A new mouse study suggests that a brain system that controls the sleep/wake cycle might also play a role in regulating appetite and metabolism. Mice with a mutation in a gene called "Clock," which helps drive circadian rhythm, ate significantly more and gained more weight.
The finding could help explain why disrupted sleep patterns-particularly when combined with a high-fat diet--are associated with excessive weight gain and the onset of metabolic syndrome in some people, according to investigators supported by the National Institutes of Health (NIH).
The study, by Fred W. Turek, Ph.D., and Joseph Bass, M.D., Ph.D., of Northwestern University in Evanston, Ill., is available at the Science Express website.
The National Institute on Aging (NIA), the National Heart, Lung and Blood Institute (NHLBI), and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) supported this work. The NIA, NHLBI and NIDDK are components of the NIH at the U.S. Department of Health and Human Services.
At least 40 million Americans have chronic sleep problems, and an additional 20 million experience occasional sleeping problems. As many as 47 million Americans have metabolic syndrome, a cluster of conditions shown to increase a person's risk of heart disease and stroke. The National Cholesterol Education Program defines metabolic syndrome as having at least 3 of the following risk factors: high blood pressure, high glucose (sugar) levels which can indicate risk for diabetes, high triglyceride levels, low levels of good cholesterol, and a large waist.
Scientists have found that circadian rhythms (which control the sleep/wake cycle and other biological processes), hunger, and satiety are all regulated by centers within a brain structure called the hypothalamus. And previous studies in humans have suggested that disrupted sleep patterns may contribute to the development of obesity, diabetes, and metabolic syndrome.