Water- and nutrient-dependent effects of dietary restriction on Drosophila lifespan

doi:10.1073/pnas.0908016106

Water- and nutrient-dependent effects of dietary restriction on Drosophila lifespan

^aDivision of Biology, California Institute of Technology, Pasadena, CA 91125; and
^bDepartment of Biology, Long Island University, Brookville, NY 11548

↵³Present address: Harvard University, Cambridge, MA 02138.
↵⁴Deceased November 30, 2007.

Edited by David L. Denlinger, The Ohio State University, Columbus, OH, and approved September 4, 2009
↵²W.W.J. and G.B.C. contributed equally to this work. (received for review July 17, 2009)

Abstract

Dietary restriction (DR) is a widely conserved intervention leading to lifespan extension. Despite considerable effort, the mechanisms underlying DR remain poorly understood. In particular, it remains unclear whether DR prolongs life through conserved mechanisms in different species. Here, we show that, in the most common experimental conditions, lifespan extension by DR is abolished by providing Drosophila with ad libitum water, without altering food intake, indicating that DR, as conventionally studied in flies, is fundamentally different from the phenomenon studied in mammals. We characterize an alternative dietary paradigm that elicits robust lifespan extension irrespective of water availability, and thus likely represents a more relevant model for mammalian DR. Our results support the view that protein:carbohydrate ratio is the main dietary determinant of fly lifespan. These findings have broad implications for the study of lifespan and nutrition.

Footnotes

¹To whom correspondence should be addressed. E-mail: billja{at}its.caltech.edu
Author contributions: W.W.J., G.B.C., B.M.Z., T.B., and S.B. designed research; W.W.J., G.B.C., B.M.Z., and E.M.M. performed research; W.W.J., G.B.C., and B.M.Z. analyzed data; and W.W.J. and G.B.C. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
↵* Although water is commonly considered a nutrient, we use this term to refer to all nonwater food components (e.g., yeast and sugar) throughout the text.
This article contains supporting information online at www.pnas.org/cgi/content/full/0908016106/DCSupplemental.