Whey protein isolate counteracts the effects of a high-fat diet on energy intake and hypothalamic and adipose tissue expression of energy balance-related genes

Abstract

The intake of whey protein isolate (WPI) is known to reduce high-fat diet (HFD)-induced body-weight gain and adiposity. However, the molecular mechanisms are not fully understood. To this end, we fed C57BL/6J mice for 8 weeks with diets containing 10 % energy as fat (low-fat diet, LFD) or 45 % energy as fat (HFD) enriched with either 20 % energy as casein (LFD and HFD) or WPI (high-fat WPI). Metabolic parameters and the hypothalamic and epididymal adipose tissue expression of energy balance-related genes were investigated. The HFD increased fat mass and plasma leptin levels and decreased the dark-phase energy intake, meal number, RER, and metabolic (VO 2 and heat) and locomotor activities compared with the LFD. The HFD increased the hypothalamic tissue mRNA expression of the leptin receptor, insulin receptor (INSR) and carnitine palmitoyltransferase 1b (CPT1b). The HFD also reduced the adipose tissue mRNA expression of GLUT4 and INSR. In contrast, WPI reduced fat mass, normalised dark-phase energy intake and increased meal size in HFD-fed mice. The dietary protein did not have an impact on plasma leptin, insulin, glucose or glucagon-like peptide 1 levels, but increased plasma TAG levels in HFD-fed mice. At a cellular level, WPI significantly reduced the HFD-associated increase in the hypothalamic tissue mRNA expression of the leptin receptor, INSR and CPT1b. Also, WPI prevented the HFD-induced reduction in the adipose tissue mRNA expression of INSR and GLUT4. In comparison with casein, the effects of WPI on energy intake and hypothalamic and adipose tissue gene expression may thus represent a state of reduced susceptibility to weight gain on a HFD.

Consumption of a Mango Fruit Powder Protects Mice from High-Fat Induced Insulin Resistance and Hepatic Fat Accumulation

“…In liver we observed an increase in Insr and hepatokine Fgf21 mRNA expression levels (Fig. 3), whereas in WAT, a decrease in mRNA expression levels of Insr compared to control animals was seen (data not shown), as previously reported [45, 46], indicating a dysfunctional adipose tissue, resulting in an increased flux of FFAs to the liver or muscle cells and other organs. In skeletal muscle, we observed some adaptations (i.e.…”

Exercise, fitness, and the gut

“…Unsurprisingly, energy intake was significantly greater amongst athletes across all major food groups, however, considerably more of the daily energy intake for athletes relied on protein, in particular whey protein consumption. Whey protein, known for its postexercise recovery effects and muscle hypertrophy results [87], may contribute to gut microbiota composition and potentially to lipid metabolism [88,89]. This example clearly outlines the close affiliation between the triad of diet, metabolism, and exercise.…”

Whey protein effects on energy balance link the intestinal mechanisms of energy absorption with adiposity and hypothalamic neuropeptide gene expression

“…In each week, different groups were selected, where all the mice in each selected home cage were housed in the Phenomaster cages to collect the data. The data corresponding to food and water intake, substrate metabolism [represented by respiratory exchange ratio (RER)], oxygen consumption (V O2), and locomotor activity (in the x-, y-, and z-axis), were recorded in the final 24 h of the housing period, as detailed previously (24), with the exception that measurements were taken during a 1.5-min time period/cage every 13 min rather than 1 min/cage every 9 min as used previously.…”

“…Gene expression was calculated using 2 -⌬⌬Cp and normalized against the reference gene ␤-actin. The sequences of the primers are detailed elsewhere (24,26,29,33).…”