There is no compelling evidence to indicate important health benefits – weight, glycaemic control, oral health, cancer, cardiovascular disease, kidney disease – of non-sugar sweeteners, a European evidence review found. Potential harms cannot be ruled out, found the study, which will inform a World Health Organisation guideline.
The review, led by Joerg J Meerpohl at the Institute for Evidence in Medicine (for Cochrane Germany Foundation), Medical Centre of the University of Freiburg and the Centre of Epidemiological and Statistical Research, Sorbonne Paris Cité, Inserm/Université Paris Descartes, Cochrane France.
Growing concerns about health and quality of life have encouraged many people to adopt healthier lifestyles and avoid foods rich in sugars, salt, or fat. Foods and drinks containing non-sugar sweeteners rather than regular ("free") sugars have therefore become increasingly popular.
Although several non-sugar sweeteners are approved for use, less is known about their potential benefits and harms within acceptable daily intakes because the evidence is often limited and conflicting.
To better understand these potential benefits and harms, the team of European researchers analysed 56 studies comparing no intake or lower intake of non-sugar sweeteners with higher intake in healthy adults and children.
Measures included weight, blood sugar (glycaemic) control, oral health, cancer, cardiovascular disease, kidney disease, mood and behaviour. Studies were assessed for bias and certainty of evidence.
Overall, the results show that, for most outcomes, there seemed to be no statistically or clinically relevant differences between those exposed to non-sugar sweeteners and those not exposed, or between different doses of non-sugar sweeteners.
For example, in adults, findings from a few small studies suggested small improvements in body mass index and fasting blood glucose levels with non-sugar sweeteners, but the certainty of this evidence was low.
Lower intakes of non-sugar sweeteners were associated with slightly less weight gain (-0.09 kg) than higher intakes, but again the certainty of this evidence was low.
In children, a smaller increase in body mass index score was seen with non-sugar sweeteners compared with sugar, but intake of non-sugar sweeteners made no differences to body weight.
And no good evidence of any effect of non-sugar sweeteners was found for overweight or obese adults or children actively trying to lose weight.
The researchers point out that this is the most comprehensive review on this topic to date, and will inform a World Health Organisation guideline for health experts and policy makers.
However, they stress that the quality of evidence in many of the studies was low, so confidence in the results is limited. And they say longer term studies are needed to clarify whether non-sugar sweeteners are a safe and effective alternative to sugar.
In a linked editorial, Vasanti Malik at Harvard TH Chan School of Public Health agrees that more studies are needed to understand the potential health effects of non-sugar sweeteners and to guide policy development.
Based on existing evidence, she says use of non-sugar sweeteners as a replacement for free sugars, particularly in sugar sweetened drinks, "could be a helpful strategy to reduce cardiometabolic risk (chances of having diabetes, heart disease or stroke) among heavy consumers, with the ultimate goal of switching to water or other healthy drinks."
"Policies and recommendations will need updating regularly, as more evidence emerges to ensure that the best available data is used to inform the important public health debate on sugar and its alternatives," she concludes.
Objective: To assess the association between intake of non-sugar sweeteners (NSS) and important health outcomes in generally healthy or overweight/obese adults and children.
Design: Systematic review following standard Cochrane review methodology.
Data sources: Medline (Ovid), Embase, Cochrane CENTRAL, WHO International Clinical Trials Registry Platform, Clinicaltrials.gov, and reference lists of relevant publications.
Eligibility criteria for selecting studies: Studies including generally healthy adults or children with or without overweight or obesity were eligible. Included study designs allowed for a direct comparison of no intake or lower intake of NSS with higher NSS intake. NSSs had to be clearly named, the dose had to be within the acceptable daily intake, and the intervention duration had to be at least seven days.
Main outcome measures: Body weight or body mass index, glycaemic control, oral health, eating behaviour, preference for sweet taste, cancer, cardiovascular disease, kidney disease, mood, behaviour, neurocognition, and adverse effects.
Results: The search resulted in 13 941 unique records. Of 56 individual studies that provided data for this review, 35 were observational studies. In adults, evidence of very low and low certainty from a limited number of small studies indicated a small beneficial effect of NSSs on body mass index (mean difference −0.6, 95% confidence interval −1.19 to −0.01; two studies, n=174) and fasting blood glucose (−0.16 mmol/L, −0.26 to −0.06; two, n=52). Lower doses of NSSs were associated with lower weight gain (−0.09 kg, −0.13 to −0.05; one, n=17 934) compared with higher doses of NSSs (very low certainty of evidence). For all other outcomes, no differences were detected between the use and non-use of NSSs, or between different doses of NSSs. No evidence of any effect of NSSs was seen on overweight or obese adults or children actively trying to lose weight (very low to moderate certainty). In children, a smaller increase in body mass index z score was observed with NSS intake compared with sugar intake (−0.15, −0.17 to −0.12; two, n=528, moderate certainty of evidence), but no significant differences were observed in body weight (−0.60 kg, −1.33 to 0.14; two, n=467, low certainty of evidence), or between different doses of NSSs (very low to moderate certainty).
Conclusions: Most health outcomes did not seem to have differences between the NSS exposed and unexposed groups. Of the few studies identified for each outcome, most had few participants, were of short duration, and their methodological and reporting quality was limited; therefore, confidence in the reported results is limited. Future studies should assess the effects of NSSs with an appropriate intervention duration. Detailed descriptions of interventions, comparators, and outcomes should be included in all reports.
Ingrid Toews, Szimonetta Lohner, Daniela Küllenberg de Gaudry, Harriet Sommer, Joerg J Meerpohl
[link url="https://www.sciencedaily.com/releases/2019/01/190102193733.htm"]BMJ material[/link]
[link url="https://www.bmj.com/content/364/bmj.k4718"]BMJ abstract[/link]