There is increasing evidence in humans and other species to suggest that nutritional changes can delay aging and/or prevent disease progression. In this study, 3 groups of senior cats were fed 3 different foods formulated to test the hypothesis that dietary manipulation can have a beneficial effect on longevity of aging cats and possibly prevent disease. Three groups of 30 cats aged 7 to 17 were included in this 5-year study. Cats were fed 1 of 3 foods. The first was a basal control diet that was complete and balanced for cats; the second was a basal diet with added vitamin E and beta-carotene; the third diet was a basal diet with vitamin E, beta-carotene, dried whole chicory root (a source of prebiotic), and a blend of supplemental n-3 and n-6 fatty acids. Data were collected before the start of the study and periodically throughout the 5-year period and included CBC, serum chemistry panels, plasma fatty acids, serum antioxidants, fecal microflora, urinalysis, body composition, body scoring, and physical examination. Cats were fed the test foods for 5 years or until death. Cats fed the third diet lived significantly longer (approximately 1 year) than those fed the second diet. All cats lost weight while eating the test food. Cats fed the third diet had significantly higher amounts of Bifidobacteria and significantly decreased amounts of Clostridium perfringens in their feces-in other words, cats fed the third diet had healthier gut flora than those fed chicory-free foods. Cats fed the third diet also had significantly higher levels of vitamin E, beta-carotene, and plasma linoleic acid than those fed the control diet, as well as a significantly decreased incidence of thyroid hyperplasia and adenomas. Only 14% of cats were hyperthyroid compared with 43% of cats fed the first diet. Similar trends were seen with gastrointestinal diseases. The authors concluded that dietary changes can positively affect longevity in senior cats and decrease age-related disorders. Study conducted and funded by Nestle-Purina Research and Development.

COMMENTARY: This is the first published study that attempts to answer a question asked by many small animal practitioners: "Will supplementation of a complete and balanced diet with antioxidants, fatty acids, and/or a prebiotic benefit clinically healthy elderly cats?" In this prospective masked study, 90 research cats older than 7 years were blocked into 1 of 3 groups and fed either a control diet or 1 of 2 supplemented diets ad libitum for 5 years. Diet was not altered when a disease state was diagnosed. Cats fed the diet enriched in antioxidants, long-chain polyunsaturated fatty acids, and a prebiotic had reduced incidence of thyroid disease, reduced rate of weight loss, altered gastrointestinal microflora, and longer lifespan than those eating the control diet. These preliminary findings provide food for thought and suggest that specific nutritional modification for older cats may improve longevity.

Effect of nutritional interventions on longevity of senior cats. Cupp CJ, Philippe C, Wendell WK, et al. INTL J APPL RES VET MED 4:34-50, 2006.