The biggest obstacle to the successful treatment of obesity is the tendency to regain weight lost through diet and exercise,and evidence is increasing that this could be due to physiologicalcauses. Recently, an Australian study reported that after large weight loss, appetite-regulatinghormones appear to reset to levels that increase appetite. Now a new study reported online on 27 December in the Journal of Clinical Investigation , offers further evidence. Senior author Dr.
Michael W. Schwartz,professor of medicine at the University of Washington, andcolleagues, report how rodents and humans with diet-induced obesityhave structural changes in an area of the brain that regulatesweight control. The hypothalamus is a small, pearl-sized area of the brain thatcontrols a large number of body functions, including body weight , which is regulated by a complex set of interactions betweenhormones and neurons or brain cells. There is a growing beliefamong scientists that these interactions, in most obese people,"conspire" to prevent permanent weight loss, and the underlyingmechanisms are increasingly becoming the object of intenseinvestigation by neuroendocrinologists.
Schwartz told the press: "To explain a biologically elevated body weight 'set-point',investigators in the field have speculated about the existence offundamental changes to brain neurocircuits that control energybalance. Our findings are the first to offer direct evidence ofsuch a structural change, and they include evidence in humans aswell as in mice and rats." Schwartz and colleagues looked at what high-fat diets did to thebrains of mice and rats engineered to become obese on such diets. They found that quite early in their lives, the rodents developedlasting brain injuries in a specific part of the hypothalamus (thehypothalamic arcuate nucleus). Using brain scans, they foundsimilar injuries in the same area of the brain of obese humans: "Consistent with these data in rodents, we found evidence ofincreased gliosis in the mediobasal hypothalamus of obese humans,as assessed by MRI," they write.
Schwartz, who holds the Robert H. Williams Endowed Chair inMedicine in the Division of Metabolism, Endocrinology and Nutrition , pointed out that these findings do not prove a cause and effect:that is they can't say for sure that the brain injury is the reasonthe body appears to defend a higher body weight, that has yet to beproved, but: "... this amounts to solid evidence of a change affecting the keyhypothalamic area for body weight control with the potential toexplain the problem," he added. In another study in the same issue of the journal, a second team ofresearchers, led by senior author Dr Jeffrey Flier, of Beth IsraelDeaconess Medical Center, Boston, reports finding that turnover ofnerve cells in the hypothalamus of mice is inhibited by obesity,adding further weight to the argument that physiology, rather thanlapsing back to old eating habits, could be the reason for weightregain following a period of successful weight loss in obesepeople.
Written by Catharine Paddock PhD Copyright: Medical News Today Not to be reproduced without permission of Medical News Today Additional References Citations. I am a professional writer from Chemical Additives, Auxiliary, which contains a great deal of information about cat5 video extender , 1000ft cat5e cable, welcome to visit!
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