ISA response to the study by Wang et al. entitled “Sucralose promotes food intake through NPY and a neuronal fasting response”.
Contrary to claims by Wang et al., made in relationship to a new study which focuses on investigations in fruit flies, there is a broad body of scientific evidence which clearly demonstrates that low calorie sweeteners do not increase appetite or have any negative impact on energy or food intake in humans.
The study by Wang et al., published in Cell Metabolism, found that fruit flies fed diet (sucrose and yeast) with a high concentration (2.5%) of sucralose for a period of 5-6 days increased their intake of calories in the next 3-4 days. They further found this “appetite-stimulating effect was reversible, and food intake returned to control levels within 3 days.” Other changes were reported that appear consistent with changes caused by insufficient energy. The authors remark that the changes in food intake were not due to an effect on gut microflora, as the same kind of effect was observed when the investigations were done in germ-free fruit flies or fruit flies treated with tetracycline (an antibiotic). Wang et al. conducted other investigations that indicate that the effect of such prolonged administration of a diet with a very high sucralose concentration is mediated, instead, by changes in “a neuronal starvation pathway”, which in turn regulates signalling related to food intake. In general, their tests found that fruit flies were detecting “a discrepancy between dietary sweetness and energy”. From this study, the authors conclude that their “results show that prolonged consumption of a sucralose-sweetened diet promotes hunger and how animals perceive nutritive sugar.”
The University of Sydney issued a press release on it, which, not surprisingly, was picked up by numerous media outlets, given the Wang et al. conclusions.
A critical analysis of this report by Wang et al., however, leaves much to be desired with regard to the authors’ interpretation of their study results.
The authors neglect to point out that people will never be consuming sucralose in a way that mimics what was given to the fruit flies in their investigations. If a person were to consume a diet with 2.5% sucralose in it, it would be like consuming more than 3 pounds of sugar a day. Moreover, Wang et al. gave this diet to the fruit flies for 5-6 days in order to produce an effect. In the life of a fruit fly, this is about 1/10 of its entire lifespan. An overall caloric deficit resulting from such a treatment could easily be expected, and easily expected to result in a subsequent “over-eating” for a period of time. This is exactly what was seen, and the effect was transient. Caloric intake returned to normal when the flies were removed from the sucralose diet that had less caloric value.
Clearly, the results of this isolated study should not be considered evidence that use of low calorie sweeteners by people will lead to overeating.
Additionally, while the authors remark that their results are supported by a short-term (7-day) investigation also performed in only a small number of mice, much longer-term (e.g., 6-month) and much larger studies in rodents show that sucralose, even at doses similar to those used in the fruit fly investigations, do not cause increase in body weight, nor promote excessive food intake.
In their discussion of their fruit fly investigations, Wang et al. also ignore reporting a wealth of studies from the scientific literature that show that sucralose and other low calorie sweeteners are without adverse effect on either appetite or body weight. For example, while the authors speculate that their results could be related to insulin control and response, clinical studies show that sucralose does not affect either insulin secretion or blood glucose control;2-9 and generally support no effect of sucralose on secretion of incretins with an involvement in gastrointestinal regulation of appetite.7,10-11
Similarly, the authors’ conclusions that human consumption of low calorie sweeteners could result in increases in caloric consumption is simply not supported by clinical trials.12-16 Studies in people, using widely differing methodologies in different human groups (men, women, lean, obese, never obese, formerly obese), reach largely consistent conclusions: low calorie sweeteners can be effective tools in helping to lower body weight by replacing sugar, and they do not result in overeating. In fact, in many clinical studies, the use of low calorie sweeteners is associated with a decreased energy intake and a lower consumption of sweet tasting products.17 Moreover, research indicates that people who use low calorie sweeteners may have overall better diet quality.18-20
In general, the relevance of studies on appetite in fruit flies to the appetite of humans is questionable. Moreover, results of studies in animal (or insect) models are not always reflective of the human response, particularly when the study protocol may make data extrapolation to humans suspect, as is the case with the study by Wang et al.
Isolated studies, such as this study by Wang et al., are superseded by the collective evidence in humans affirming that the consumption of low calorie sweeteners including sucralose do not trigger increased food intake.21 The sum of peer-reviewed randomised controlled trials (RCTs), the gold standard in human nutrition research, show that low calorie sweeteners can be an effective tool in weight management, as they help people manage overall calorie intake.22 Furthermore, recently published systematic reviews and meta-analyses have concluded that the balance of evidence shows that actually the use of low calorie sweeteners in foods and drinks leads to reduced energy intake and body weight.23,24
In short, the study by Wang et al. is not supported by a wealth of scientific research, which shows that low calorie sweeteners, including sucralose, are safe and a helpful tool for nutritional management of body weight.
To read ISA statement on this study by Wang et al., please click here.