No compelling evidence that non-sugar sweeteners aid weight loss efforts, notes major review

04 Jan 2019 --- There is no compelling evidence that non-sugar sweeteners (NSSs) improve health or help people to lose weight, a major review published in the British Medical Journal (BMJ) has found. As Public Health England (PHE) continues to pressure the food industry into slashing the sugar content in many products by 20 percent by 2020, compared to 2017 rates, companies are increasingly opting to use artificial sweeteners instead of sugar. Coupled with rising consumer concerns around obesity and diabetes, sugar consumption, reduction and alternatives have been thrown under the spotlight.

Alongside government pressure, increased consumer interest in reducing energy intake has led to a rise in popularity for food products containing non-sugar sweeteners, such as aspartame and steviol glycosides, rather than simple sugars. Findings, such as those from PHE, that by the age of ten, children have already exceeded the maximum recommended sugar intake for an 18-year-old, may spur consumer concern. As cited in the study, “replacement of sugars with NSSs bears the promise of health benefits, primarily by reducing the contribution of sugars to daily calorie intake and thus reducing the risk of unhealthy weight gain.”

However, the evidence on the potential benefits and harms of NSSs is often limited and conflicting, according to the European researchers.

The review, which was prepared to inform the upcoming World Health Organization (WHO) guideline on NSSs usage, analyzed 56 studies comparing no intake or lower intake of NSSs with higher intake in healthy adults and children. 

Most health outcomes did not display differences between the NSS exposed and unexposed groups in adults or children. This was true for body weight, diabetes or glycemic control, appetite, blood pressure and bladder or lower urinary tract cancer risk, according to the review.

Lack of supporting data
The research also highlights the lack of quality research in this arena. The researchers noted that their confidence in the 372 studies considered for the review that investigated the effects of NSS intake on different health outcomes was “low to moderate.” Problems lay in the fact that most studies had small sample sizes and durations too short to infer any meaningful results in the longer term, for example.

The researchers also identified that most of the studies considered in their review are limited in that they used single sweeteners. Such use differs from that in real life practice. 

For example, NSSs can be consumed in different ways, including as a tabletop sweetener, whereby the dose is freely determined by users themselves and might be higher than in that recorded the studies. Moreover, by contrast to many of the included studies that used a single NSS only, many food items have different types of NSSs that are combined to cover different bitter or metallic aftertastes of individual sweeteners and provide an adequate sweetness.

Future research might consider exploring the effects of different combinations of sweete Increased consumer interest in reducing energy intake has led to a rise in popularity for food products containing non-sugar sweeteners. ners in doses similar to real life use patterns and compare the effects of higher versus lower NSS doses.

What has the response been?
Speaking to NutritionInsight, Dr. Fred Brouns of Maastricht University’s Faculty of Health, Medicine and Life Sciences, notes that non-caloric sweeteners are often positioned as healthy alternatives to sugar based on a number of direct comparative studies.

According to Brouns, when compared to sucrose, these sweeteners do not have a detrimental effect on dental health, are favorable in terms of less desirable metabolic effects such as inhibition of lipid oxidation and they do not deliver calories and, therefore, should reduce weight gain risks.

Critically, however, Brouns states that the long-term effects of health indices, such as body weight, diabetes and cardiovascular disease, are all interrelated and are dependent on lifestyle. 

“Thus, although NSSs may support to reduce the risks, the final risks will depend on many other factors,” he adds. 

“The current review in BMJ does not show that NSSs have unfavorable effects, but instead shows that there is a lack of long-term controlled studies. The latter should be addressed in future.”

In response to the review, the trade group International Sweeteners Association (ISA) pointed out an accompanying editorial by Vasanti Malik in the BMJ. The editorial said that among adults, findings from the randomized controlled trials comparing low-calorie sweeteners’ intake with sugar intake suggested small improvements in body mass index and fasting concentrations of blood glucose favoring low-calorie sweeteners. Among children, low-calorie sweeteners intake led to a more modest increase in body mass index score than sugar intake.

Finally, serious limitations plague the review, the ISA claims, which are also discussed in the BMJ editorial by Vasanti Malik. 

The review has excluded important and well-designed trials, that have examined the longer-term effects of low calorie sweetened products on weight management. 

“For example, the year-long randomized clinical trial by Peters et al. clearly showed a beneficial effect of low calorie sweetened drink intake on both weight loss and weight loss maintenance (Peters et al., 2014; 2016). By excluding such studies, the outcomes of the review and meta-analysis might well have been affected,” the ISA state.

Overall, the wealth of scientific evidence to date demonstrates that low-calorie sweeteners can be helpful tools not only in weight management, when used to replace sugar and as part of a calorie-controlled diet and a healthy lifestyle, but also as a significant aid to people with diabetes, as they do not affect blood glucose control, the ISA concludes in its statement.

NutritionInsight reached out to several non-sugar sweeteners suppliers, with Tate & Lyle, for example, reiterating the ISA statement.

Further commenting on the study, “the BMJ paper calls for longer and more detailed studies, and these are always desirable, but difficult and costly to carry out. I suspect one of the issues with the BMJ review is the inclusion of some rather poorly-designed studies, the inconclusive results of which are obscuring the true benefits of low-energy sweeteners,” says John Fry, Director at Connect Consulting and expert on low-calorie sweeteners.

Fry also shares his “disapointment” in the findings, noting that “it is barely two months since the ISA's London conference of international experts laid out in detail the science behind the effective use of non-sugar sweeteners to improve health, yet the BMJ publication appears to deny their value.”

In response to the study, Gavin Partington, Director General at British Soft Drinks Association (BSDA), stressed that the review did not find solid evidence of any major safety issues. “Low- and no-calorie sweeteners allow consumers to enjoy sweetness while managing sugars and calories in their everyday lives. Because they taste good and are low- or calorie-free, people are more likely to combine them with a balanced diet and healthy lifestyle and stick to their dietary goals for weight management," Partington notes. “In March 2017, the UK Government and Public Health England publicly endorsed the use of low-calorie sweeteners as a safe alternative to reduce sugar in food and drink and help people manage their weight. The increased use of low-calorie sweeteners in soft drinks has led to a significant reduction in sugar and calorie intake (from soft drinks). Kantar Worldpanel data shows overall sugar intake from soft drinks is down by 22.9% since 2014," he concludes.

By Laxmi Haigh