Hitting the sweet spot23 December 2021
Low-calorie sweeteners (LCS) are marketed as an integral part of weight loss plans, but their impact on weight maintenance and on conditions such as diabetes is still relatively underexplored. Ingredients Insight presents an abridged version of a paper derived from a consensus workshop entitled ‘The science behind low calorie sweeteners: where evidence meets policy’ to assist health practitioners and policy makers to promote consistent messages and develop strategies based on sound science.
This paper describes the results of a workshop in which seventeen experts convened to discuss and debate the science and policy relating to the use of LCS. The aims were to establish clear and simple statements on LCS that all the panel agreed on, to highlight the areas where more research is required, and to propose how progress might be achieved. They discussed three themes identified as key to the science and policy of LCS: (1) weight management and glucose control; (2) consumption, safety and perception; (3) nutrition policy. The panel agreed that the safety of LCS is demonstrated by a substantial body of evidence reviewed by regulatory experts and current levels of consumption, even for high users, are within agreed safety margins.
However, better risk communication is needed. More emphasis is required on the role of LCS in helping individuals reduce their sugar and energy intake, which is a public health priority. The panel concluded that LCS can be beneficial for weight management when they are used to replace sugar in products consumed in the diet.
The available evidence suggests no grounds for concerns about the adverse effects of LCS on sweet preference, appetite or glucose control. Indeed, LCS may improve diabetic control and dietary compliance. Regarding effects on the human gut microbiota, data is limited and does not provide adequate evidence that LCS affect gut health at doses relevant to human use. The panel identified research priorities, including collation of the totality of evidence on LCS and body weight control, monitoring and modelling of LCS intakes, impacts on sugar reduction and diet quality, and developing effective communication strategies to foster informed choices. There is also a need to reconcile policy discrepancies between organisations and reduce regulatory hurdles that impede low-energy product development and reformulation.
The role of LCS
Members agreed that when substituted for sugars to reduce energy density of foods and drinks, LCS reduce net energy intake and assist weight management. Intervention studies have also shown that beverages containing LCS have at least a similar effect on appetite and energy intake to water. The collective evidence supports the conclusion that LCS have no adverse effect on blood glucose and insulin regulation in individuals with, and without, diabetes. In addition, the potential value of LCS in dietary management of diabetes derives from their role as substitutes for sugars, and hence carbohydrates. Regarding effects involving the human gut microbiota, data is limited.
Lesser known are the long-term effects of LCS on glucose tolerance, gut function, cardiometabolic effects, gut microbiota and weight management. Alongside this, little is known about how and why these effects alter according to personal factors, such as age, sex, ethnicity, socio-economic status, health status, diet and lifestyle. An additional query is whether reducing exposure to sweetness has consequences for food choice and intake in the medium to long-term, and whether LCS can help improve long-term type two diabetes management.
In response to these findings, it was agreed that there is a need for a portfolio of well-designed, randomised, year-long controlled trials with different comparators and different carriers of LCS. The trials should be conducted by the level of ‘free sugar’ intake in different populations, and they should use multiple endpoints (diet quality, gut microbiota function and metabolomics, and wider health and quality of life measures). They should be done in the context of weight-control diets, including for type two diabetes and also in non-restrictive diets. There is also a need for population cohort studies to model changes in weight/cardiometabolic risk in the context of changes in LCS consumption, not baseline LCS values. Data should be made available for further analysis.
Consumption and consumer perception
The consensus was that the safety of LCS is demonstrated by a substantial body of evidence, as well as the continued review by independent regulatory agencies and committees, including JECFA/Codex, FDA and EFSA. These organisations have taken into account decades of both positive and negative human and animal studies to draw their conclusions. Continual monitoring and modelling of LCS exposures is undertaken and this demonstrates that intakes of LCS, even among high consumers, are within ADI.
It was also apparent that the major sources of LCS in the Western diet are beverages and table-top sweeteners, and that LCS can be used to reduce the sugar and energy content of beverages and some foods while maintaining a similar sensory profile. Moreover, consumer perceptions clearly vary with regard to LCS, with some individuals having concerns about their potential health effects.
What is still relatively unclear is which factors influence consumer perception of risks and benefits of LCS consumption. Are these the same for health professionals? To counter this, there is a need for in-depth data relating to current patterns of LCS consumption at multiple levels, and across countries and regions. There is also a need for more reliable measures of LCS exposure, such as biomarkers. Further development of these and better linkage of food composition and dietary databases are needed to help monitor changing use and consumption of LCS.
There is a need to research and develop evidence-based strategies to communicate all of the above to consumers, health professionals and policy makers. The extensive body of scientific evidence that backs regulatory approval and the ongoing safety assessment of LCS can then encourage better-informed public health decisions. Invariably this requires better communications designed to foster more informed public attitudes towards LCS, for example, by emphasising the potential health gains associated with sugar (and energy) intake reduction and the role of LCS in achieving this. It is important to explain that the overall impact of LCS will depend on the amount of sugars replaced in the diet and the overall reduction in calorie (energy) intake that ensues. Use of LCS alone cannot be expected to act as a ‘silver bullet’ for weight loss.
It was agreed that reducing the intake of ‘free sugars’ and ‘added sugars’ is being recommended around the world to lower the risk and prevalence of obesity, which is a major public health concern. LCS are one of the strategies to consider, meanwhile, it can also be useful in dietary approaches to both prevent and manage diabetes. Despite repeated and consistent reassurances from food safety authorities, there is still some distrust of LCS among health professionals and policy makers. Some policies acknowledge LCS consumption as a useful strategy to reduce sugar intakes, however, there are discrepancies with other national and international policies and regarding use in children. In relation to these findings, it is still unclear whether LCS can help individuals meet the population-level dietary recommendations for reduction of sugars intake and how this might be achieved. Moreover, how does a dietary approach that includes LCS-sweetened food and drinks affect dietary quality compared with low-sugar diets, and what are the best strategies to communicate LCS safety and efficacy to interested parties such as health professionals and the general public?
To resolve these quandaries, the panel suggests that there is a need to model the potential for LCS to reduce sugar content and sugar intakes while ensuring that other dietary recommendations can also be met in the overall diet. Trends in dietary intake of LCS need to be monitored, linked with food and beverage reformulation and ultimately with health outcomes. Simultaneously, policies relating to LCS from different countries should be reviewed to compare their remit, priorities, evidence base and interpretation. To reconcile policy discrepancies, policy makers, scientists and regulatory affairs experts should agree on their understanding of the role of LCS in the diet. Finally, in the context of sugar reduction and obesity, it would be helpful to review the regulatory and public health policy hurdles that prevent wider use of LCS in food products for those sweeteners where dietary intake is very low compared with the ADI.
Extending the consensus
Our consensus workshop was designed to stimulate forward thinking, as well as to restate principles. The consensus statements on actions put the focus firmly on what is required to deliver. For example, the panel made recommendations for further long-term randomised controlled trials of LCS with different comparators and multiple endpoints, for prospective studies that control for obesity and other confounders, and for better estimates of LCS exposure. Such recommendations may help research funding bodies select priorities. Clarity and consistency of policy would be improved by a comprehensive evaluation of all the evidence on effects of LCS.
Our expert panel argues that there is a continued need for ongoing exposure assessment to account for changing LCS use, and also consideration of any new evidence that might emerge. Novel recommendations made by the panel included better strategies and methods to improve communications about the safety and efficacy of LCS, modelling of the effect of LCS on sugar reduction and diet quality, relaxing regulation to increase the potential for reformulation using LCS, and review and reconciliation of policy differences on the use of LCS.
LCS in summary
The panel considered that the substantial body of evidence concerning LCS safety should be communicated in a consistent manner. More emphasis is required on the role of LCS in helping individuals reduce their sugar and energy intake, which is a public health priority. Research priorities should include the compilation of a dossier of the totality of evidence on LCS and body weight control; studies to monitor and model LCS intakes and their impact on sugar reduction and diet quality; effective communication strategies to inform consumers, non-governmental organisations (NGOs), health professionals, research funding bodies and the food and beverage industry.
Greater efforts should be made to understand and reconcile policy discrepancies between organisations and reduce regulatory hurdles that impede product development and reformulation designed to reduce sugars and/or energy.