Original Clinical	Horm Metab Res 2005; 37: 309-315 DOI: 10.1055/s-2005-861475
© Georg Thieme Verlag KG Stuttgart · New York
Soy Protein Influences Insulin Sensitivity and Cardiovascular Risk in Male Lean SHHF Rats
J.  Davis1,2, J.  Steinle2, D.  A.  Higginbotham1,2, J.  Oitker2, R.  G.  Peterson3, W.  J.  Banz1,2
1 Animal Science, Food & Nutrition, Southern Illinois University, Carbondale, IL 2 Physiology, Southern Illinois University, Carbondale, IL 3 Indiana University School of Medicine, Indianapolis, IN

Abstract

Previous investigations have demonstrated a marked effect of soy protein on multiple physiological parameters associated with the metabolic syndrome (MS). This preliminary study investigated the physiological effects of soy-based diets on cardiovascular risk in a unique rodent model that reflects early stages of MS. Briefly, lean male SHHF (+/cp) rats were randomly assigned to the following treatment groups: casein (control, C); low-isoflavone (LIS) soy protein isolate; high-isoflavone (HIS) soy protein isolate; or C+ 0.01 % rosiglitazone (CR). Rats were fed for thirty-six weeks. Liver weight, heart weight, total plasma cholesterol, fasting blood glucose were lower in soy-fed animals compared to control (p < 0.01). Body weight, kidney weight, alanine aminotransferase (ALT), fasting plasma insulin, and homeostasis model assessment (HOMA) score were also lower in LIS-fed rodents (p < 0.05) compared to casein treatment. All diet groups exhibited lower urine protein (p < 0.01) and small arteriole content (p < 0.05) compared to controls. LIS feed had a slightly more profound influence on body weight, liver metabolism, and insulin sensitivity. However, both soy diets exhibited marked improvements over a casein-based diet.

Key words

Soy protein - Rosiglitazone - Metabolic syndrome - Insulin - Cardiovascular disease