UTRITION RIEF NIssue 4 B KEY POINTS: • Soy is an excellent source of high quality protein. • Soy are plant-based antioxidants which have benefits for overweight and obese dogs. • germ meal is a natural source of soy isoflavones. Soy and Isoflavones: Important Nutrition for Pets The excellent nutrition delivered by soy is often overlooked Soy as a Source of when it comes to pet food diets. This “Nutrition Brief” will address this topic and discuss this ingredient’s Highly Digestible Protein many benefits. Nestlé Purina began research on the The soy proteins in most commercial pet foods topic of soy isoflavones more than 5 years ago, and this have digestibility values comparable, or superior to, newsletter will also present those positive findings. protein from animal sources.1, 2 The apparent digestibility of protein from soy sources in diets of dogs Soy: A High Quality Ingredient has been variously reported as 71% to 90%.3, 4, 5, 6 Soy is an excellent source of protein and carbohydrates. Three isocaloric, isonitrogenous dry dog foods with Whole contain 40% protein. And soybean primary protein sources of either beef and bone germ meal, , concentrate and meal, soybean meal, or a combination of these two ingredients showed no difference in protein soy protein isolate contain 42%, 48%, 65% and 90% 1 protein, respectively. digestibility. Other studies have shown that protein in soybean meal is at least as digestible as beef or poultry Soy is also rich in polyunsaturated fatty acids, very low in meals used in dog foods.2, 7 Based on this data, the saturated fats and contains no cholesterol. In addition, it bioavailability of amino acids from soybean protein is contains calcium, iron, zinc, phosphate and magnesium. comparable to that of protein from animal sources. Protein concentration of common soy ingredients Health Benefits of Soy

100% Many health benefits have been associated with regular consumption of soy products in humans. For 90% instance, soy has been found to reduce the risk of cardiovascular disease and certain types of cancer 80% (breast and prostate cancer in humans); relieve a number of problems in post menopausal women 70 % including hot flashes, osteoporosis, and decline in cognitive function; reduce cholesterol and triglycerides 60 % in plasma; improve symptoms of hypertension, and prevent abdominal fat accumulation.8, 9, 10 50 % Soy has a long history of safe use in both humans and animals, including dogs and cats. On the following 40 % page, you'll discover how soy isoflavones can produce benefits for the health and well-being of pets. 30 %

20 %

10 % 42% 65% 90% WHOLE 48% SOY PROTEIN SOY PROTEIN SOYBEANS SOYBEAN MEAL CONCENTRATE ISOLATE 0 PROTEIN CONCENTRATION NUTRITION BRIEF Issue 4

The Beneficial Role of Isoflavones Isoflavones and Obesity Isoflavones are natural plant-based nutrients which Recognizing the safety of soy and the benefits have beneficial antioxidant properties. Isoflavones can observed in other species, Nestlé Purina began be found naturally in plant sources such as chickpeas studying the benefits of soy isoflavones in dogs and green tea, but they are highest in soy products. more than 5 years ago, using randomized, controlled 11, 12, 15 Soy isoflavones occur naturally in three different studies. Compared to the control diet, the forms: , , and . Soybean -containing diet was found to: germ meal naturally contains high levels of daidzein • Slow body fat accumulation and weight gain in 12 and glycitein, the isoflavones found to be beneficial in overfed dogs. healthy weight management in dogs.11, 12 A research • Help reduce oxidative stress in overweight dogs, which 15 study using ovariectomized rats found that the may help reduce the risk of arthritis and diabetes. • Improve insulin clearance (the Purina Life Span Daidzein, glycitein and estrone reduced Study showed that chronic high blood insulin was weight gain in ovariectomized (OVX) rats associated with certain chronic health problems, such as diabetes).15 10 • Increase energy metabolism (energy expenditure) in 8 neutered male dogs.15 6 Changes in body fat of dogs fed an 4 isoflavone-containing diet or a control diet

2 17 OVX + OVX + OVX + OVX + Control INTACT OVX DAIDZEIN GLYCiTEIN GENISTEIN ESTRONE 0 Isoflavones ABDOMINAL FAT (g/100 g body weight) 12 isoflavones daidzein and glycitein prevented increases in body weight and abdominal fat accumulation.13 7 The level of isoflavones in soybean germ meal is approximately four times the level in soy meal.14, 15 2 0 Comparison of isoflavone content in soybean -3 meal and soybean germ meal Months 3 6 9 12 ISOFLAVONE SOYBEAN MEAL SOYBEAN GERM MEAL CHANGE IN BODY FAT % DAIDZEIN 32% 52% GENISTEIN 66% 17% The safety of soy isoflavones was evaluated during GLYCITEIN 3% 31% long-term testing and no clinical evidence of adverse TOTAL ISOFLAVONES 1490 mg/kg 6260 mg/kg effects were observed, and the isoflavone-containing diet had no adverse effects on thyroid function, blood chemistry, or complete blood counts. References 1. Huber, T.L., D. Laflamme, K.M. Comer, W.D. Anderson. 1994. Nutrient digestibility of dry dog foods containing plant and animal proteins. Canine Practice. 19:11 2. Zuo, Y., G.C. Fahey, Jr., N.R. Merchen, N.L. Bajjalieh. 1996. Digestion responses to low oligosaccharide soybean meal by ileally-cannulated dogs. J. Anim. Sci. 74:2441. 3. Kendall, P.T., D.W. Holme. 1982. Studies on the digestibility of soya bean products, cereal, cereal and plat by-products in diets of dogs. J. Sci. Food Agric. 33:813. 4. Meyer, H. 1980. Nutrient digestibility and its relationship to alimentary disorders in dogs. In: R.S. Anderson (Ed.) Nutrition of the dog and cat. P. 55. Pergamon Press, Oxford. 5. Kendall, P.T., D.W. Holme, P.M. Smith. 1982. Methods of prediction of the digestible energy content of dog foods from gross energy value, proximate analysis and digestive nutrient content. J. Sci. Food Agric. 33:823. 6. Wiernusz, C.J., R.G. Shields Jr., D.J.V. Vlierbergen, P.D. Kigin, R. Ballard. 1995. Canine nutrient digestibility and stool quality evaluation of canned diets containing various soy protein supplements. Vet. Clin. Nutr. 2:49. 7. Bednar, G.E., S.M. Murray, A.P. Patil, E.A. Flickinger, G.C. Fahey, N.R. Merchen. 1998. Selected animal and plant protein source on nutrient digestibility and fecal characteristics of ileal cannulated dogs. Proceedings of 1998 Purina Nutrition Forum, St. Louis, MO. 8. Kritz-Silverstein D, Von Muhlen D, Barrett-Connor E, Bressel MA. 2003. Isoflavones and cognitive function in older women: the Soy and Postmenopausal Health In Aging (SOPHIA) Study. Menopause. 10:196-202. 9. Setchell KD, Cassidy A. 1999. Dietary isoflavones: Biological effects and relevance to human health. J Nutr. 129:758S-767S. 10. Sites C, Cooper B, Toth M, Gastaldelli A, Arabshahi A, Barnes S. Effect of a daily supplement of soy protein on body composition and insulin secretion in postmenopausal women. Fertility and Sterility, 2007 (in press). 11. Pan YL. 2006. Use of soy isoflavones for weight management in spayed/neutered dogs. FASEB J. 20:A854-A855. 12. Pan YL. 2007. Effects of isoflavones on body fat accumulation in neutered male and female dogs. FASEB J. 21:551.20. 13. Uesugi T, Toda T, Tsuji K, et al. Comparative study on reduction of bone loss and lipid metabolism abnormality in ovariectomized rats by soy isoflavones, , and glycitin. Bio Pharm Bull 2001; 24:368-372. 14. USDA-Iowa State University Database on the Isoflavone Content of Foods – 1999. 15. Pan YL. 2007, unpublished data. Questions? Call us at 1-800-222-VETS (8387), 8:00 a.m. to 4:30 p.m. CT, Mon. through Fri. OR visit our website at purinavets.com; username: purinavets; password: nutrition. VET 1871-0208 Trademarks owned by Société des Produits Nestlé S.A., Vevey, Switzerland Printed in U.S.A.