Functional magnetic resonance imaging of human hypothalamic responses to sweet taste and calories.
BACKGROUND
Evidence exists that beverages do not trigger appropriate anticipatory physiologic responses, such as cephalic phase insulin release. Therefore, it is of interest to elucidate the food properties necessary for triggering adaptive responses. Previously, we found a prolonged dose-dependent decrease in the hypothalamic functional magnetic resonance imaging signal after ingestion of a glucose solution.


OBJECTIVE
The aims of the present study were to measure the effects of sweet taste and energy content on the hypothalamic response to glucose ingestion and to measure the concomitant changes in blood glucose and insulin concentrations.


METHODS
Five healthy, normal-weight men participated in a randomized crossover design trial. The subjects were scanned 4 times for 37 min on separate days with functional magnetic resonance imaging. After 7 min, they ingested 1 of the following 4 stimuli (300 mL of each): water (control), a glucose solution, an aspartame (sweet taste) solution, or a maltodextrin (nonsweet carbohydrate) solution.


RESULTS
Glucose ingestion resulted in a prolonged and significant signal decrease in the upper hypothalamus (P < 0.05). Water, aspartame, and maltodextrin had no such effect. Glucose and maltodextrin ingestions resulted in similar increases in blood glucose and insulin concentrations. However, only glucose triggered an early rise in insulin concentrations. Aspartame did not trigger any insulin response.


CONCLUSIONS
Our findings suggest that both sweet taste and energy content are required for a hypothalamic response. The combination of sweet taste and energy content could be crucial in triggering adaptive responses to sweetened beverages.
Smeets
Paul A M
PA
Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands. paul@isi.uu.nl
de Graaf
Cees
C
Stafleu
Annette
A
van Osch
Matthias J P
MJ
van der Grond
Jeroen
J
D000328:Adult; D001218:Aspartame / Q000008:administration & dosage / Q000494:pharmacology; D001628:Beverages; D001786:Blood Glucose / Q000378:metabolism*; D018592:Cross-Over Studies; D004063:Digestion; D002149:Energy Intake / Q000502:physiology*; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D007031:Hypothalamus / Q000033:anatomy & histology / Q000502:physiology*; D007328:Insulin / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D008297:Male; D011134:Polysaccharides / Q000008:administration & dosage / Q000494:pharmacology; D013549:Sweetening Agents / Q000008:administration & dosage / Q000494:pharmacology; D013649:Taste / Q000187:drug effects / Q000502:physiology*
D001786:Blood Glucose; D007328:Insulin; D011134:Polysaccharides; D013549:Sweetening Agents; C008315:maltodextrin; D005947:Glucose; D001218:Aspartame