| RESEARCH | IN THE LAB, one of the most powerful ways to extend life is to reduce food intake while satisfying nutritional needs. Organisms ranging from yeast to mammals enjoy much longer and healthier lives if they consume just two-thirds of the calories they normally eat. Experiments with rodents, for instance, have increased life span by 50% through dietary restrictions. The National Institute on Aging is now sponsoring a trial to test whether humans can stick with this kind of dietary regimen. Fortunately, cutting back on calories may not require a lifelong commitment. Mice whose caloric intake isn't reduced until they are 19 months old--equivalent to late middle age in humans--still show significant life span and health benefits after just a couple of months on the new diet, according to author. Mice that start the diet late show many of the same gene expression changes in the liver that characterize mice on a long-term restricted diet. Affected genes include those associated with metabolism, signal transduction, growth factors, immune response, inflammation, and stress response. On the other hand, the genomic profile of mice that are initially raised on a restricted diet and then switched to a normal diet quickly reverts to resembling that of better fed mice. Author s findings contradict those from earlier studies of late-life calorie restriction. In fact, he notes on his website that his results "go against prevailing theories that say slow, incremental changes in gene expression and metabolism are the cause of aging. They suggest that the key genomic effects of caloric restriction are rapid, readily reversible, and do not seem to result from the long-term accrual of irreversible molecular damage." |
|
Want more information ? Interested in the hidden information ? Click here and do your request. |