Ghrelin and EDs
What is Ghrelin?
Have you ever thought about what makes your stomach growl? Or what makes you feel full after eating? These physical sensations are the result of complex pathways in the body, which are regulated by hunger and satiety hormones. Ghrelin is one of the main hormones associated with this process, otherwise known as the hunger hormone. It works to increase one’s appetite, stimulating food intake.
Ghrelin is produced mostly in the stomach, and helps with the digestive process by increasing gastric acid production, increasing the speed at which food moves through the stomach and empties into the small intestine. These are all crucial components of digestion, and ghrelin helps prepare the body to do so before a meal is consumed. When the body is in a starved state, there are increased levels of ghrelin released into the bloodstream, followed by decreased levels after a meal. When looking at ghrelin levels after a meal, it seems to be dependent on the caloric content of a meal.
Ghrelin levels and Anorexia Nervosa
Some alterations in ghrelin levels, before and after meals, have been seen with various health conditions. For example, ghrelin levels seem to be higher when the body is in a period of fasting and has low energy stores. This could be related to prolonged starvation that is seen in Anorexia Nervosa (AN). The current research has explored the relationship between ghrelin and body weight/BMI. Although we are aware that body weight and BMI is not the only predictor of disease state, this is where the literature currently stands.
When comparing AN individuals to normal weight individuals, studies show there is a correlation between higher ghrelin levels and low body weight/BMI. Plasma ghrelin is higher in the AN individuals in the morning (when fasting) and remains higher after eating and throughout the day. When individuals with AN underwent treatment and regained 25% of their BMI, ghrelin levels seemed to normalize again. On the contrary, in higher weight individuals, ghrelin levels are seen to decrease and are generally lower when fasting.
Other studies have used body adiposity as opposed to BMI as an indicator of nutritional status when looking at ghrelin levels. For example, one study compared individuals with low body weight and AN to people of similar body weight without AN. Ghrelin levels in people with AN were higher than those without when fasting and after eating. This leads to the idea that ghrelin levels could be related to body adiposity, and ghrelin levels are higher when disordered eating is seen.
So what does this mean?
To summarize, there is an inverse relationship between ghrelin and BMI, which means ghrelin could be seen as a marker of nutritional status.2 Oftentimes when living with an ED, physical hunger and satiety cues are skewed, and identifying these signals becomes difficult. The body is constantly working to adapt. The hormones are reacting to normalize the body’s nutritional status and finding a weight where the body can live comfortably. This is when ghrelin levels seem to normalize. As a person progresses through the recovery journey, they will relearn how to identify hunger and satiety signals. These signals are the gut hormones such as ghrelin and many others working to bring the body back to homeostasis.3
Sources:
Atalayer D, Gibson C, Konopacka A, Geliebter A. Ghrelin and eating disorders. Prog Neuropsychopharmacol Biol Psychiatry. 2013 Jan 10;40:70-82. doi: 10.1016/j.pnpbp.2012.08.011. Epub 2012 Aug 30. PMID: 22960103; PMCID: PMC3522761.
Soriano-Guillén L, Barrios V, Campos-Barros Á, Argente J. Ghrelin levels in obesity and anorexia nervosa: Effect of weight reduction or recuperation. The Journal of Pediatrics. 2004;144(1):36-42. doi:10.1016/j.jpeds.2003.10.036
Tribole E, Resch E. Intuitive Eating: A Revolutionary Program That Works. New York: St. Martin's Griffin; 2012.
