The Hunger Hormone
Ghrelin is a known as the hunger hormone because it stimulates appetite, increases food intake and promotes fat storage. It is produced and released mainly by the stomach and also the small intestine as well as the pancreas and the brain.
Ghrelin has numerous functions. It stimulates the release of growth hormone from the pituitary gland and has also been shown to act on regions of the brain involved in reward processing such as the amygdala.
Ghrelin administered to humans, increases food intake by up to 30%; it circulates in the bloodstream and acts at an area of the brain crucial in the control of appetite the hypothalamus.
It also plays a role in the control of insulin release and has protective effects on the cardiovascular system.
How is ghrelin controlled?
Levels of ghrelin in the blood rise just before eating or when fasting and levels are primarily regulated by food intake. It is thought to play a role in mealtime ‘hunger pangs’.
Different nutrients slow down ghrelin release to varying degrees and eating reduces the concentrations of ghrelin. Carbohydrates and proteins restrict the production and release of ghrelin to a greater extent than fats.
The Satiety Hormone
The satiety hormone Leptin, named by researcher Friedman after the greek word leptos meaning “thin”has been identified after studies firstly on mice, showed that those who did not produce leptin kept eating and they were not able to judge the amount of food consumed. they seemed permanently hungry.