BENEFITS FROM CALORIC RESTRICTION: Is It Hormesis?

Edward J. Calabrese



INTRODUCTION

The topic of caloric restriction and its implications for toxicological testing and the risk assessment process has become one of the most dominant issues in toxicology. This is evident by the spate of conference symposia, private-sector and governmental interest and expanded research agenda on the multi-faceted aspects of this topic. Most recently, in fact, the Society of Toxicology devoted an entire issue (Toxicological Sciences, Volume 52, Number 2, Suppl., December 1999) to the "Role of Diet and Caloric Intake in Aging, Obesity, and Cancer". In 1998 Edward J. Masoro, a leading researcher in the area of caloric restriction, proposed that the physiological adaptations associated with caloric restriction leading to lifespan extension were a manifestation of hormesis (Masoro, E.J., 1998, Hormesis and the Antiaging Action of Dietary Restriction, Experimental Gerontology, 33:61-66). Since the BELLE Newsletter has focused considerable attention on the concept of hormesis, it was appropriate that the linkage between hormesis and processes associated with caloric restriction be explored in greater depth by recognized experts in these two fields. Consequently, this issue of the BELLE Newsletter explores that relationship within the context of a detailed debate by such experts. Dr. Ron Hart of the National Center for Toxicological Research, was invited to develop a white paper on this topic (see lead paper by Turturro, Hass, Hart). This paper was independently responded to by experts in either caloric restriction or hormesis. Turturro et al. were then allowed the opportunity to respond to the expert commentary. The results of this debate follow.