The effect of intestinal glucose load on neural regulation of food craving

ABSTRACT

Objectives: Excess sugar consumption, particularly in the form of sweetened beverages, has been identified as a pivotal contributor to the epidemic of obesity and associated metabolic disorders. However, the impact of sugar-sweetened beverages on food craving is still inconclusive. Therefore, the present study aimed to specifically investigate the effects of an intestinal glucose load on neural processing of food cues.

Methods: Using a single-blind fMRI design, 26 normal-weight women were scanned on two occasions, after receiving either a glucose or water infusion directly into the stomach using a nasogastric tube, without being aware of the type of infusion. Participants had to either view neutral and food images, or were asked to distract themselves from these images by solving an arithmetic task.

Results: In response to viewing high-caloric food cues, we observed increased activation in reward-related brain areas. During food distraction, fronto-parietal brain regions were recruited, which are commonly related to attentional deployment and hedonic valuation. Furthermore, activity in the dorsolateral prefrontal cortex showed increased functional connectivity with the insula and was correlated with subjective craving levels to food cues. Despite an increase of blood glucose levels in response to the glucose compared to the water infusion, neither subjective food craving nor neural regulation of food craving showed significant differences.

Conclusions: These findings support a decreased satiation effect of sweet beverages, as intestinal glucose ingestion and signalling showed no significant effect on cortical brain circuits associated with food craving. This trial was registered at clinicaltrials.gov as NCT03075371.

KEYWORDS:

• FMRI
• glucose ingestion
• food distraction
• craving

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

M.A.S. is a PhD student at the Psychological Institute of Heidelberg University and research assistant at the Department of General Internal Medicine and Psychosomatics of the University Hospital Heidelberg. H.C.F. is the head of the Department of General Internal Medicine and Psychosomatics and S.P. is a tenured professor at the chair of Developmental and Biological Psychology of Heidelberg University. S.S. is a doctoral candidate at the Department of General Internal Medicine and Psychosomatics. M.B. is the head of the Department of Neuroradiology and W.H. is the former head of the Department of General Internal medicine and dean of the Medical Faculty of Heidelberg University. J.J.S. is senior researcher at the Department of General Internal Medicine and Psychosomatics. M.A.S. analysed data and wrote the manuscript; H.C.F. and J.J.S. designed and supervised the research; M.A.S. and S.S. conducted research; S.P., M.B. and W.H. advised on the data analyses and reviewed the manuscript.

Additional information

Funding

This study was supported by a DFG (Deutsche Forschungsgemeinschaft) [grant number SI 2087/2-1].