The findings add to the growing body of evidence that caloric restriction in a wide range of species significantly boosts longevity. Dogs are the only large mammals -- and the closest human relatives -- for which a diet-restriction study has been completed. Similar studies involving primates are ongoing.

The results, from scientists at the University of Pennsylvania School of Veterinary Medicine, Nestle Purina PetCare Company, University of Illinois, Cornell University and Michigan State University, will be the subject of a Sept. 20-21 symposium in St. Louis. Partial results were published in May in the Journal of the American Veterinary Medical Association.

The study involved 48 Labrador retrievers from seven litters. Littermates were paired, with one dog fed 25 percent fewer calories than its sibling starting at 8 weeks of age. The researchers found a median life span of 13 years among dogs whose food intake was reduced, while dogs in the group fed a diet higher in calories were uniformly overweight and had a median life span of 11.2 years.

"Impressive as they are, the life span figures are only part of the story," said Gail K. Smith, professor of orthopedic surgery at Penn and chair of the Department of Clinical Studies at the School of Veterinary Medicine's Philadelphia campus. "The study also showed that lean body conformation forestalls some chronic illnesses, most notably osteoarthritis, and that diet can either mitigate or exacerbate the expression of genetic diseases.

"This study should reinforce for dog owners the importance of keeping their dogs lean, with palpable ribs and an obvious waistline," Smith said. "Avoid giving dogs too many high-calorie treats and consider a br
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Contact: Steve Bradt
bradt@pobox.upenn.edu
215-573-6604
University of Pennsylvania
13-Sep-2002