Statement on WHO non-sugar sweeteners guideline

The World Health Organisation (WHO) has published a new guideline document on the use of non-sugar sweeteners. This provides guidance on the use of non-sugar sweeteners to reduce the risk of unhealthy weight gain and diet-related noncommunicable diseases in adults and children, based on a systematic review of the available evidence.

The guideline advises that non-sugar sweeteners should not be used for weight control. The systematic review that underpins this recommendation found a lack of evidence that such sweeteners benefit weight loss in the long term (although benefits were seen in some short-term studies) and highlighted the possibility of negative effects on health including an increased risk of type 2 diabetes, cardiovascular diseases, and mortality in adults. Rather than using non-sugar sweeteners the WHO advises that people need to consider other ways to reduce free sugars intake, such as consuming foods with naturally occurring sugars, like fruit, or unsweetened foods and beverages.

The recommendation applies to all people except individuals with pre-existing diabetes and includes all synthetic and naturally occurring or modified non-nutritive sweeteners that are not classified as sugars found in manufactured foods and beverages or sold on their own to be added to foods and beverages by consumers, such as acesulfame K, aspartame, advantame, cyclamates, neotame, saccharin, sucralose, stevia and stevia derivatives.

The recommendation is classed as ‘conditional’ (as opposed to ‘strong’) because of uncertainty over the balance of risk vs benefits of non-sugar sweeteners, and it is based on evidence that WHO classified as ‘low certainty’ overall. While it is certainly desirable that people make significant changes to their diets to reduce free sugars, we know that it is very challenging to make this happen in practice. A lot of work has been done in the UK, particularly with drinks, to replace some or all sugars with non-sugar sweeteners in an effort to nudge people towards lower free sugars intakes. This can be part a range of different policy actions to encourage lower intakes of free sugars. Considering the conditional nature of the recommendation and the fact that all the sweeteners in our food supply have been rigorously tested for safety, it seems sensible to continue to make use of all the tools at our disposal to improve people’s diets.

The guidance document can be found here: https://www.who.int/publications/i/item/9789240073616

The accompanying press release here: https://www.who.int/news/item/15-05-2023-who-advises-not-to-use-non-sugar-sweeteners-for-weight-control-in-newly-released-guideline

The evidence

• Evidence from a recent systematic review and meta-analyses of randomized controlled trials (RCTs) and prospective observational studies found that higher non-sugar sweetener (NSS) consumption by adults led to lower body weight and body mass index (BMI), compared with not consuming NSS or consuming lower amounts of NSS, when assessed in short-term RCTs, but was associated with increased BMI and risk of incident obesity in long-term prospective observational studies.
• Effects on body weight and BMI from RCTs are observed only when intake of NSS is compared with intake of free sugars, and are likely mediated at least in part by a reduction in energy intake. No other significant effects or associations on measures of body fatness were observed in either RCTs or prospective cohort studies.
• Long-term NSS use was associated with increased risk of type 2 diabetes, cardiovascular diseases (CVDs) and mortality in prospective cohort studies conducted in adults. However, significant effects were not observed on intermediate markers of disease such as fasting glucose, fasting insulin or blood lipids when assessed in short-term RCTs.
• Evidence from studies conducted in children and pregnant women was more limited than that identified for adults. One RCT conducted in children reported a reduction in several measures of body fatness when sugar-sweetened beverages were replaced with beverages containing NSS; however, no effect was observed when results for BMI z-score2 were combined with those from a second trial.
• Results from prospective observational studies did not suggest any significant associations between NSS use and measures of body fatness. Two RCTs conducted in children reported lower indicators of dental caries with use of the NSS stevia.
• All other identified studies reported no significant associations between NSS use and prioritised health outcomes in children. Meta-analysis of three prospective observational studies found an increased risk of preterm birth with higher NSS use during pregnancy, but associations observed between birth weight or weight of offspring later in life and NSS use during pregnancy were inconsistent.
• Single prospective observational studies reported associations between NSS use during pregnancy and outcomes in offspring, including increased risk of asthma and allergies, and poorer cognitive function.