WHO advises against non-sugar sweeteners for weight control, experts flag scientific limitations

17 May 2023 --- The World Health Organization (WHO) has stated long-term use of non-sugar sweeteners (NSS) does not have long-term benefits in reducing body weight and may have undesirable effects, such as the risk of type 2 diabetes, cardiovascular diseases and premature mortality in adults. However, some experts find the supporting evidence insufficient.

“What we hope to achieve with this guideline and other existing and forthcoming guidelines on healthy diets is an overall improvement of dietary quality,” Jason Montez, a scientist in the Department of Nutrition and Food Safety at the WHO, tells NutritionInsight.

“The guideline is based on a systematic review of the scientific literature published in 2022, including more than 280 studies. The guideline and the recommendation contained within were developed following the WHO guideline development process, which is a rigorous, structured and transparent process and is described in detail in the guideline.” 

The new guidance includes all synthetic, naturally occurring or modified non-nutritive sweeteners not classified as sugars, found in manufactured F&B or sold independently. Common NSS include acesulfame K, aspartame, advantame, cyclamates, neotame, saccharin, sucralose, stevia and its derivatives. 

Vicky Pyrogianni, Nutrition Science director at the International Sweeteners Association (ISA) tells us that the "WHO recommendation is inconsistent with the global integrated approach to addressing noncommunicable diseases to which WHO and its Member States have committed, of which sugar reduction reformulation of foods and drinks is an integral part."

Non-sugar sweeteners include acesulfame K, aspartame, advantame, cyclamates, neotame, saccharin, sucralose and stevia."There is no scientific evidence to support avoiding their use and, crucially, they are already playing an essential role in helping food and drink companies reduce or eliminate the amount of sugar in their products." 

Conditional recommendation 
The guideline is aimed at policymakers, program managers, health professionals and other stakeholders. 

The WHO has set the recommendation as conditional, meaning that policy decisions may require considerable discussion in specific country contexts since it recognizes that baseline characteristics of study participants might confound the observed link between NSS and disease outcomes.

“The risk for bias and quality of the studies included in the review were explicitly assessed using established frameworks. Overall, most studies, including randomly-controlled trials (RCT), were of low or very low certainty, with only a few of moderate or higher certainty,” comments Nita Forouhi from the MRC Epidemiology Unity at the University of Cambridge, UK. 

“The most critical issue is the ‘how’ factor. Translating the guideline into action will require concerted action from many players, including policymakers, public health agencies and food manufacturers, which ultimately also require a degree of behavior change by individuals,” adds Forouhi. 

Reducing sugar intake 
The new guideline does not apply to personal care and hygiene products containing NSS – such as toothpaste, skin cream and medications – or low-calorie sugar and sugar alcohols, which are not considered NSS. It also does not apply to individuals with pre-existing diabetes. 

“With the NSS guideline (and the 2015 free sugars guideline), we hope to communicate that free sugars intake can and should be reduced (where intake is high) without the use of NSS,” adds Montez. 

“This can be achieved by replacing free sugars in the diet with sources of naturally occurring sweetness, such as fruits, as well as minimally processed unsweetened foods and beverages, lowering the overall sweetness of the diet where needed.”

The recommendation is conditional so that policy decisions may require considerable discussion in specific country contexts.Montez continues, “Updated guidance on total fat intake, saturated fat, trans-fat and carbohydrates will be released in the coming weeks. We plan to look next at certain food groups and the level of processing of foods and beverages.”

To reduce sugar cravings, food tech start-up Sweet Victory developed a botanical chewing gum that blocks the sweet taste receptor in the tongue, landing the company an innovation award at the recent Vitafoods Europe trade show. 

A different innovation comes from Israeli-based food tech company DouxMatok, which produces a sugar-based sugar reduction solution that manufacturers can use to reduce sugar content by 30 to 50% without sweeteners. 

Short-term benefits 
As evidence supports the role of non-sugar sweeteners in reducing calories in the short term, it can be part of interventions to manage weight, notes Forouhi. 

“The duration of most of the RCTs was very short, mostly a couple of weeks or under three months, while very few were longer than six months and of around 50 RCTs, only five were of one year or longer duration.” 

Although replacing sugar with sweeteners alone is unlikely to improve diet quality and produce necessary changes to control weight long term, it may be a way to reduce overall sugar intake for some people, notes Dr. Duane Mellor, dietitian and lecturer at Aston University, UK. 

“The report focuses heavily on the observational studies which can only show an association between non-sugar sweeteners and a health outcome, in this case largely weight control, rather than clinical trials which are better at showing causal links.”  

Researchers indicate that the scientific evidence for the guidance was of low or very low certainty, with limited proven causal links.“In the case of sweeteners, several trials have shown that they can help with weight control, whereas observational studies may not show an association between sweeteners and weight control.” 

Industry response 
The ISA aims to work with the WHO to ensure the benefits of low and no calorie sweeteners are fully understood, adds Pyrogianni.  

"Low and no calorie sweeteners enable food and beverage companies to reformulate products to contain less sugar and fewer calories, ultimately supporting public health objectives – including from the WHO – to reduce sugar and calorie consumption," she continues. 

"Low or no calorie sweeteners are safe to use, one of the most thoroughly researched ingredients in the world and have been approved by all major food safety authorities. They also assist with weight management by allowing consumers to enjoy food and drinks that have less sugar and fewer calories, while still meeting taste preferences."

“In my opinion, this advice is likely to cause a lot of confusion in the public health arena because the sugar levy in the UK has drinks manufacturers replacing some or all of the sugar with artificial sweeteners,” concludes Tom Sanders, professor emeritus of Nutrition and Dietetics at King’s College London, UK. 

Last year, sugar industry members flagged that sugar reduction guidance by the European Food Safety Authority could lead to an increase in artificial sweeteners. 

By Jolanda van Hal