More on the Neurology of Obesity
The last year has seen a mass of new obesity research linking intestinal hormones and the brain.
Over the last 25 years, there has been increasing evidence that many people with significant weight problems have problems in a region of the brain called the hypothalamus that is involved in the control of appetite, feeding, temperature and a range of other bodily functions. On April 18th, I mentioned the intriguing possibility that viruses could be one previously unrecognized explanation for the obesity pandemic. It is hypothesized that these viruses might alter the normal functioning of the hypothalamus, causing an increase in feeding, and perhaps also of appetite and inactivity.
A study from Albert Einstein Medical College in New York, published in this month’s Journal of Clinical Investigation provides further evidence that there may be something wrong with the normal functioning of the hypothalamus.
We normally have a sensitive mechanism in the hypothalamus for sensing fats, which provide a strong signal to stop eating and also to start normalizing blood glucose. There are strains of obese rats, and in these little creatures the fat sensing mechanisms do not work properly. Not only do they keep eating, but also they cannot control their blood glucose properly. Those two things together conspire to produce yet more obesity. What was so interesting in this study, was that the researchers found that if they inhibited a single enzyme involved in fat metabolism, the levels of fatty acids rose in the hypothalamus, the animals were once again able to sense fat levels, and both their feeding and glucose levels normalized.
This is one of the first times that it has been possible to find a single enzyme that would normalize metabolism. The next question is to see whether this might constitute a viable treatment for obesity, or if the body would quickly work around the treatment and return to its old ways.
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