Highlights include recommendations, new research and scientific events
- European and American clinical practice guidelines published in 2023 support the use of low/no calorie sweeteners in place of sugars, contrary to what WHO suggests in a conditional recommendation
- New long-term clinical studies indicate benefits of low/no calorie sweeteners in weight loss and maintenance
- The safety of aspartame, as for all approved low/no calorie sweeteners, is confirmed by food safety bodies around the world including the Joint FAO/WHO Expert Committee on Food Additives (JECFA)
This year’s headlines caused a lot of confusion about the role of low/no calorie sweeteners led primarily by conflicting clinical practice guidelines and nutrition recommendations. The present article provides an overview of guidelines and reports published in 2023, a summary of key scientific studies, and science news from ISA-supported scientific events.
Conflicting clinical practice and nutrition recommendations
A new guideline issued by the World Health Organization (WHO) in May 2023 suggested non-sugar sweeteners not to be used as a means to achieve weight control (a conditional recommendation)1, at the same time that American and European recommendations for the nutritional management of diabetes supported the use of low/no calorie sweeteners in place of sugar as a way to help reduce overall calorie and carbohydrate intake, and thus assist in weight management and glucose control.2,3 These conflicting recommendations led to confusion among the public but also within the scientific and health professionals communities.
The WHO conditional (or else weak) recommendation relied largely on observational studies that are inherently limited by reverse causality and residual confounding.4,5 The greater weight given to observational studies over randomised controlled trials (RCTs) and discounting evidence from prospective cohort studies which applied methodologies to reduce bias was criticised in the scientific literature.4 Academic experts stress that these issues limit the usefulness of the guideline and/or call for additional research to inform conclusive recommendations for sweeteners use.4,5
Evidence-based recommendations for the dietary management of diabetes
New clinical practice guidelines for the nutritional management of diabetes have been issued by the Diabetes and Nutrition Study Group (DNSG) of the European Association for the Study of Diabetes (EASD) in April 20232 and by the American Diabetes Association in January 20233, respectively. Both organisations supported the use of low/no calorie sweeteners in place of sugars as a means to help reduce overall calorie and carbohydrate intake as long as there is not a compensatory increase in energy intake from other sources.
Evidence from newly published systematic reviews
Several systematic reviews looking at health effects of low/no calorie sweeteners have been published this year. Results of a meta-analysis of RCTs byTobiassen et al showed that replacing habitual sugar-sweetened beverage consumption with low/no calorie sweetened beverages or water resulted in a small but significant long-term reduction of body mass index (BMI).7 A trend towards a larger BMI reduction in interventions of longer duration (>12 months) was also found. Similarly, a systematic review and meta-analysis of RCTs in children showed that low/no calorie sweetener intake versus sugar resulted in less BMI gain in adolescents and children/ adolescents with obesity.8 Generally, meta-analyses of RCTs consistently report a beneficial effect of low/no calorie sweeteners’ use on weight control and cardiometabolic health, while observational studies suggest a positive association with higher risk of obesity or other chronic cardiometabolic diseases. Espinosa and colleagues call for more long-term prospective analyses with changes in repeated measures to help provide more accurate associations in observational studies.8
Khan and colleagues compared results of meta-analyses of prospective cohort studies using only one single sweetener exposure assessment at baseline with findings of prospetive cohorts with repeated measures that allow for change and substitution analysis.4 They found that the change and substitution analysis showed a neutral or even protective association between low/no calorie sweeteners and cardiometabolic diseases, in contrast to the harmful association shown by the studies with single analysis. The authors reminded that the conditional recommendation of the WHO guideline relied solely on evidence from prospective cohort studies with single baseline assessments of low/no calorie sweeteners without considering change and substitution analysis or RCT data that both support a useful role for low/no calorie sweeteners.4 The consistency between trial results and analytically rigorous prospective cohort studies warrants a reconsideration of the WHO’s evidence base and recommendation.
Benefits of low/no calorie sweeteners in long-term weight control confirmed in new large clinical studies
Preliminary findings from the long-term clinical trial of the Horizon 2020 SWEET project that were presented at the 14th European Nutrition Conference – FENS 2023 indicate a modest but significant benefit of low/no calorie sweeteners’ use in long-term weight control. Similarly, results from the just published SWITCH study, a long-term randomised controlled trial in 493 adults living with overweight or obesity, showed a modest but significantly greater weight loss maintenance with low/no calorie sweetened drinks compared with water after following a one-year weight loss and weight maintenance programme.6
Aspartame’s safety reconfirmed by WHO/FAO JECFA
On 14th July 2023, the Joint Food and Agriculture Organisation (FAO)/ WHO Expert Committee on Food Additives (JECFA) re-affirmed the safety of aspartame and re-confirmed the Acceptable Daily Intake (ADI) of 40 mg/kg body weight.9
Following review of an extensive evidence base, JECFA concluded that there was no convincing evidence from experimental animal or human data that aspartame has adverse effects after ingestion.9 JECFA also evaluated carcinogenic potential including the outcome of a review by a working group of the International Agency for Research on Cancer (IARC), concluding that there was “no concern for carcinogenicity in animals from oral exposure to aspartame,” and that the “evidence of an association between aspartame consumption and cancer in humans is not convincing”.10
Earlier this year, a comprehensive quantitative review of toxicological and epidemiological data on the relation between approved low/no calorie sweeteners, including aspartame, and cancer concluded that there is no evidence of cancer risk associated with low/no calorie sweeteners’ consumption.11
We hope you enjoyed reading the 2023 year-in-review article. The ISA’s mission is to provide healthcare professionals, researchers, regulatory bodies, policy makers, the media and consumers with science-based information to support public understanding of the safety and benefits of low/no calorie sweeteners, and we will continue to do so next year.
We wish you a happy New Year!