The Effects of Dairy Components on Energy Partitioning and Metabolic Risk in Mice: A Microarray Study

Background/Aim: High-calcium diets modulate energy metabolism and suppress inflammatory stress. These effects are primarily mediated by calcium suppression of calcitriol. We have now investigated the effect of additional components in dairy products [branched-chain amino acids (BCAA) and angiotensin-converting enzyme inhibitors (ACEi)] on adipocyte and muscle metabolism in an animal model of diet-induced obesity. Methods: aP2-agouti mice were fed four different 70% restricted diets for 6 weeks: basal-restricted diet (0.4% Ca), nonfat dry milk (1.2% Ca), calcium-depleted milk (0.4% Ca), or basal-restricted diet (0.4% Ca) with supplemented BCAA/ACEi. A high-density oligonucleotide microarray approach was used to compare the effects on energy metabolism. Results: Lipogenic genes in adipose tissue were downregulated in the milk group while in muscle protein synthetic pathways were stimulated by the Ca-depleted and low Ca/BCAA/ACEi diets. Pathways involved in inflammation were altered in adipose tissue and muscle by all three diet treatment groups. Conclusions: The results support our previous findings that calcium and BCAA contribute to the alteration of energy partitioning between adipose tissue and muscle. They provide further evidence for a calcium-independent effect of BCAA and ACEi in energy metabolism and inflammation. Copyright (C) 2009 S. Karger AG, Basel