What is ghrelin?

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Obligatory disclaimer: I am not a medical doctor, and the content of this website was created for informational purposes only. Such content is not intended as a substitute for medical advice, treatment or diagnosis.

Just like happened with our posts on starvation mode / starvation response, metabollic damage, and thermogenesis, chances are that you’ve heard about ghrelin. In this week’s post we’ll talk about ghrelin: what it is, and what it’s for.

What is ghrelin?

A quick Google search will tell you that ghrelin is the hunger hormone. Cool, so what does that mean? As we’ve covered before, hormones are substances that serve as chemical messengers. They are transported through the circulatory system to organs so that their phisiology and behavior can be regulated. In particular, ghrelin is a peptide secreted mainly by endochrine cells in the stomach and small intestine, and it stimulates food intake.

What is ghrelin for?

Once ghrelin is released by your stomach and small intestine, our feeling of hunger increases. In fact, ghrelin concentration in the blood rises when we fast (check this post for a definition on fasting), and it decreases right after eating, especially if we’ve ingested carbohydrates.

In addition to that, ghrelin also causes the release of Neuropeptide Y, which also stimulates hunger. Ghrelin, neuropeptide Y and leptin are hormones that are constantly duking it out to give you hunger or to make you feel satisfied. In a later post we’ll talk about leptin, but suffice to say that whenever leptin hangs out in your blood, neuropeptide Y doesn’t have any effect.

Further questions

Now, if you’re anything like me, you may be wondering if overweight or obese people secrete more ghrelin than their slimmer counterparts. Perhaps the relationship is the other way around, and some people have higher levels of ghrelin which that causes them to eat more or more often and thus gain weight. At the same time, is it possible for us to develop resistance to ghrelin? I do not have the answer to this questions, but I’ll do a literature review and show you what I’ve found in a later post.

Hope you enjoyed this post, if you would like to see more like it, check out our page on Rebuttals to Fatlogic.

See you next week!