Skim milk powder enhances trabecular bone architecture compared with casein or whey in diet-induced obese rats

• Published in: Nutrition (Burbank, Los Angeles County, Calif.) Vol. 28; no. 3; pp. 331 - 335
• Main Authors: Fried, Aviv, M.Sc, Manske, Sarah L., Ph.D, Eller, Lindsay K., Ph.D, Lorincz, Caeley, Ph.D, Reimer, Raylene A., Ph.D., R.D, Zernicke, Ronald F., Ph.D., D.Sc
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.03.2012; Elsevier; Elsevier Limited
• Subjects: Absorptiometry, Photon; Animals; bioactive properties; Biological and medical sciences; Body Composition - drug effects; body fat; Bone and Bones - drug effects; Bone and Bones - metabolism; Bone architecture; Bone Density - drug effects; Bones; Calcium; Calcium, Dietary - administration & dosage; casein; Caseins - administration & dosage; Computed tomography; Dairy proteins; Diet; dried skim milk; dual-energy X-ray absorptiometry; energy density; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; Gastroenterology and Hepatology; ingredients; Male; MicroCT; Milk; Milk - chemistry; Milk - metabolism; milk consumption; Milk Proteins - administration & dosage; Obesity; Obesity - chemically induced; Obesity - metabolism; protein sources; protein structure; Proteins; Rats; Rats, Sprague-Dawley; Rodents; tibia; tomography; Tomography, X-Ray Computed; Vertebrates: anatomy and physiology, studies on body, several organs or systems; weight gain; Weight Gain - drug effects; whey; whey protein; Whey Proteins; Dairy proteins; Bone architecture; MicroCT; Obesity; Calcium; Rat; Rodentia; Nutrition disorder; Whey; Powder; Protein; Feeding; Osteoarticular system; Vertebrata; Mammalia; Casein; Diet; Animal; Bone; Nutritional status; Comparative study; Milk
• ISSN: 0899-9007; 1873-1244
• DOI: 10.1016/j.nut.2011.07.022

Abstract Objective We previously showed that skim milk powder (SMP) prevents weight gain more so than casein or whey alone. Dairy foods and changes in body mass can affect bone architecture; therefore, our objective was to examine the effect of dairy proteins on bone structure in the tibia of dietary-induced obese rats. Methods Twelve-week-old diet-induced obese Sprague-Dawley rats were randomized to one of six diets that varied in protein source (casein, whey, or SMP), Ca level (0.67% or 2.4%), and energy density (high-fat/high-sucrose [HFHS], or normal energy density [NE]). After 8 wk, body composition was assessed via dual energy x-ray absorptiometry and trabecular and cortical bone parameters of the tibia were assessed using micro-computed tomography and mixed model analysis. Results Rats fed SMP with 2.4% calcium had significantly lower body mass and fat mass than all other groups. The ratio of bone volume to total volume (BV/TV) was significantly higher when the HFHS diet was supplemented with SMP and 2.4% calcium compared with whey (+66.7%) or casein (+32.6%). The HFHS diet group had 49.3% greater BV/TV compared with the NE groups. Increasing the amount of calcium resulted in a significant increase in BV/TV (188.9%) in the HFHS diet groups but not in the NE groups. Conclusion The intake of skim milk powder supplemented with calcium enhances trabecular bone architecture in obese rats consuming HFHS diet to a greater extent than with either casein or whey protein alone. Bioactive ingredients in complete dairy may contribute to these effects.