Researchers close in on aging solution

It is sometimes remarked that abstinence doesn't make you live longer - it only seems like it. The effect is, in fact, real: reducing the intake of food prolongs life in creatures as diverse as bacteria, flies and presumably humans. 

Caloric restriction, as the life-prolonging phenomenon is called, is related to the activity of enzymes known as sirtuins. The more active the sirtuins in an isolated cell - whether from a yeast or a human - the longer the cell will survive and thrive.  

In a report in this week's issue of the research journal Nature, David Sinclair of Harvard Medical School, Boston, Mass., and colleagues establish the link between sirtuins and ageing in whole animals, and open an intriguing possibility - that it might be possible to prolong lives without restricting nutrient intake. 

Chemicals called sirtuin-activating compounds (STACs) exist that pep up the activities of sirtuins, even in the absence of caloric restriction. Sinclair and colleagues report that STACs activate sirtuins from the roundworm Caenorhabditis elegans and the fruit fly Drosophila melanogaster, and extends the lifespans of these animals without reducing fecundity. Lifespan extension is dependent on the presence of a type of sirtuin called Sir2, according to the authors, and is not observed when nutrients are restricted.