July 12, 2016

expert reaction to artificial sweeteners and appetite

In a new study published in the journal Cell Metabolism scientists have investigated how consumption of synthetic sweeteners affects food intake in fruit flies.

Dr Dominic Dwyer, Reader in Psychology, Cardiff University, said:

How robust is this paper?

“The basic effect of sucralose exposure enhancing subsequent energy intake is clearly robust as it is replicated several times within the separate experiments of the paper.  The different experiments that probe a number of genetic, metabolic, and neural mechanisms for this overall effect are not repeated in the same way, but there is no obvious problem that would question the robustness of this work.”

Does this provide good evidence that artificial sweeteners can increase our appetites?

“The fact that exposure to artificial sweeteners can increase food intake (especially intake of sweet calorie-containing foods) is already well established through epidemiological studies in people and behavioural work in rodents. The current study explores the neural mechanisms for this effect, including the role of the neurotransmitter NPY – Neuropeptide Y (in humans, the equivalent is NPF – neuropeptide F in fruit flies), which is already known to play a key role in the regulation of food intake.”

This work was done in fruit flies – how transferable is it to humans?

“The fruit fly is an exceptionally useful model system for exploring neural and genetic systems, many of which are conserved to humans (and other species). Of course, not all mechanisms are identical, and so further work would be needed to confirm the systems revealed in the current work are also at play in humans. That said, the current study also extends the NPY results to mice, suggesting at least some of the mechanisms identified here are seen in mammals and not just fruit flies, and it should be remembered that the overall effect where exposure to artificial sweeteners enhances food intake has already been seen in humans. That said, in rodents, the effects of exposure to artificial sweeteners persists for a long time, in the current work, it seems only to impact on the behaviour of the flies for about 3 days. So, there might be some differences in the way that sweetener exposure affects food consumption in flies and mammals.

General comment:

“The rodent research in this area suggests that exposure to artificial sweeteners breaks the usual relationship between sweet tastes and calories, so that sweet tastes are no longer a signal that calories are being ingested. The current work is consistent with that general idea, and illustrates the metabolic and neural signalling mechanisms which underpin this effect.”

‘Sucralose Promotes Food Intake through NPY and a Neuronal Fasting Response’ by Wang et al. published in Cell Metabolism on Tuesday 12^th July. 

Declared interests

Dr Dwyer: “No declarations of interest.”