Health Scan: Keep your biological clock ticking properly by avoiding fatty food

Researchers say eating a lot of fat and calories can not only make you overweight, it can also knock your biological clock out of adjustment.

By JUDY SIEGEL-ITZKOVICH
health scan 88 (photo credit: )
health scan 88
(photo credit: )
Eating a lot of fat and calories can not only make you overweight, it can also knock your biological clock out of adjustment. So say researchers at the Institute of Biochemistry, Food Science and Nutrition at the Hebrew University's Faculty of Agriculture, Food and Environment in Rehovot. A defective biological clock can lead to sleep disorders, hormone imbalance, obesity, psychological problems and even cancer. Studying mice, Dr. Oren Froy and colleagues made the connection between a high-fat and volume diet and circadian rhythm, the brain mechanism that determines the roughly 24-hour cycle of bacteria, fungi, plants, animals and humans. While light is the strongest factor affecting the circadian clock, Froy and colleagues have demonstrated that diet also matters. To examine this thesis, Froy and Maayan Barnea (a doctoral student) and HU agricultural biochemist Prof. Zecharia Madar tested whether the clock controls the liver's adiponectin signaling pathway and, if so, how fasting and a high-fat diet affect this control. Adiponectin, secreted from differentiated adipocytes (fat tissue) and involved in glucose and lipid metabolism, increases fatty acid oxidation and promotes insulin sensitivity - two important factors in maintaining proper metabolism. The researchers fed mice either a low-fat or high-fat diet, followed by a day of fasting. Then they measured components of the adiponectin metabolic pathway at various levels of activity. In mice on the low-fat diet, the adiponectin signaling pathway components exhibited normal circadian rhythm. Fasting resulted in a phase advance. The high-fat diet resulted in a phase delay. Fasting raised the levels of adenosine monophosphate-activated protein kinase (AMPK) levels, while the high-fat diet reduced them. This protein is involved in fatty acid metabolism, which could be disrupted by the lower levels. In an article to be published by Endocrinology, the researchers suggest that a high-fat diet could contribute to obesity, not only through its high caloric content, but also by disrupting the daily rhythm of clock genes. They also suggest 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 and the sleep/wake cycle. SMOKE AND STROKES MIX If your family has a history of strokes and you smoke, your risk of having a stroke are six times higher than those of a non-smoker, according to a new study in the prestigious journal Neurology.The type of stroke, called subarachnoid hemorrhage, is deadly in about 40 percent of patients. Scientists from the University of Cincinnati in Ohio looked at 339 people who suffered a stroke from a brain aneurysm and 1,016 people who had not had such a stroke. Current smokers made up half the group that had a stroke, while the other half had never smoked or had quit. The study also found that people with a family history of stroke could cut their risk by more than half by quitting smoking. The results were the same regardless of blood pressure, diabetes, alcohol use, body mass index or education level. MOBILE SOLUTIONS When young patients at Ziv Hospital are seen riding around the pediatrics department on tricycles, they are not just having fun; they are also getting infusions. A voluntary organization called the Maggi Foundation, which promotes medical clowning in hospitals around the country, recently donated to the Safed facility two of the special colorful tricycles, which are equipped with an erect metal stand for hanging bags of infusion solutions. As many hospitalized children fear the insertion of a needle for infusions, the sight of the bikes and clowns make them forget their anxiety. In addition, instead of being forced to stay in bed for an infusion, they can ride around and laugh while getting them. So far, 16 medical centers have received such a gift from the foundation. TOY PISTOLS, REALINJURIES Scores of children have suffered serious damage to their eyes from plastic pellets shot at 260 kilometers per hour from toy guns, according to the ophthalmology department at Soroka University Medical Center in Beersheba. Called Airsoft, the guns look like real pistols and shoot hard-plastic, six-millimeter "bullets." They are very popular among children because they are cheap and easy to buy even though they are illegal . In the past three years, the hospital has treated about 60 Negev children with Airsoft injuries; their average age is almost 10 years, while 95% are Beduin and 80% are boys. The typical injury is bleeding and edema of the retina at the back of the eye. The children suffer not only from pain but also from serious vision problems that - fortunately - usually pass with time and proper treatment, which includes bandaging, drugs and complete rest. Dr. Assaf Keretz, a senior ophthalmologist in the department, said the trauma typically causes a ring-like injury to the retina. Such a sign was not identified previously in the medical literature. He and chief of ophthalmology Prof. Tova Lifschitz studied the phenomenon and presented their findings at a conferences of peers in Israel and the US. The showed in special high-speed photographs how damage is caused to the eye when hit by the pellets. Michal Zohar Shimshi, head of the Soroka branch of Beterem (the National Center for Children's Safety and Health), said it is forbidden to produce, import or sell toy pistols that look real - for security as well as safety reasons. However, this law is not enforced, causing needless harm to children.