SCIENCE OF AGING

March 2005
		Scientists have isolated a series of genes found in many different plants and animals that seem to control the aging process. Two leading scientists on the study of these anti-aging genes -- Dr. Stephen Helfand of the University of Connecticut and Dr. David Sinclair of Harvard Medical School -- answer your questions about their research. Special Report: Science of Aging

Forum Introduction What kinds of food should we eat to exploit this finding? Is there any connection between this work and the theories on telomeres? How many years away are we from human trials? Is it likely that drinking red wine, eating grapes or taking resveratrol in the form of supplements can slow down aging? Aren't there negative side effects from being kept in a state of constant emergency mode? What should the caloric intake for humans be to potentially extend health and life? How does expending calories through exercise affect the rate of aging?	Craig of Los Angeles, Calif. asks: What should the caloric intake for humans be -- compared to that in the rodent studies -- to potentially extend health and life? Dr. David Sinclair responds: CR (calorie restriction) works to delay aging of yeast, worms, flies, dogs and monkeys, and if it doesn't work on humans we would be the biological exception -- and we've been through such discussions before in history. In biology, the drive for survival is universal -- whether you are a rat or a human or even a yeast cell. Species that failed to survive are no longer on the planet. Why does CR work on such diverse organisms? We think that CR provokes an evolutionarily ancient defense response that promotes survival during adversity. During harsh times, it doesn't make sense to reproduce as fast as possible. Instead it is far better to hunker down and defend your body so you will make it to better times. Better bodily defense, better health and longer life. These "longevity" genes are actually ancient survival genes. Biological organisms are incredibly complex, which means that to survive adversity many processes need to be repaired and maintained at once. A billion years ago it seems there was a strong selective force for a universal regulator of this response. This we believe is SIR2. Today SIR2 genes are found in all organisms, ranging from plants, to yeast to humans. Deleting SIR2 from simple organisms like flies prevents CR from working and adding extra copies of SIR2 extends life span by a manner resembling CR. Experiments in mice are ongoing. Dr. Stephen Helfand responds: The rodent models suggest that a reduction of 40-50 percent provides a nearly 50 percent extension of life span. Since we do not yet know if calorie restriction in humans will "extend health and life" this is still an open question.