of cold water on pressure pain thresholds (test stimulus). Exploratory subgroup analyses not adjusted for multiple comparisons suggested that this effect was limited to people with excess fat mass. In addition, acute hyperglycaemia suppressed resting heart rate variability only in people with excess fat mass. Furthermore, regardless of blood glucose levels, people with excess fat mass had weaker pain inhibition for pinprick after cold water and reported more pain during 5-minutes of static blood flow occlusion. Neither high blood glucose nor excess body fat affected pinprick-temporal summation of pain or reactive hyperaemia. Together, these findings suggest that hyperglycaemia and excess fat mass interfere with pain processing and autonomic function. PERSPECTIVE: Ingesting 75-g glucose (equivalent to approximately 2 standard cans of soft drink) interfered with pain-processing and autonomic function, particularly in people with excess body fat mass. As both hyperglycaemia and overweight are risk factors for diabetes, whether these are sources of pain in people with diabetes should be further explored.

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).

Protocol for a multicentre, parallel, randomised, controlled trial on the effect of sweeteners and sweetness enhancers on health, obesity and safety in overweight adults and children: the SWEET project

INTRODUCTION

The aim of this randomised controlled trial (RCT) is to investigate whether prolonged consumption of sweeteners and sweetness enhancers (S&SEs) within a healthy diet will improve weight loss maintenance and obesity-related risk factors and affect safety markers compared with sugar.

METHODS AND ANALYSIS

SWEET (S&SEs: prolonged effects on health, obesity and safety) is a 1-year multicentre RCT including at least 330 adults with overweight (18-65 years, body mass index (BMI) >25 kg/m²) and 40 children (6-12 years, BMI-for-age >85th percentile). In an initial 2-month period, adults will consume a low-energy diet with the aim to achieve ≥5% weight loss. Children are advised to consume a generally healthy diet to maintain body weight, thus reducing their BMI-for-age z-score. In the following 10 months, participants will be randomised to follow a healthy ad libitum diet with or without S&SE products. Clinical investigations are scheduled at baseline, after 2, 6 and 12 months. The primary outcomes are body weight for efficacy and gut microbiota composition (in relation to metabolic health) for safety, both in adults. Secondary outcomes include anthropometry, risk markers for type-2 diabetes and cardiovascular diseases, questionnaires including, for example, food preferences, craving and appetite and tests for allergenicity.

ETHICS AND DISSEMINATION

The trial protocol has been approved by the following national ethical committees; The research ethics committees of the capital region (Denmark), approval code: H-19040679, The medical ethics committee of the University Hospital Maastricht and Maastricht University (the Netherlands), approval code: NL70977.068.19/METC19-056s, Research Ethics Committee of the University of Navarra (Spain), approval code: 2019.146 mod1, Research Ethics Committee of Harokopio University (Greece), approval code: 1810/18-06-2019. The trial will be conducted in accordance with the Declaration of Helsinki. Results will be published in international peer-reviewed scientific journals regardless of whether the findings are positive, negative or inconclusive.

TRIAL REGISTRATION NUMBER

NCT04226911 (Clinicaltrials.gov).

Dose-Response and Substitution Analyzes of Sweet Beverage Consumption and Body Weight in Dutch Adults: The Lifelines Cohort Study

Background/Methods

Prospective studies investigating sweet beverages and body weight associations show inconsistent results. Within the SWEET project, we examined prospective dose-response associations of sugar-sweetened beverages (SSB), low/no-calorie beverages (LNCB), and fruit juice with body weight-related outcomes among 78,286 Dutch adults followed for ~4 years. Baseline intakes were assessed using a validated food-frequency questionnaire (FFQ) with 150 ml representing a standard serving. Outcome variables were body weight change, waist circumference change, overweight/obesity, and abdominal obesity. Associations were investigated by using linear and non-linear dose-response analysis, as well as substitution models while adjusting for multiple socio-demographic, lifestyle, health, and dietary variables.

Results

Participants were 46 ± 13 (mean ± SD) years old and 60% were women. Adjusted dose-response analyzes indicated an association between SSB and LNCB, and both body weight (+0.02 kg/year; SE 0.01 and +0.06 kg/year; SE 0.01) and waist circumference changes (+0.04 cm/year; SE: 0.01 and +0.11 cm/year; SE: 0.01). Associations for overweight/obesity and abdominal obesity incidence were +3% (95%CI: 1.00–1.06) and +2% (95%CI: 0.99–1.06) for SSB and +8% (95%CI: 1.06–1.11) and +5% (95%CI: 1.03–1.07) for LNCB, respectively. Substitution of SSB with LNCB was associated with higher weight change (+0.04 kg/year), waist circumference change (+0.09 cm/year), overweight/obesity incidence (+6%), but not abdominal obesity incidence. For fruit juice, we observed beneficial associations for intake levels below ~1 serving/day with weight, waist circumference change, and overweight/obesity incidence, and no association with abdominal obesity. Subsequent substitution analyzes indicated a small beneficial association for the replacement of SSB with fruit juice on weight (−0.04 kg/year) and waist circumference (−0.04 cm/year), but not with other outcomes.

Conclusions

Overall, our results suggest that habitual consumption of both SSB and LNCB may adversely affect weight-related outcomes. In contrast, fruit juice consumption <150 ml may be beneficial with respect to weight and waist circumference.

Is There an Academic Bias against Low-Energy Sweeteners?

This perspective considers evidence of a common academic bias against low-energy sweeteners (LES). The core proposition is that this bias is manifested in research and reporting focused on generating and placing a negative spin on LESs, largely through selective citation, interpretation and reporting. The evidence centres on three inter-related points, which together may generate a misleading impression of the balance of evidence: (1) basic and mechanistic research on LES perpetuates “explanations” for unsubstantiated adverse effects of LES; (2) the literature on LES—particularly narrative reviews and commentaries—continually reprises hypotheses of adverse effects without acknowledging where these hypotheses have been rigorously tested and rejected; and (3) negative interpretations of the effects of LES largely rely upon selectively emphasising lower-quality research whilst ignoring or dismissing higher-quality evidence. The expert community should consider these issues in assuring scientific integrity and balance in the academic discourse on LES, and how this is translated into messages for public health and consumers.

COUNTERPOINT: Artificial Sweeteners for Obesity-Better than Sugary Alternatives; Potentially a Solution

OBJECTIVE

Nonnutritive (NNSs) are used in place of sugars to reduce caloric and glycemic intake while providing desired sweetness, commonly replacing sugar-sweetened beverages (SSBs) with "diet" (zero-calorie) alternatives. Concern has developed due to observational data associating NNSs with obesity and adiposity-based chronic disease. This counterpoint argues that, in general, NNSs used in place of added or excess sugars in the diet are likely beneficial.

METHODS

A literature review was conducted on interventional trials investigating NNSs and obesity or type 2 diabetes mellitus. Key words used in the search included artificial sweeteners, nonnutritive sweeteners, saccharin, sucralose, aspartame, stevia/steviol, acesulfame potassium, meal replacements, type 2 diabetes mellitus, obesity, and weight.

RESULTS

Interventional data and indirect interventional data consistently showed beneficial effects on weight and cardiometabolic health, including glycemia, when SSBs or other energy-dense foods were replaced by artificially sweetened beverages or artificially sweetened meal replacements.

CONCLUSION

Although NNSs correlate with obesity and adiposity-based chronic disease, those data are fraught with confounding and error. Plausibility has been suggested on the basis of preclinical research on neuroendocrine control of appetite, satiety, and cravings plus the gut microbiome. However, interventional data reveal that replacing caloric/glycemic energy intake via NNSs creates an energy deficit resulting in weight loss and improvement in disease-especially dysglycemic disease. Intensive dietary intervention using artificially sweetened meal replacements shows a marked clinical benefit without detriment from their NNSs. Furthermore, beverages sweetened with NNSs rather than SSBs have been noted to be a critical component for those succeeding in maintaining weight loss. Although individual responses to the effects of NNSs are always warranted just like in any clinical situation, patients should not be advised to avoid NNSs in the context of dietary intervention to improve quality and energy deficit.

Gastric emptying of solutions containing the natural sweetener erythritol and effects on gut hormone secretion in humans: A pilot dose-ranging study

AIM

To determine whether a dose-dependent effect in the stimulation of gut hormone release (plasma cholecystokinin [CCK], active glucagon-like peptide-1 [aGLP-1] and peptide tyrosine tyrosine [PYY]) is found for the natural sweetener erythritol.

MATERIALS AND METHODS

Twelve healthy, lean volunteers received solutions with 10, 25 or 50 g erythritol, or tap water enriched with ¹³ C-sodium acetate on four study days via a nasogastric tube in this randomized (active treatments), placebo-controlled, double-blind, cross-over trial. Blood samples and breath samples (¹³ C-sodium acetate method for measurement of gastric emptying [GE]) were taken at regular intervals, and sensations of appetite and gastrointestinal symptoms were rated.

RESULTS

We found (a) a dose-dependent stimulation of CCK, aGLP-1 and PYY, and slowing of GE, (b) no effect on blood glucose, insulin, motilin, glucagon or glucose-dependent insulinotropic polypeptide, (c) no effect on blood lipids and uric acid, and (d) no abdominal pain, nausea or vomiting.

CONCLUSIONS

Solutions with 10 and 50 g of erythritol stimulated gut hormone release. Emptying of erythritol-containing solutions from the stomach was slower compared with placebo. There was no effect on plasma glucose, insulin, glucagon, blood lipids or uric acid. All doses were well tolerated.

Low-calorie sweeteners in the human diet: scientific evidence, recommendations, challenges and future needs. A symposium report from the FENS 2019 conference

Overconsumption of free sugars, particularly from sugar-sweetened beverages (SSB), has potential negative health impacts. Implementation of a range of public health strategies is needed to reduce intakes of free sugars, including reducing portion sizes, promoting healthier dietary choices and reformulating foods and beverages. Although low-calorie sweeteners (LCS) are a useful tool for reducing energy intake and control glucose response when consuming sweet foods and drinks, several opinions persist about the adverse health effects of LCS, many of which are based on poor, little or no scientific evidence. This symposium report summarises key messages of the presentations and related discussions delivered at a scientific symposium at the 13th European Nutrition Conference (FENS 2019). These presentations considered the scientific evidence and current recommendations about the use and potential benefits of LCS for human health, with a particular focus on current evidence in relation to body weight and glycaemic control. Many of the studies to date on LCS have focused on low-calorie sweetened beverages (LCSB); however, the psychological and behavioural factors influencing consumer beliefs and consumption of LCSB need to be further explored. Current recommendations for LCS use are described, including the conclusions from a recent expert consensus report identifying the challenges that remain with LCS research. Finally, existing knowledge gaps and future actions are described, as well as two large ongoing research projects: SWITCH and SWEET.