Dr. Ron’s Research Review – June 20, 2012

This week’s research review focuses on nighttime eating disorders.

Despite a lack of food intake, serum glucose levels are adequately maintained throughout the sleep period, and both sleep and circadian phenomena operate to help maintain glucose homeostasis. The majority of the decrease in glucose utilization is related to the decline in brain metabolism. The sleep period is also characterized by impairment in glucose tolerance through sleep and circadian mechanisms.

Insulin disposal and growth hormone (GH) secretion help maintain stable glucose levels throughout the sleep period. Sleep deprivation suppresses GH secretion until sleep is initiated regardless of the circadian period. Sleep-onset GH secretion is also associated with increasing density of slow wave sleep.

Leptin, a peptide hormone secreted by adipocytes, mediates satiety by inhibiting hunger centers in the hypothalamus. Leptin has a nocturnal rise that correlates with sleep onset. Conversely, the hormone ghrelin has increased levels during sleep in humans.

Night eating syndrome (NES) is described as evening hyperphagia, nocturnal eating and morning anorexia. NES is frequently familial and often associated with underlying mood disorders such as depression.

Sleep-related eating disorder (SRED) is characterized by recurrent episodes of eating after an arousal from nighttime sleep with adverse consequences.

Central nervous system (CNS) serotonin modulation may lead to an effective treatment of NES, while dopaminergic therapy is preferred for sleep-related eating disorder (SRED). (Howell, Schenck et al. 2009)

Dr. Ron


Article

A review of nighttime eating disorders

            (Howell, Schenck et al. 2009) Download

Nighttime eating is categorized as either night eating syndrome (NES) or sleep-related eating disorder (SRED). These conditions represent an interruption in the overnight fast that characterizes human sleep. A critical review of the literature on NES and SRED will suggest that they are situated at opposite poles of a disordered eating spectrum. NES could be considered an abnormality in the circadian rhythm of meal timing with a normal circadian timing of sleep onset. Conversely, the feeding behavior in SRED is characterized by recurrent episodes of eating after an arousal from nighttime sleep with or without amnesia. Both conditions are often relentless and chronic. Multiple definitions of night eating have limited our ability to determine the exact prevalence of NES. Studies have suggested that central nervous system (CNS) serotonin modulation may lead to an effective treatment of NES. SRED is frequently associated with other sleep disorders, in particular parasomnias. Early studies have shown that the anti-seizure medication topiramate may be an effective treatment for SRED.

References

Howell, M. J., C. H. Schenck, et al. (2009). "A review of nighttime eating disorders." Sleep Med Rev 13(1): 23-34.