Member Matters

Newly released UK nutrition expert report on the role of non-sugar sweeteners

16 April 2025

Early this month, the UK Scientific Advisory Committee on Nutrition (SACN) published Statement on the WHO guideline on non-sugar sweeteners: summary.

In the UK, as elsewhere in the world, non-sugar sweeteners (NSS) have gained popularity as substitutes for sugar in various foods and beverages. Their appeal lies in the ability to provide sweetness without the associated energy (kilojoules) of sugar. This rise in NSS consumption aligns with government initiatives aimed at reducing overall sugar intake among the population. A key reference point for understanding NSS usage is the World Health Organization (WHO), which published guidelines in May 2023 that evaluate the role of NSS in addressing health concerns associated with sugar consumption.  

The SACN examined the methodologies used in the systematic review supporting the WHO guidelines on NSS. SACN noted that WHO prioritised primary cohort studies (PCS) over randomised controlled trials (RCTs) when concluding that NSS are not effective for weight control or reducing the risk of noncommunicable diseases (NCDs). In contrast, SACN emphasised the significance of high-quality RCTs, which minimise bias and confounding factors that might affect the outcomes related to NSS intake and weight. 

SACN argued that because weight outcomes can be influenced by confounding factors—such as people may have chosen to consume NSS sweetened foods and drinks because of their weight—evidence from RCTs is more trustworthy. While some RCTs indicated that replacing sugars with NSS could lead to modest reductions in body weight, the effect sizes were small, and the trials were generally short (mostly under three months). SACN also highlighted a longer-term RCT that indicated a more substantial weight reduction, approximately 5 kg over two years, suggesting that prolonged NSS use may have potential benefits. 

Despite concerns regarding reverse causality in observational studies, where individuals may choose NSS due to pre-existing weight issues, SACN recognised that these studies could still offer valuable insights into real-world consumption patterns of NSS. At the same time, SACN was cautious about the evidence suggesting NSS might be associated with weight gain due to the possibility of confounding factors. 

Regarding NCDs, SACN concurred with WHO’s position regarding risks associated with NSS intake but cautioned against drawing firm conclusions based on the observational data and limited RCTs available. The committee called for more robust research to better understand any potential links and mechanisms between NSS and NCDs. 

In relation to dental health, SACN found existing evidence on NSS ineffectual and acknowledged the need for high-quality studies lasting over two years to ascertain long-term impacts. While replacing free sugars with NSS may help reduce sugar intake and dental caries, SACN maintained that this method is not essential. 

Both SACN and WHO agree on the benefits of reducing free sugar consumption alongside positive dietary changes. SACN highlighted that NSS could play a role in helping manage weight in the short to medium term, but it is not the sole solution. Lastly, SACN emphasised adherence to UK government dietary guidelines derived from their recommendations. 

The SACN recommendations regarding NSS in the context of UK dietary guidelines are precautionary due to inconsistent evidence linking NSS to health outcomes. They emphasise that average free sugar intake should not exceed 5% of energy and suggest minimising NSS consumption. 

For younger children, it is advised to avoid both sugar and NSS in drinks and to provide unsweetened foods. For older children and adults, swapping sugars for NSS may help reduce overall sugar intake in the short term, but long-term goals should aim to limit both sugars and NSS.  

The committee urged the UK government to monitor NSS in the food supply, evaluate policies on sugar intake, and require industry transparency regarding NSS levels. Additionally, SACN calls for research to address confounding factors linking NSS to health outcomes and to focus on vulnerable groups, including high consumers and young children.