Morning ghrelin concentrations are not affected by short-term overfeeding and do not predict ad libitum food intake in humans.
BACKGROUND
Ghrelin has a short-term orexigenic effect but may also be a marker of food intake over time. We previously found an inverse association between ghrelin concentrations and food intake.


OBJECTIVE
The objectives were to determine whether the fasting plasma ghrelin concentration is related to food intake and whether the previous day's intake predicts the suppression of ghrelin.


METHODS
Sixty-nine nondiabetic adults (40 men) aged 33 +/- 9 y were studied as inpatients at a Clinical Research Center. After 6 d of consuming a maintenance diet, the subjects self-selected their food from our vending machine system for 3 d. Total plasma ghrelin concentrations were measured every morning during the vending machine period.


RESULTS
The fasting ghrelin concentration was negatively correlated with body mass index (r = -0.31, P = 0.016) and weight (r = -0.26, P = 0.044). Mean morning ghrelin concentrations remained constant (149 +/- 59, 152 +/- 60, 148 +/- 61, and 145 +/- 59 pg/mL on days 1, 2, 3, and 4, respectively) even though the subjects overate while using the vending machines (160 +/- 42% of weight-maintenance needs). No associations were found between daily ghrelin concentrations and subsequent food intake on any day (day 1: r = -0.04, P = 0.76; day 2: r = -0.01, P = 0.95; day 3: r = -0.11, P = 0.38). Suppression of total ghrelin concentrations was not associated with the previous day's intake or with subsequent food intake.


CONCLUSIONS
Morning plasma ghrelin concentrations do not affect acute increases in food intake. This trial was registered at clinicaltrials.gov as NCT00342732.
Votruba
Susanne B
SB
National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ 85016, USA. votrubas@mail.nih.gov
Kirchner
Henriette
H
Tschöp
Matthias
M
Salbe
Arline D
AD
Krakoff
Jonathan
J
D000328:Adult; D015992:Body Mass Index; D002940:Circadian Rhythm; D015331:Cohort Studies; D004435:Eating / Q000502:physiology*; D005215:Fasting / Q000097:blood; D005260:Female; D054439:Ghrelin / Q000097:blood*; D006801:Humans; D008297:Male; D018709:Statistics, Nonparametric
D054439:Ghrelin