The paper will be published by Science Express, an online publication of the AAAS, on Feb. 1. Science Express is used for rapid publication of selected research papers that are published later in the print version of Science.
Van Voorhies did the metabolic measurements for the study, using sensitive detectors in his laboratory at NMSU to analyze the aerobic respiration of the tiny flies. Carefully controlling the flow and oxygen content of air flowing to the flies in sealed systems, he can determine the flies' metabolic rates by analyzing the carbon dioxide they give off.
At the cellular level, this metabolic process is essentially the same in all organisms. Fruit flies and other short-lived organisms make useful "model organisms" for studies such as this because studying humans is impractical, Van Voorhies noted.
"If you are studying longevity, by definition the study is going to take longer than the lifespan of the researcher," he said.
Van Voorhies said metabolic studies of the fruit flies showed that longer lifespans in those subjected to caloric restriction were not simply a result of slower metabolism.
"A simple way to get a fruit fly to live longer is to put it at lower temperatures," he said. "It will live longer but everything is going slower in the animal, so you haven't fundamentally altered the way it has aged. So we wanted to make sure the effect of caloric restriction wasn't just slowing the animals down, and we found that it wasn't. You can have a high metabolic rate and be long-lived, and that's an encouraging observation."
Ultimately, understanding any link between human longevity and caloric intake, and the role our sense of smell may play in the process, will require more knowledge of the fundamental mechanisms at work, Van Voorhies said.
Source:New Mexico State University