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Scientists comment on a SACN statement on the WHO’s guideline on non-sugar sweeteners (NSS).
Prof Oliver Jones, Professor of Chemistry, RMIT University, said:
“Although the language used is quite technical in places, I think the report from the findings of the Scientific Advisory Committee on Nutrition is a good summary of some very complex data. They basically say that the best evidence we have shows that foods sweetened with non-sugar sweeteners (such as aspartame and stevia) can help people lose a small amount of weight compared to eating and drinking the same products sweetened with sugar. They also note that there is no strong evidence of harm from non-sugar sweeteners.
“What this means for the public is not very different from previous advice. The advice from nutrition bodies is to have a balanced diet and avoid taking in too much sugar – for example, fruit drinks such as orange juice often have the same level of acidity and sugar as soft drinks, so it is best not to drink too much of them. The committee does recommend not using too many non-sugar sweeteners because they can lead to confusion about calorie intake, and weight management is a multifaceted issue that needs to be looked at holistically.
“Overall, though, I think what is presented in the report is sensible advice.”
Prof Jules Griffin, Director of the Rowett Institute, University of Aberdeen, said:
“The response by SACN raises concerns with how the WHO has weighted the evidence they reviewed from two different study designs – randomised control trials (RCT) and prospective cohort studies (PCS). The issue is that PCS studies detect associations but do not prove causation. The response by SACN raises the concern that PCS studies might be confounded, for example by the fact that those people with high non-sugar sweetener (NSS) consumption might consume more of these drinks because they are overweight or living with obesity and so the NSS drinking is a consequence of weight gain and not a cause. SACN favours the RCT design because they can test causation if properly conducted – but they are more expensive to perform so tend to be shorter in duration.
“What is notable about the WHO report and the SACN response is actually the paucity of evidence to base recommendations on. Despite the large consumption of NSS drinks by parts of the population, we don’t have conclusive evidence of benefits or drawbacks on some pretty fundamental outcomes including tooth decay, weight gain and type 2 diabetes, with studies showing opposite outcomes. This is surprising as it is relatively easy to track the metabolism of these NSS in the blood and urine and this does seem like a major knowledge gap given consumption rates of these types of drinks. The SACN response also raises concerns around recommendations being made on a lack of evidence or conflicting evidence, which is essentially what WHO did, leaving both the food and drink industry and people struggling with weight management with very few options.”
Dr Hilda Mulrooney, Reader in Nutrition & Health, London Metropolitan University, said:
Non-sugar sweeteners (NSS):
“SACN has carried out a rapid review of NSS and made precautionary recommendations, since the evidence is inconsistent in relation to health outcomes and NSS intakes. The SACN review says that younger children should not be given foods or drinks sweetened either with sugar or non-sugar sweeteners. Older children and adults may benefit from non-sugar sweeteners as an alternative to sugar in foods and drinks even temporarily in order to achieve a reduction in their sugar and calorie intakes. In the longer term, it is recommended that intakes of both should be reduced.
“SACN shares the concerns expressed by WHO that NSS are associated with adverse health outcomes. However, they noted that the data are largely observational with some potential for confounding and for reverse causality (e.g. people already living with excess weight may use NSS-sweetened products as part of weight control measures). Unlike WHO, SACN placed greater weight on findings from randomised control trials (higher quality evidence) albeit little of this higher quality data was available. SACN also identified small weight losses in those consuming non-sugar sweeteners as potentially beneficial even if subsequent weight regain occurred, so they identified potential for non-sugar sweeteners as part of weight management strategies in the short term. Similarly in relation to dental health the potential for NSS to enable lower sugar consumption was identified, but NSS consumption was not considered essential to achieve either lower sugar intakes or weight control.
Processed foods:
“SACN has also updated1 their previous rapid review (2023) including additional studies using NOVA and considered to be of higher quality. They have concluded that observations of links between UPF consumption and worse health outcomes are of concern. However, much of the research is observational, and there are inconsistencies in accounting for possible confounders such as socioeconomic status, energy and nutrient intakes and body mass intake. They previously found that the UK National Diet and Nutrition Survey (NDNS) does not map exactly against the NOVA categories. In this update one study which did apply NOVA to NDNS categories found partial overlap between UPF classification and products high in saturated fat, salt and sugar. UPF products tended to have less healthy nutrient profiles than minimally processed foods. Not all UPF categories were associated with adverse health impacts; categories that were included sweetened drinks, meat and animal products. Mixed results were found for several categories including bread and cereals, savoury snacks and dairy products – the reasons for this are unclear.
“UPFs may be markers of less healthy diets and lifestyles; the NOVA classification is based only on the degree of processing and not the nutritional composition of the foods.
“SACN advice remains consistent; to meet healthy eating recommendations for nutrients such as fibre, the diet should contain more wholegrains, fruit and vegetables. In relation to the UPF categories associated with adverse health outcomes (namely sweetened drinks, meat and animal products), SACN has previously recommended reducing intakes of these foods in line with healthy eating guidance and known links between (for example) high red and processed meat intakes and cancer risk. An estimated 51-68% energy intake in the UK diet derives from UPF and given that many of these are also high in fat, salt and sugar, the advice remains that intakes of these foods should be reduced – this recommendation has been and remains based on their nutrient compositions.
“Both reviews are consistent with previous recommendations, build upon previous work and take into account other recommendations (e.g. Government Office for Science recommendations that only higher quality evidence in relation to UPF and health outcomes be used).”
Prof Graham Finlayson, Chair in Psychobiology and Dr Catherine Gibbons, Associate Professor, both from the School of Psychology, University of Leeds, said:
“The SACN report provides a well-balanced and evidence-based evaluation of non-sugar sweeteners (NSS) in the UK diet. By prioritizing high-quality randomized controlled trials over observational studies, SACN offers a nuanced perspective on the potential benefits and limitations of NSS for weight management and overall health.
“The WHO’s recommendations against NSS seem to be based on a lack of long-term trial data, rather than clear evidence of harm. Much of the existing research on NSS in solid foods—where they make up most of our dietary intake—is missing.
“Our recent €9M EU-funded SWEET project1 put this to the test, examining artificial (Neotame) and plant-based (Stevia Reb M) sweeteners in biscuits compared to added sugar. The results showed no negative NSS effects on appetite, no disruption to endocrine responses, and potential benefits for blood sugar control—findings that directly challenge fears around NSS in food.
“Taking precaution with NSS consumption, especially in children, is reasonable but the evidence isn’t strong enough to dismiss NSS as a tool for reducing sugar intake. With obesity and diabetes rates rising, knee-jerk policy changes could do more harm than good.”
1 https://pubmed.ncbi.nlm.nih.gov/36564114/
Prof Robin May, Chief Scientific Adviser, FSA (Food Standards Agency), said:
“We welcome SACN’s advice on the consumption of non-sugar sweeteners and their call for further research.
“All sweeteners approved for use in foods in GB have been subject to a rigorous risk assessment before being authorised and the FSA maintains strict oversight of these products. We strongly support SACN’s call for industry to make data on the quantity of these sweeteners in their ingredients publicly available to provide better information on how much people are consuming and to help inform our assessments of these ingredients.”
Dr Havovi Chichger, Senior Lecturer in Biomedical Science, Anglia Ruskin University, said:
“The SACN recommendations published in their position statement this morning are highly appropriate given the WHO report and research findings in the field. The committee recommends that children not be given drinks containing non-nutritive sweeteners and that adults work towards a sweetener-free diet. Although the use of non-nutritive sweeteners is an important tool to reduce sugar overconsumption, and the related negative health effects, we now understand that these sweet additives can pose various health risks on the public. It might seem contradictory, but studies have shown that all commercially-available sweeteners are associated with the development of obesity and diabetes, potentially through a metabolic disruption pathway (Bonnet 2018; McLay-Cooke 2016; Stamataki 2020). The SACN position statement also recommends that the government monitor the amount of non-nutritive sweeteners in the UK diet and encourage the food and drink industry to clearly communicate the amount of sweeteners within labelling. These recommendations are based on an in-depth review of studies in the field however these studies do not always specify which sweeteners were consumed. There are also confounding factors to be considered, for example, the studies show a link between sweetener consumption and negative health outcomes which could be due to underlying and undetected health conditions rather than the sweetener itself. As such, there is a real need for large-scale studies in the field to understand the direct causative effect of non-nutritive sweeteners on human health.”
Prof Naveed Sattar, Professor of Cardiometabolic Medicine/Honorary Consultant, University of Glasgow, said:
“I think this is a very balanced statement. SACN have accepted that the best quality evidence available (i.e. randomised trials) show that non-sugar sweeteners (NSS) lower weight albeit modestly as compared to taking sugar rich drinks and that other types of evidence which suggest some harm from NSS are unreliable. I fully agree and would rather people take low calorie drinks with artificial sweeteners every time than sugar rich drinks both for weight and dental benefits and potentially other gains. However, SACN also correctly points out that until we have more evidence in the future on benefits and safety of NSS, it would be best to limit the intake of all such sweetened (including NSS) drinks in early childhood so that children become accustomed to drinking unsweetened drinks, preferably water. A sensible and mature summary of a complex set of data.”
Declared interests
Prof Oliver Jones: “I don’t have any conflicts of interest to declare except that many years ago I worked on a project funded by the Food Standards Agency. I am also quite fond of Pepsi Max (in moderation).”
Prof Jules Griffin: “My conflict of interest is that I have served on a SACN expert panel to assess the UK recommendations for saturated fat intake in the UK and its role in health and non-communicable disease.”
Dr Hilda Mulrooney: “I am a committee member of the British Dietetic Association Obesity Group; a committee member of the European Specialist Dietitians Network (Obesity) and a member of the Obesity Management Collaborative. I am Council Member for Public Health of the Nutrition Society. All of these positions are voluntary and unpaid.”
Prof Graham Finlayson: “No conflicts of interest to declare, other than being involved in the SWEET EU-funded project which is included in the quote.”
Prof Robin May: “Robin’s academic’s post is at University of Birmingham, and he sits on Scientific Advisory Committee for Genetic Modification (which is an unpaid role). CSA at the food regulator; FSA SAC webpage: https://sac.food.gov.uk/.”
Dr Havovi Chichger: “Prof Chichger has no conflict of interest or other in this review.”
Prof Naveed Sattar: “Only that I often drink diluting juice with NSS.”