The World Health Organization (WHO) has released a new guideline on non-sugar sweeteners (NSS).
Prof Nita Forouhi, MRC Epidemiology Unit, University of Cambridge, said:
“The findings of the WHO report are justifiable for general populations of people without diabetes, based on the inclusion of all eligible evidence from multiple research study designs, but are limited by several factors, many of which the report acknowledged. Notably, the WHO recommendation on avoiding the use of non-sugar sweeteners for longer term weight management or chronic disease prevention is conditional, therefore context and country specific policy decisions may be needed rather than necessarily being universally implemented as they stand. The role of non-sugar sweeteners as a way to reduce calories in the short-term is, however, supported by evidence – so using sweeteners can be part of interventions to manage weight in the short term.
“The risk for bias and quality of the studies included in the review were explicitly assessed using established frameworks. Overall, the majority of studies, including RCTs, were of low or very low certainty, with only a few of moderate or higher certainty. Also, the duration of most of the RCTs was very short, mostly a couple of weeks or under 3 months, while very few were longer than six months and of around 50 RCTs, only five were of one year or longer duration. These are challenges to the research community to improve upon. Moreover, research specifically focused on people with diabetes is also needed as the current review did not appraise that.
“Some specific limitations include the fact that most of the RCTs did not explicitly compare the replacement of sugar consumption with non-sugar sweeteners, so the conclusions about avoiding non-sugar sweeteners are based on indirect deduction. Moreover, a head-to-head comparison of non-sugar sweeteners versus water as replacement for sugar sweetened beverages was not conducted. Also, individual non-sugar sweeteners were not explicitly assessed and were likely to include those that have been available on the market for many years and newer sweeteners were less represented. So, for the guideline the non-sugar sweeteners have been considered as a class of compounds collectively without distinguishing between individual types of non-sugar sweeteners.
“It is important to note that the WHO have stated clearly that the target audience for this guideline includes policy makers, non-governmental and other organisations, health professionals, researchers, educators and representatives of the food industry. By deduction, it is not intended for direct dissemination to individual members of the public in its current form and it would be better for information to be formulated appropriately by national and local agencies to be made context specific in a global context.
“The most critical issue is the “how” factor. Translating the guideline into action will require concerted action from many players including policy makers, public health agencies, food manufacturers and ultimately also require a degree of behaviour change by individuals. The goal is to reduce free sugars in the diet by replacing them with healthier, naturally occurring sweeteners such as from fruits and through unprocessed or minimally processed foods and drinks that improve overall diet quality.”
This extensive review by the WHO adds meaningfully to the scientific understanding on the relationship between NSS consumption and multiple indicators of human health. The key take-away is that for longer term weight management and for chronic health conditions such as the development of future type 2 diabetes and cardiovascular disease, the use of NSS is not advisable.
For the observational studies, the scientific review was explicit in describing the potential confounders that each study took account of, and mostly this was done fairly comprehensively such as by including factors like age, sex, body mass index and others. Still, acknowledging limitations, the guideline recommendation is stated as conditional.
It is really important to be clear that the guideline is not suggesting banning the use of NSS as the scientific review the WHO undertook was not about the chemical or safety issues, which is assessed separately in toxicological assessments that pronounce on safe limits of intake.
This review excluded research on polyols (sugar alcohols) because these are not non-nutritive as they contain carbohydrate, though they have lower calorie content than table sugar. Polyols such as sorbitol, xylitol, erythritol and others are extensively used in sugar-free foods and beverages. There is emerging evidence for potential adverse associations with chronic disease endpoints but this has not been systematically studied and should be further researched going forward.
Prof Tom Sanders, Professor emeritus of Nutrition and Dietetics, King’s College London, said:
“This guidance by WHO is based on a systematic review of trials/prospective cohort studies which show that artificial sweeteners per se neither result in weight loss nor weight gain. It is to be noted that quality of evidence was rated as low for any disease relationships.
“What the review does not consider is the impact of replacing sugar sweetened drinks with artificially sweetened drinks. There are high quality randomized controlled trials that show that when artificially sweetened drinks covertly replace sugar sweetened drinks in children they help prevent unhealthy weight gain.
“In my opinion this advice, which is based mainly on a null effect of artificial sweeteners on weight gain, is likely 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.”
Dr Ian Johnson, Nutrition researcher and Emeritus Fellow, Quadram Institute, said:
“This new guideline is based on a thorough assessment of the latest scientific literature, and it emphasises that the use of artificial sweeteners is not a good strategy for achieving weight loss by reducing dietary energy intake. However, this should not be interpreted as an indication that sugar intake has no relevance to weight-control. A better alternative to the use of artificial sweeteners is to reduce consumption of manufactured products containing free sugars, such as sugar-sweetened beverages, to use raw or lightly processed fruit as a source of sweetness, and perhaps, in the longer term, to try to reduce one’s overall taste for sweetness.”
Dr Duane Mellor, Registered Dietitian and Senior Lecturer, Aston Medical School, Aston University, said:
“This is an interesting report which highlights that non-sugar sweeteners are not inert metabolically, they have some effects so do not always provide the energy deficit that might be expected to help weight control. This could explain why although safe to use they are not recommended as a simple swap for sugars in a number of dietary guidelines, such as the British Dietetic Association (BDA).
“The report could be criticised as it 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. In the case of sweeteners, a number of trials have showed that they can help with weight control, whereas observational studies may not show an association between sweeteners and weight control. The reason observational studies do not suggest a benefit from switching to sweeteners could be that people who are trying to lose weight may choose sweeteners so from only observing it might look like those who use sweeteners tend to be overweight – something called reverse causality.
“However, overall this report highlights that universal replacement of sugar with sweeteners is not necessarily ideal, as this alone is unlikely to improve diet quality and produce the necessary changes to control weight long term. It is probably best not to stick with sugars to avoid sweeteners though – the answer is to try and reduce sugar intake. For some that might include using small amounts of sweeteners in foods and drinks as a way to reduce overall sugar intake.
“Sweeteners may still have a place as a transitional or stepping stone to help people reduce their sugar intake.”
WHO guideline: https://www.who.int/publications/i/item/9789240073616
WHO press release: https://www.who.int/news/item/15-05-2023-who-advises-not-to-use-non-sugar-sweeteners-for-weight-control-in-newly-released-guideline
Prof Nita Forouhi: “None.”
Prof Tom Sanders: “No conflicts of interest in the last 8 years that are relevant but I used to be a consultant to Nutrasweet about 15 years ago.”
Dr Ian Johnson: “No conflicts of interest.”
Dr Duane Mellor: “I have previously worked with the International Sweetener Association.”