Friday, January 02, 2009

High-Fat Diet Can Disrupt Biological Clock

A high-fat diet not only can lead to overweight, but can also affect the balance of circadian rhythms, according to researchers at Hebrew University of Jerusalem.

In an article to be published in Endocrinology, researchers suggest that a high-fat diet could contribute to obesity, not only through its high caloric content, but also by disrupting the phases and daily rhythm of clock genes. They contend also that high fat-induced changes in the clock and the adiponectin signaling pathway may help explain the disruption of other clock-controlled systems associated with metabolic disorders, such as blood pressure levels and the sleep-wake cycle.

While light is the strongest factor affecting the circadian clock, Oren Froy, PhD, and his colleagues of the Institute of Biochemistry, Food Science and Nutrition at the Hebrew University's Robert H. Smith Faculty of Agriculture, Food and Environment in Rehovot, have demonstrated in their experiments with laboratory mice that there is a cause-and-effect relation between diet and biological clock imbalance.

Researchers tested whether the clock controls the adiponectin signaling pathway in the liver and, if so, how fasting and a high-fat diet affect this control. Adiponectin is secreted from differentiated adipocytes (fat tissue) and is involved in glucose and lipid metabolism. It increases fatty acid oxidation and promotes insulin sensitivity, two highly important factors in maintaining proper metabolism.

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