Paper
D.E. Cummings, D.S. Weigle, R. S. Frayor, P. A. Breen, M.K. E. P. Dellinger, J. Q. Purnell.
Plasma Ghrelin levels after diet-induced weight loss or gastric bypass.
Ghrelin and Regulation of Body Weight. N Engl J Med, Vol. 346, No. 21. May 23, 2002.
Review
Background
Weight unbalances entail disturbances in appetite and energy expenditure that endorse weight regain (lost). Ghrelin is a neuroendocrine hormone that enhances food consumption in rodents and humans.
If circulating ghrelin participates in the adaptive response to weight loss, its levels should rise with dieting.
Because ghrelin is produced primarily by the stomach, weight loss after gastric bypass surgery may be accompanied by impaired ghrelin secretion.
Methods
It was determined the 24-hour plasma ghrelin profiles, body composition, insulin levels, leptin levels, and insulin sensitivity in 13 obese subjects before and after a six-month dietary program for weight loss.
The 24-hour ghrelin profiles were also determined in 5 subjects who had lost weight after gastric bypass and 10 normal-weight controls; 5 of the 13 obese subjects who enrolled in the dietary program were matched to the subjects in the gastric bypass group and served as obese controls.
Results
Plasma ghrelin levels went up sharply shortly before and fell shortly after every meal (I have named that the zeroth law). A diet-induced weight loss of 17 percent of initial body weight was associated with a 24 percent increase in the area under the curve for the 24-hour ghrelin profile (P=0.006).
In contrast, despite a 36 percent weight loss after gastric bypass, the area under the curve for the ghrelin profile in the gastric-bypass group was 77 percent lower than in normal-weight controls (P<0.001) and 72 percent lower than in matched obese controls (P=0.01). The normal, meal-related fluctuations and diurnal rhythm of the ghrelin level were absent after
gastric bypass.
Conclusions
The increase in the plasma ghrelin level with diet-induced weight loss is consistent with the hypothesis that ghrelin has a role in the long term regulation of body weight.
Gastric bypass is associated with markedly suppressed ghrelin levels, possibly contributing to the weight-reducing effect
of the procedure.
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