Ghrelin and PYY (peptide YY) are two hormones secreted by the gastrointestinal tract that play a role in regulating appetite. Although ghrelin has an orexigenic effect (stimulates hunger) and is released before eating or during fasting, PYY is an anorexigenic (subdues hunger) hormone that is normally released after meals to promote satiety. Studies on anorexia nervosa (AN) have shown that people with AN have higher levels of both ghrelin and PYY during fasting and after a meal, compared to people without AN, despite not experiencing an increase in appetite as expected with higher ghrelin levels. To investigate the role of these hunger-regulating hormones in underweight people with ARFID, one study from 2021 compared fasting and postprandial (postmeal) levels of ghrelin and PYY in participants with low-weight ARFID or AN and a control group of participants without these conditions.[1]
The study found that participants with low-weight ARFID had lower levels of both fasting and postprandial ghrelin compared to the AN group but had levels similar to those of the control group. Additionally, over 50% of the low-weight ARFID participants showed an earlier postprandial spike of PYY compared to participants without ARFID or AN, which could explain the quick feeling of fullness after starting to eat. Contrary to expectations, the study findings indicated that participants with low-weight ARFID showed an earlier spike in PYY hormone compared to the control participants. These results suggest a potential dysregulation of the PYY hormone in individuals with low-weight ARFID, which may contribute to their low appetite and rapid satiety. [1]
Further investigation is needed to determine whether the differences in PYY and ghrelin levels could serve as biomarkers to differentiate between AN and ARFID and guide appropriate therapeutic interventions. It is important to note that this study had several limitations, including the sample size, age differences among groups, and the lack of data on ghrelin and PYY levels in individuals with low weight but no known health conditions.[1]
References
- ^Becker KR, Mancuso C, Dreier MJ, Asanza E, Breithaupt L, Slattery M, Plessow F, Micali N, Thomas JJ, Eddy KT, Misra M, Lawson EAGhrelin and PYY in low-weight females with avoidant/restrictive food intake disorder compared to anorexia nervosa and healthy controls.Psychoneuroendocrinology.(2021-Jul)