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.

The term ‘sweeteners’ encompasses both nutritive and non-nutritive sweeteners, which when added to food/beverages, can enhance the flavour and other functional properties of food/beverage products. This review considers how dietary biomarker approaches may enhance current understanding of nutritive sweetener (namely free sugars) and non-nutritive or low-energy sweetener (LES) intakes and how these may impact health. Recent public health strategies to reduce free sugar consumption will help contribute to challenging sugar intake targets. Robust evaluation is needed to determine the effectiveness of these approaches to reducing free sugar consumption. LES provides a sweet taste without the addition of appreciable energy and can help maintain the palatability of reformulated products. All LES undergo rigorous safety evaluations prior to approval for use. Whilst intervention data suggest LES can be beneficial for health (relating to weight status and glycaemic control), debate persists on their use and findings from population-based research are mixed, in part because of potential contributing factors such as reverse causality. Additionally, assessments often consider only certain sources of LES (e.g. LES-beverages) and/or LES as a homogeneous group despite differing biological fates, thus not adequately capturing intakes of individual LES or allowing for reliable estimation of overall intakes. Urinary biomarker approaches developed/investigated for sweetener consumption have the potential to overcome existing limitations of dietary data by providing more objective intake data, thereby enhancing population-based research. In conclusion, such biomarker approaches to the concomitant study of free sugars and LES intakes are timely and represent interesting developments in an area of significant public health interest.

Low-calorie sweeteners (LCS) are commonly used as sugar substitutes in the diet to provide a desired sweet taste without increased energy intake. The number of LCS available on the market has increased considerably over the years and despite extensive evaluation of their safety prior to approval, debate continues around the effects of consumption on health. In Europe, Member States are obligated to monitor exposure to LCS and methods currently used tend to rely on self-reported dietary intake data alongside LCS concentrations in products. However, the acquisition of accurate data can be costly in terms of resources and time and are inherently imprecise. Although LCS are intensely sweet, they are chemically diverse and a limitation of many studies investigating the health effects of consumption is that they often fail to discern intakes of individual LCS. An approach which objectively assesses intakes of individual LCS would therefore allow robust investigations of their possible effects on health. Biomarker approaches have been utilised for the objective investigation of intakes of a range of dietary components and the feasibility of any such approach depends upon its validity as well as its applicability within the target population. This review aims to provide an overview of current understanding of LCS intake and explore the possibility of implementing a biomarker approach to enhance such understanding. Several commonly used LCS, once absorbed into the body, are excreted via the kidneys; therefore a urinary biomarker approach may be possible for the investigation of short-term exposure to these compounds.