The effect on adipose tissue blood flow of isoenergetic meals containing different amounts and types of fat.

OBJECTIVE: To investigate the factors regulating the increase in adipose tissue blood flow following meals. DESIGN: Eight subjects were fed three isoenergetic meals; two high-fat meals rich in either saturated or polyunsaturated fatty acids and one low-fat, high-carbohydrate meal. MEASUREMENTS: Blood samples were taken and adipose tissue blood flow was measured before and for 6 h after the meal. Plasma glucose, insulin, non-esterified fatty acid, total and chylomicron-triacylglycerol and catecholamine concentrations were measured. RESULTS: Adipose tissue blood flow rose to a peak after all three meals (P<0.05 for each). The three meals stimulated adipose tissue blood flow at similar times. There was a marked and statistically significant similarity in the time course of changes in blood flow and insulin concentrations. In contrast, noradrenaline concentrations peaked later than adipose tissue blood flow (P=0.014). CONCLUSION: Adipose tissue blood flow may be 'carbohydrate-stimulated' rather than 'fat-stimulated', with insulin having a vasodilatory role in adipose tissue as in skeletal muscle

High-Amylose Resistant Starch Increases Hormones and Improves Structure and Function of the Gastrointestinal Tract: A Microarray Study

BACKGROUND/AIMS: Type 2 resistant starch from high-amylose maize (HAM-RS2) is associated with increased fermentation, increased expression of proglucagon (gene for GLP-1) and peptide YY (PYY) genes in the large intestine, and improved health. To determine what other genes are up- or down-regulated with feeding of HAM-RS2 a microarray was performed. METHODS: Adult, male SD rats were fed one of the following three diets for a four week study period: cornstarch control (CC, 3.74 kcal/g), dietary energy density control (EC, 3.27kcal/g), and 30% HAM-RS2 (RS, 3.27 kcal/g). Rat microarray with ∼27,000 genes and validation of 94 representative genes with multiple qPCR were used to determine gene expression in total RNA extracts of cecal cells from rats. The RS vs. EC comparison tested effects of fermentation as energy density of the diet was controlled. RESULTS: For the RS vs. EC comparison, 86% of the genes were validated from the microarray and the expression indicates promotion of cell growth, proliferation, differentiation, and apoptosis. Gut hormones GLP-1 and PYY were increased. CONCLUSIONS: Gene expression results predict improved structure and function of the GI tract and production of gut hormones may promote healthy functions beyond the GI tract