What is Ghrelin, and how does it affect me?
Ghrelin is a hormone that circulates throughout our body, but is mostly produced by certain cells (with ‘oxyntic’ glands) in our stomach. We have found that ghrelin has many roles; it causes a mild inflammatory response and dilates our blood vessels, it affects our regulation of insulin and glucose, but ghrelin is mostly known as the “hunger hormone.”
Ghrelin is unique because it is the only hormone proven to be a potent appetite stimulant (infusions have even been used to help treat cancer-induced weight loss). We have demonstrated ghrelin is increased in our circulation just prior to a meal; and in lean subjects, ghrelin levels fall immediately following food ingestion. In obese subjects, ghrelin levels did not fall in similar fashion following food ingestion (and many presume that this explains the pathogenesis of obesity).
Interestingly, diet-induced weight loss is associated with an increase in ghrelin levels. Weight loss following operations that remove the major source for ghrelin (Sleeve Gastrectomy) or diverge the stream of food from all but a small pouch of stomach (Gastric Bypass) cause a dramatic reduction in ghrelin levels. This helps to increase satiation between meals, and lessen grazing!