Author: Jessica Lear
Institution: West Virginia University
Date: October 2010
In the July 28th issue of The Journal of Neuroscience, new information was released regarding the correlation between the brain, low-calorie diets, and a longer lifespan. The study, involving a protein called SIRT1, was conducted by Shin-ichiro Imai, a Professor of Biology at Washington University in St. Louis.
SIRT1 is a protein that has previously been linked to determining lifespan. With the use of two groups of fasting mice, one with normal SIRT1 levels and one with high SIRT1 levels, Imai was able to find evidence that SIRT1 could help animals survive when food is scarce.
SIRT1, a protein found in every organism, assists the body in using energy more efficiently. It is activated when food, and thus energy, is scarce. Scarce food means fewer calories, and low-calorie diets have already been linked to increasing lifespans. Thus, SIRT1 has an important function during the process of aging. Akiko Satoh, a postdoctoral researcher explains its significance by saying, "This is the first time that it has been demonstrated that SIRT1 is a central mediator for behavior adaptation to low-calorie conditions."
According to the study, mice that were placed on a low-calorie diet showed larger amounts of SIRT1 in specific regions of the hypothalamus. The hypothalamus is the area of the brain that is responsible for basic regulation such as body temperature and hunger. Results from the study also elucidated how transgenic mice that continually produced SIRT1 in the hypothalamus were extremely active even after a two day fast.
With this study, Imai has been able to link SIRT1 to increased activity when a low-calorie diet is introduced. He referenced the "lifespan-increasing effect of low-calorie diets," which has already been discovered in previous studies. By doing so, Imai has demonstrated that SIRT1 plays an important role in determining the life span of an organism. Currently, Imai's lab has expressed interest in monitoring whether the mice with great amounts of SIRT1 will outlive those with normal SIRT1 levels.
Author: Jessica Lear
Reviewed by: Karuna Meda and Yangguang Ou