Independent report

SACN statement on the WHO guideline on non-sugar sweeteners: summary

Published 2 April 2025

Introduction

In the UK, non-sugar sweeteners (NSS) are used to replace sugar in a wide range of food and drinks. Compared to sugar, NSS offer a sweet taste for fewer or no calories.

The Scientific Advisory Committee on Nutrition (SACN) has previously noted that NSS intake in the UK may have increased as a result of UK government actions to reduce population sugar intakes.

In May 2023, the World Health Organization (WHO) published its guideline Use of non-sugar sweeteners. This position statement summarises and reviews the WHO guideline and the supporting evidence. It focuses on whether NSS are effective in the UK context for:

• reducing overweight and obesity
• preventing weight-related noncommunicable diseases (NCDs)
• promoting dental health

SACN has not reviewed the wider health issues considered by the WHO, such as some cancers, chronic kidney disease and neurocognition.

Since foods that contain NSS are considered to be ‘ultra processed foods’ by the NOVA classification, this position statement should be read alongside SACN’s 2025 evidence update on processed foods and health.

Background

UK recommendations on reducing free sugars are based on findings from the 2015 SACN Carbohydrates and health report (see report for definition of ‘free sugars’). SACN concluded that eating less free sugars will lower the risk of:

• tooth decay
• consuming too many calories
• obesity

SACN recommended that population intakes of free sugars should be reduced to no more than 5% of energy.

People are advised to have foods and drinks high in free sugars (such as sugar-sweetened soft drinks) less often and in small amounts. Many drinks contain sugar or NSS. The UK’s Eatwell Guide recommends that people should aim to drink 6 to 8 cups or glasses of fluid a day (that is, water, lower-fat milk and sugar-free drinks, including tea and coffee).

SACN has not previously undertaken a specific risk assessment on NSS.

The WHO guideline defines NSS as “all synthetic and naturally occurring or modified non-nutritive sweeteners that are not classified as sugars”. WHO notes that NSS can also be referred to as:

• high-intensity sweeteners
• low or no-calorie sweeteners
• non-caloric sweeteners
• sugar substitutes

NSS are also sometimes called ‘artificial sweeteners’.

All NSS used in the UK have undergone a rigorous safety assessment by the European Food Safety Authority or UK Food Standards Agency (FSA). The FSA Approved additives and E numbers page lists 22 sweeteners approved for use in Great Britain, 11 of which provide no calories or are low in calories. This includes common NSS such as:

• aspartame
• saccharin
• sucralose
• steviol glycosides (‘stevia’)

Manufacturers are obliged to list NSS in the ingredients of pre-packaged food and drink, but not the amount of NSS.

In the UK, the government has introduced a range of policies to reduce population free sugars intakes following SACN’s recommendations on free sugars. This included the UK’s Soft Drinks Industry Levy for soft drinks containing added sugar. It is unclear if NSS intakes have increased since introducing this policy, because the last survey of intakes (among children) was carried out in 2003. The UK National Diet and Nutrition Survey is not currently designed to assess intakes of NSS. International data suggests that average intakes of NSS for children and adults are below the acceptable daily intakes.

Internationally, dietary recommendations largely focus on reducing sugar consumption and do not mention NSS (including dietary guidelines in Australia, the USA and the Nordic countries). However, some countries’ sugar reduction policies do include NSS, for example some countries in:

• Europe, South America and also parts of the USA and Canada, include NSS in drinks taxes
• Europe, as well as Australia and Brazil, have policies to exclude NSS in schools
• North and South America, the Nordic countries and France include NSS in national food labelling schemes

The WHO guideline and supporting evidence

The WHO guideline includes the following conditional recommendation:

WHO suggests that non-sugar sweeteners (NSS) not be used as a means of achieving weight control or reducing the risk of noncommunicable diseases.

WHO defines conditional recommendations as:

those recommendations for which the WHO guideline development group is less certain that the desirable consequences of implementing the recommendation outweigh the undesirable consequences or when the anticipated net benefits are very small. Therefore, substantive discussion among policy-makers may be required before a conditional recommendation can be adopted as policy.

The WHO guideline also states that the recommendation should be considered alongside wider healthy eating recommendations.

The WHO guideline was supported by a 2022 systematic review and meta-analysis Health effects of the use of non-sugar sweeteners that assessed the health effects of higher intakes compared with lower intakes of NSS.

Review methods and characteristics

The systematic review included randomised controlled trials (RCTs) and prospective cohort studies (PCS) that investigated the effect of, or the association between, any type of NSS and a range of health outcomes. These included:

• measures of body fatness
• cardiovascular disease
• type 2 diabetes
• cancers
• dental caries (tooth decay)
• mortality
• maternal and child outcomes
• behaviours and preferences

PCS were included that compared NSS consumption with no or lower NSS consumption. Trials were included that compared the intervention with any type of sugar, placebo, plain water or no intervention.

Included studies were assessed for risk of bias. The certainty of the included evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework.

Outcomes of interest for this position statement were evaluated in the following study types.

Out of 47 RCTs, outcomes of interest included:

• 39 on adiposity (body fat) measures
• 31 on type 2 diabetes and diabetes intermediate markers
• 25 on cardiovascular diseases
• 2 on dental health
• one on gestational weight gain and risk for excessive gestational weight in pregnant women

Out of 79 PCS, outcomes of interest included:

• 43 on adiposity measures
• 20 on type 2 diabetes and diabetes intermediate markers
• 24 on cardiovascular diseases
• 1 on dental health

Most RCTs compared sugar containing drinks with drinks containing an NSS (most commonly aspartame, followed by sucralose and stevia). Most of the RCTs were conducted in adults, the majority of which lasted less than 3 months.

Most PCS considered adult exposure to NSS as part of a drink. Follow-up in adults ranged from 2 years to more than 30 years.

Main findings

The systematic review reports conflicting evidence on the impact of NSS based on the type of evidence assessed.

RCT data was available for adiposity outcomes and NCD outcomes were largely only considered by PCS.

The RCT data indicated that NSS may result in a small reduction in body weight based on low certainty evidence. But PCS evidence indicated that higher NSS intake was associated with higher measures of body fatness in adults and children based on low to very low certainty evidence. The PCS data also indicated that NSS may be associated with a broad range of adverse health outcomes (including type 2 diabetes, cardiovascular diseases and mortality in adults) based on low to very low certainty evidence.

There was limited evidence on dental health outcomes in children and adults.

WHO conclusions

The WHO guideline notes the “discordant results” between the RCT and PCS evidence and states that these:

suggest that the small amount of weight loss resulting from NSS use in short-term experimental settings may not be relevant to the effects of long-term NSS use in the general population.

WHO prioritises the longer-term evidence from PCS over the short-term evidence from RCTs. The rationale was that most RCTs assessing NSS lasted 3 months or less and there were inconsistent results from those lasting more than 3 months.

The WHO guideline interprets the systematic review findings as:

no evidence of long-term benefit on measures of body fatness in adults or children, and, from observational evidence, potential undesirable effects from long-term use in the form of increased risk of type 2 diabetes, CVDs and mortality in adults.

SACN’s assessment

SACN considered the differences between the methods of evidence evaluation adopted in the systematic review that underpinned the WHO guideline and the SACN ‘Framework for the evaluation of evidence’ (for more information on the framework, see the SACN webpage).

WHO gave greater weight to PCS evidence over RCT evidence in reaching conclusions for this guideline. Notably, SACN gives greater weight to good quality RCTs, where available, because these minimise the potential for bias and confounding (factors that are related to both NSS consumption and the health outcomes being considered).

Randomisation is particularly important when looking at weight outcomes given that NSS use is potentially confounded by weight and associations with diet. In this case, SACN would give greater weight to the evidence from RCTs. That is, that NSS use in place of sugars resulted in a small reduction in body weight and body mass index scores in adults. Although, SACN notes that the effect size is small and limited by the length of the trials (most were 3 months or less).

WHO considered that the shorter-term RCTs were not long enough to be able to determine the impact on weight loss. SACN notes that there may be a health benefit from short-term weight loss even if there is subsequent weight gain. SACN notes that one RCT lasted longer than 2 years and reported a greater reduction in body weight (around 5kg compared to less than 1kg in shorter-term RCTs). The association remained when studies of less than 8 weeks were excluded.

Observational studies such as PCS are at high risk of ‘reverse causality’ and confounding, which are likely to have contributed to the differences between observational and trial evidence. For example, people may have chosen to consume NSS sweetened foods and drinks because of their weight, rather than NSS causing weight gain. Also, consuming NSS foods and drinks may be linked to other factors known to effect health such as socioeconomic status, smoking or alcohol. SACN welcomes the detailed list of confounders adjusted for in the PCS. However, the systematic review authors do not fully acknowledge the possibility of confounding that could not be accounted for.

SACN notes that it may have come to different conclusions to the systematic review on the application of GRADE and the certainty of the evidence.

SACN notes that WHO issued a conditional guideline that NSS should not be used as a means of achieving weight control or reducing risk of NCDs. This was due to uncertainties of the evidence.

SACN’s conclusions

Body fatness

SACN concludes that evidence from shorter and longer-term RCTs consistently suggest NSS, compared with free sugars, reduce energy intake and therefore body weight, although WHO assesses this as low certainty evidence.

The opposite association was found between NSS and measures of body fatness in PCS (that is, NSS may increase weight gain in people not taking part in a trial). Given concerns about potential for confounding and reverse causality in PCS, SACN would give less weight to this evidence and concludes this evidence should be treated with caution. However, SACN notes the potential for PCS evidence to provide an insight into how people consume foods and drinks containing NSS in a real-life setting.

Noncommunicable diseases

SACN shares WHO’s concerns regarding the risks of NCDs associated with NSS intake given the range of studies observing such associations. However, relying on observational data and limited data from RCTs prevents the drawing of robust conclusions. SACN concludes that while the evidence on NCDs is concerning it should be treated with caution. SACN would welcome further, more robust, long-term evidence, particularly from RCTs, to explore any association and the possible underlying mechanisms.

Dental caries

The evidence on the impact of consuming NSS on dental health is poor and more high-quality research of adequate duration (greater than 2 years) is needed to determine long-term impact. Given the current low and very low certainty evidence, SACN determines that it is difficult to draw conclusions regarding NSS and dental health from this review. However, SACN notes that the use of NSS in food and drink may support lowering the intake of free sugars and thereby dental caries. Although replacing free sugars with NSS is not essential to achieve this, it may be a useful option for some people.

Dietary recommendations

SACN and WHO agree that a reduction in consumption of free sugars, alongside other positive changes to diet, is likely to be beneficial to health overall. The risk management decision on how to achieve a reduction in intake of free sugars is outside of SACN’s remit and is for policy makers.

In relation to the use of NSS to reduce free sugars intake, SACN concludes that the evidence indicates that there may be some value in using NSS to help reduce weight gain in the short to medium term, but it is not essential and is not the only option.

SACN reiterates the importance of following UK government advice on a healthier diet, based on SACN’s recommendations, which is summarised in the UK’s national food guide, the Eatwell Guide.

SACN notes its previously stated concerns about the gap in data on UK population exposure to NSS.

There is currently insufficient evidence to carry out a full risk assessment of the evidence on NSS and health.

SACN’s recommendations

The following recommendations are made in the context of existing UK government dietary recommendations. These recommendations should be read alongside SACN’s 2025 evidence update on processed foods and health. SACN’s recommendations on NSS are precautionary. This is because evidence on NSS and health outcomes is inconsistent.

SACN reiterates its recommendation that average population intake of free sugars should not exceed 5% of energy.

SACN recommends that intake of NSS be minimised.

For younger children, SACN recommends:

• not giving them drinks sweetened with sugar or NSS
• giving them unsweetened food (not sweetened with either sugar or NSS)

For older children and adults, SACN recommends:

• swapping sugars for NSS may help reduce sugar intake from foods and drinks (and so reduce energy intake), at least in the short term - the long-term goal is to limit both sugar and NSS intake

It is recommended that government:

• monitors the NSS content of food and drinks in the UK diet and their consumption, including trends, particularly among high consuming and vulnerable groups
• evaluates the impact of policies to reduce energy and sugar intakes on intakes of NSS, particularly among high consuming and vulnerable groups
• compels industry to make publicly available data on the amounts of individual NSS within foods to enable monitoring and further research on associations with health outcomes

SACN also made a range of research recommendations. This includes conducting research that:

• addresses concerns relating to confounding between NSS and health outcomes
• considers vulnerable groups (including high consumers, young children and pregnant or lactating women)
• explores innovative ways to reliably monitor exposure to NSS