|Dairy or eggs? Why not just dairy and eggs - Protein mix exerts most promising effects on signalling proteins related to increased muscle mass and fat loss, analysis of the results of a study shows.|
Well, despite the fact that this is a rodent study and irrespective of the questionable link between acute markers of protein synthesis and long-term gains, this is imho the first study to compare the effects whey and egg proteins have on skeletal muscle, adipose tissue and hypothalamic satiety-related markers at the same time.
To do so, Mobley et al. gave their lab rats (a) whey protein concentrate (WPC, n = 15), (b) hydrolyzed whey-to-hydrolyzed egg albumin at a ratio of 70:30 (70 W/30E, n = 15), the same mix at a ratio of (c) 50/50 and (d) 30/70 or (e) 1 ml of water with no protein as a fasting control.
|Figure 1: Expression of protein synthesis and selected signalling proteins in skeletal muscle (PGC-1a, AMPK) and brain (POMC) in response to the different protein supplements (Mobley, 2015).|
- WPC and 70 W/30E increased muscle protein synthesis (MPS) 104% and 74% 180 min post-treatment, respectively (p < 0.05), and
- 70 W/30E increased p-AMPKα (Thr172) 90 and 180-min post-treatment as well as PGC-1α mRNA 90 min post-treatment.
A closer analysis of the protein responses in the subcutaneous (SQ) and omental fat (OMAT) depots of the rodents showed that
- 70 W/30 W increased SQ fat phosphorylated hormone-sensitive lipase [p-HSL (Ser563)] 3.1-fold versus CTL and a 1.9–4.4-fold change versus all other test proteins 180 min post-treatment (p < 0.05); and
- WPC, 70 W/30E and 50 W/50E increased OMAT p-HSL 3.8–6.5-fold 180 min post-treatment versus CTL (p < 0.05).
Lastly, the 70 W/30E and 30 W/70E increased hypothalamic POMC mRNA 90 min post-treatment versus CTL, an effect that suggests that an increased satiety response may have occurred in the former groups. An effect that was not counter by a compensatory increase in orexigenic (=appetite increasing) AGRP mRNA in the 70 W/30E group 90 min post-treatment versus and compensated by increases in orexigenic NPY mRNA in the 30 W/70E group 90 min post-treatment.
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- Mitchell, Cameron J., et al. "Last Word on Viewpoint: What is the relationship between the acute muscle protein synthetic response and changes in muscle mass?." Journal of Applied Physiology 118.4 (2015): 503-503.
- Mobley, Christopher Brooks, et al. "Effects of protein type and composition on postprandial markers of skeletal muscle anabolism, adipose tissue lipolysis, and hypothalamic gene expression." Journal of the International Society of Sports Nutrition 12.1 (2015): 14.
- Norton, Layne E., et al. "Leucine content of dietary proteins is a determinant of postprandial skeletal muscle protein synthesis in adult rats." Cellulose (Fiber) 53.53.7 (2012): 53-7.