Purina releases results from first life span study

St. Louis-

Nestlé Purina's Life Span Study shows that maintaining a dog's lean body condition extended their median life span by 15 percent.

For the Labrador Retrievers in the study, the statistic translates intotwo years.

The Purina study was begun in 1987 and was completed in 2001. Dr. DennisLawler, who along with fellow Nestlé Purina scientist and principalinvestigator Richard Kealy, Ph.D. headed the research team. "What'sexciting about this study is that, for the first time in a larger mammal,we proved that eating less resulted in longer life. That's pretty powerfulstuff."

Dr. Gail Smith, study collaborator and professor of orthopedic surgeryat the University of Pennsylvania School of Veterinary Medicine, says thestudy constitutes a one-of-a-kind body of work yielding profound benefitsto veterinarians and clients.

"Purina invested 14 years in a scientific study that has alreadyproduced useful clinical information. And with continued analysis of accumulateddata, the study promises to add to the body of scientific literature foryears to come," he says. "The amount of data on canine body systemsis enormous and the impact on the health and quality of life of our patientswill be significant."

The 14-year study was conducted at the Purina Pet Care Center and compared48 Labrador Retrievers from seven litters. The dogs were paired within theirlitters according to gender and body weight and randomly assigned to eithera control or lean-fed group. The control group was fed ad libitum during15-minute daily feedings, while the lean-fed group was fed 75 percent ofthe amount eaten by its paired littermates. All dogs consumed the same 100percent nutritionally complete and balanced diets (puppy, then adult formulations)for the entire period of the study; only the quantity provided was different,the study says.

Dogs were weighed weekly as puppies, periodically as adolescents andweekly as adults. Beginning at 6 years of age, they were evaluated annuallyfor body condition using the Purina Body Condition System, a standard usedby veterinarians to evaluate body physique in pets. Other health indicatorsincluding body fat, lean body mass and bone mass, effective glucose andinsulin use as well as serum cholesterol and triglyceride levels were measuredannually.

Median life span was increased by 1.8 years, or 15 percent, in the lean-feddogs compared to the control dogs. Median life span (age at which 50 percentof the dogs in the group had died) was 11.2 years in the control group comparedto 13 years in the lean-fed group.

By age 10, only three lean-fed dogs had died, compared to seven controldogs. At the end of the 12th year, 11 lean-fed dogs were alive, with onlyone control dog surviving. Twenty-five percent of the lean-fed group survivedto 13.5 years, while none of the dogs from the control group lived to thatage.

In addition, the age when 50 percent of the dogs required treatment fora chronic condition was 12 years among the lean-fed dogs, compared to 9.9years for the control dogs. The lean-fed group had lower serum triglyceridesand triiodothyronine, as well as healthier insulin and glucose use.

"What we have learned from this study is that feeding less doesnot necessarily change what health problems dogs encounter, or what, ultimately,causes their death," Lawler says. "What it does change is whenthis occurs." This observation, he adds, is corroborated by the resultsof restricted feeding research in other species.

Dr. Aine McCarthy, director of professional communications for NestléPurina PetCare, says the study proves that lean dogs live longer and betterlives, yet millions of dogs are overweight and obese.

"Because of the relationship ­ now proven ­ between leanor ideal body condition and good health, the concept of feeding to idealbody condition should be discussed with every pet owner," McCarthysays. "Veterinarians now have a powerful and important message theycan deliver with confidence to their clients ­ along with data to backit up," she adds.