Where it is released from?
Ghrelin, otherwise known as the ‘hunger hormone’, is produced mainly by cells that line the stomach and pancreas. Its release is triggered by hunger for food or an empty stomach.
What is its main function?
Ghrelin and leptin are weight-regulating hormones that work together to maintain homeostasis, by controlling our appetite and hunger signals. Homeostasis is the body's auto-regulation mechanism which allows us to keep a constant stable internal environment; likened to feeling well-balanced and as though our energy levels are at their optimum levels of fluctuation. Ghrelin’s main function is to communicate to the brain when our stomachs are empty. It stimulates appetite, increases food intake and promotes fat storage. When it is released, ghrelin typically updates the brain to let the hypothalamus know that we are hungry - it’s an immediate conversation, whereas with Leptin, regulation happens over longer periods of time dependent on the level of fat content in the body. When we eat, our ghrelin levels decrease and if we’ve not eaten in a while, ghrelin levels are typically higher. Food groups like carbohydrates (mostly whole grains) and proteins can slow down the release of ghrelin, more so than fats.
Other than its role in hunger regulation, ghrelin also has other important functions within the body; it stimulates the release of growth hormone from the pituitary gland, breaking down fat tissue and building up muscle, in the process. It can also have protective effects on the cardiovascular system by strengthening the heartbeat and supporting the flow of blood to the rest of the body.
What are the effects of imbalances in this hormone?
The balanced flow of leptin and ghrelin production in the body helps to maintain healthy hunger cycles. Persistent high levels of ghrelin could be due to a long period of time passing without eating, dieting or fasting. Understandably then, high levels could also be prevalent in those with eating disorders such as anorexia nervosa. The high levels are the body’s way of communicating its lack of fat and its need to be fueled by food. Low levels of ghrelin are more common in those who are overweight or obese. Ghrelin can only decrease slightly once an obese person has eaten a meal, therefore the brain hasn’t received a clear message about the stomach being full. This can encourage overeating and feed into a vicious cycle of potential weight gain and in turn, therefore other health issues. Add any emotional or mental emotional struggles with self-image on top of that, and we begin to understand how weight can be difficult to manage and lead many women into cyclical struggles around weight.
What is its relationship to lifestyle: diet and stress?
Ghrelin release can also be triggered by stress, contributing to why many people may relate to an incessant desire to eat when feeling stressed. The increase in ghrelin and perpetual stress cycle can lead to strong urges to snack or overeat. Ghrelin levels also increase after we’ve been dieting which explains why so many diets are unsuccessful, as many tend to put the weight back on. Dieting culture has been rampant for decades. Slowly but surely, nutrition trends have taken on new shapes with less talk about diet pills and more talk about intuitive eating and food plans that accommodate individual needs. And isn’t it amazing to understand all the intricacies that are at play within the body, responsible for hunger? Not only do we eat to nourish ourselves and as an expression of creativity if we love to cook, but we are also eating in response to fundamental hormonal structures within the body and brain. Communication networks that are intended to keep us at our optimum weight and level of health. Honouring them the best we can by identifying our emotional and mental triggers around food, and the reasons behind wanting to be a certain weight, are good starting points.
Words by Amy Mabin
Read more of our Hormone 101 series: