Body clock implicated in obesity
New research presented at the Forum of European Neuroscience (FENS 2006) suggests that the body's own internal clock may cause many common diseases, from high blood pressure to insulin resistance and obesity Dr Ruud Buijs of the Netherlands Institute for Brain Research believes that defects to the body's internal clock may be responsible for 'metabolic syndrome', which can affect the heart and cardiovascular systems, with common symptoms including obesity, insulin resistance and high blood pressure. Surveys conducted in the US suggest that up to one in four people may be affected with metabolic syndrome. The internal body clock allows humans and other animals to measure time. This is extremely important in regulating when food should be eaten, how long animals hibernate for and how long we sleep for. The body clock also regulated the activity levels of our internal organs, often referred to as metabolism. In humans, the area responsible for the body clock is found in the suprachiasmatic nucleus (SCN), located in the brain, behind the eyes, but other than its role as the body clock, its role is mysterious. Dr Buijs and his team examined the relationship between the SCN, and another area, the arcuate nucleus, responsible for regulating hunger signals. The arcuate nucleus monitors nutritional levels, by keeping tabs on levels of glucose, fatty acids and hormones like insulin. 'We investigated the relationship between arcuate nucleus and SCN by means of tracer studies that revealed the reciprocal relationship between two,' said Dr Buijs. 'We investigated the influence of circulating hormone on the activity of the SCN and found it changed together with the activity of the arcuate nucleus,' said Dr Buijs, suggesting that the two regions are intimately connected. Dr Buijs' team used chemical tracers to follow communication pathways, linking the two areas. Hormones found to act on the arcuate nucleus have also been linked to obesity. If your body cannot tell when it is 'full', then you could continue to eat, making you obese. 'A large study on sleep behaviour revealed a positive relationship between sleeping too much or too little and developing obesity and cardiovascular disease,' said Dr Buijs. 'More and more evidence is accumulating to suggest the metabolic syndrome is a disease of the brain.' Such findings could influence the way certain diseases, like obesity or high blood pressure, are treated, linking them to disorders of the body clock. However, this new finding may work the other way: 'On the other hand, it's possible that recent changes in our lifestyle, with less activity during the day and more food intake during night hours, have had disturbing influence on the biological clock,' says Dr Buijs, leaving the traditional methods of healthy diet to combat cardiovascular disorders and obesity very much open. Dr Bujis and his team have shown that the SCN may not be the 'master clock' it has been thought to be, and rather plays a more holistic role within the body. Further research will highlight ways in which diseases of the metabolism could be better understood.
Countries
Austria, Netherlands