Glucose-loaded dopamine transporter is associated with mood altering effect of sweet foods and control over eating sweets

Dopamine transporter (DAT) mediates reuptake of extracellular dopamine into presynaptic neurons. We investigated the effects of glucose loading on striatal DAT in healthy young adults who underwent 18F-FP-CIT positron emission tomography (PET) scans, and sweet taste questionnaire (STQ). Thirty-five healthy subjects were enrolled in this study. Each subject visited the institution three times, for three brain PET scans (two 18F-FP-CIT PET scans after the infusion of glucose or placebo and one 18F-Fluorodeoxyglucose PET scan). All subjects underwent STQ, 12-item self-reporting to evaluate subjects’ reactions to eating sweets, craving for sweets and degree of control over eating sweet foods (STQ 1: sensitivity to mood altering effect of sweets, and STQ 2: impaired control over eating sweet foods). We created Bayesian models separately with STQ 1, and STQ 2 as predictors, with DAT availability and brain glucose uptake as a dependent variable. From caudate, glucose-loaded DAT availability was significantly higher than placebo-loaded DAT availability, and from putamen, glucose-loaded DAT availability showed the higher trend than placebo-loaded DAT availability. STQ was positively associated with glucose-loaded DAT availability. The effect of STQ markedly overlapped with zero on placebo-loaded DAT availability, and brain glucose uptake. In conclusion, the change of striatal DAT availability after glucose loading is associated with the vulnerability to sweet foods. This may indicate that individuals with higher DAT availability after glucose loading experience a rapid clearance of synaptic dopamine after consuming sweet foods, potentially leading to a desire for additional sweet foods. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement No funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by the institutional review board of Pusan National University Hospital (PNUH-1707-019-057) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors