Effect of Dietary Calcium and Dairy Proteins on the Adipose Tissue Gene Expression Profile in Diet-Induced Obesity

Background/Aims: Calcium and dairy proteins have been postulated to explain why the intake of dairy products correlates inversely with body mass index in several populations. We have shown that a high-calcium diet with whey protein attenuates weight gain and now we describe the effects of this diet on adipose tissue gene expression. Methods: Nine-week-old C57131/6J mice were divided into two groups (n = 10/group). The control diet was a standard high-fat diet (60% of energy) low in calcium (0.4%). The whey protein diet was a high-calcium (1.8%), high-fat diet with whey protein. After the 21-week treatment, adipose tissue transcript profiling (2 mice/group) was performed using Affymetrix Mouse Genome 430 2.0. Results: The high-calcium diet with whey protein altered the expression of 129 genes (+/- 1.2 fold). Quantitative RT-PCR analysis confirmed the significant up-regulation of Adrb3 (p = 0.002) and leptin (p = 0.0019) in the high-calcium whey group. Insulin and adipocytokine signaling pathways were enriched among the up-regulated genes and the fatty acid metabolism pathway among the down-regulated genes. Conclusions: High-calcium diet with whey protein significantly modifies adipose tissue gene expression. These preliminary findings reveal that targets of a high-calcium diet with whey protein include genes for Adrb3 and leptin, and help to explain how the intake of dairy products might attenuate obesity. Copyright (C) 2008 S. Karger AG, Basel