In the Literature: New and Noteworthy Nutrition Research

In the past few decades, Americans have been eating more and sleeping less, and some researchers now suspect that there may be a connection. A number of cross-sectional and longitudinal cohort studies have suggested that chronic sleep deprivation is associated with an increased risk of obesity. 1-4It is thought that sleep deprivation may promote weight gain by altering sympathetic nervous system activity or by affecting serum levels of hormones involved in energy metabolism, such as insulin and cortisol. Leptin, an antiobesity hormone secreted primarily by adipocytes, and ghrelin, a hunger-inducing peptide produced by gastric cells, may also be affected by sleep deprivation. In one cohort study involving over 1000 individuals, sleep duration was positively associated with serum leptin concentration and negatively associated with serum ghrelin concentration.4 In keeping with this epidemiologic evidence, one small clinical trial involving healthy volunteers suggested that total sleep deprivation leads to a marked diminution of the diurnal amplitude of leptin. '; A recent study by Spiegel et al.6 explored the complex and intriguing relationship among sleep deprivation, hormones, and appetite. Using a randomized