Circadian Rhythms and Eating Disorders

 Many organisms undergo physical, mental, and behavioral changes that follow a 24-hour cycle, known as circadian rhythms. These internal clocks help carry out important functions such as a sleep-wake cycle, but circadian rhythms are also quintessential in the body’s feeding rhythms which arise in the active phase of one’s sleep-wake cycle. This same mechanism also induces fasting during sleep. When examining the eating patterns of someone with a diagnosed eating disorder such as anorexia nervosa, binge eating disorder, or even night eating syndrome, circadian rhythms could play an essential role in the development of these disorders. 

In “Sleep and Circadian Rhythm Disturbances in Eating Disorders”, scientists examine the correlation between circadian rhythms and eating disorders, based on the hypothesis of feeding-fasting disruption being altered by neuroendocrine circadian profiles. This was done by comparing and contrasting previously published work about the relevant topics. The food clock in the brain regions and peripheral tissue are reset to be entrained whenever a meal is expected. This is done via metabolic hormones that synchronize to the food clock that can either promote or inhibit anticipation, this secondary clock works in accordance with the master clock in the SCN which controls sleep-wake through external cues such as light. According to the researchers, because these clocks are intrinsically linked, “This dysregulation of circadian rhythm leads to alterations in the circadian rhythmicity of metabolic parameters and thus disruption in feeding behaviors,” (Kim et al., 2020). Adversely, “Food consumption at usual resting time—nighttime for humans—can desynchronize the circadian pattern and lead to circadian dysregulation,”(Kim et al., 2020). These scientists concluded that the chain of disturbances in the feeding-fasting cycle disrupts metabolism and therefore mood and behavior which are common in individuals with eating disorders.

Research done by scientists at Loyola University also contributes to the idea that disruption of molecular clocks plays a role in feeding patterns through their work done on Drosophila melanogaster, or fruit flies. According to the paper, “Central and Peripheral Clock Control of Circadian Feeding Rhythms”, simultaneous disruption of both the central and peripheral clocks done via dissections, “...significantly dampened feeding rhythms and decreased total liquid food interaction time. These results demonstrate an important contribution of peripheral clocks to feeding behavior…,” (Fulgham et al., 2021). 

Though both studies were vastly different in their methodology, they relate to the subject of peripheral clocks' influence on feeding-fasting mechanisms and therefore, eating disorders. The research done at Loyola on a smaller scale could help determine the broader implications of the subject, such as the analysis done by scientists at Korea University. 

Works Cited

Kim, Sojeong, and Heon-Jeong Lee. “Sleep and Circadian Rhythm Disturbances in Eating Disorders.” Chronobiology in Medicine, https://www.chronobiologyinmedicine.org/m/journal/view.php?number=60. 

Fulgham CV;Dreyer AP;Nasseri A;Miller AN;Love J;Martin MM;Jabr DA;Saurabh S;Cavanaugh DJ; “Central and Peripheral Clock Control of Circadian Feeding Rhythms.” Journal of Biological Rhythms,U.S. National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/34547954/.