Abstract
Background: Whey protein has been shown to be one of the best proteins to stimulate muscle protein synthesis rate (MPS), but other high quality proteins, e.g., animal/porcine-derived, could have similar effects. Objective: To investigate the effects of hydrolyzed porcine proteins from blood (HPB) and muscle (HPM), in comparison to hydrolyzed whey protein (HW), on MPS after intake of 15 g alone or 30 g protein as part of a mixed meal. We hypothesized that the postprandial MPS would be similar for porcine proteins and whey protein. Design: Eighteen men (mean ± SD age: 24 ± 1 year; BMI: 21.7 ± 0.4 kg/m2) participated in the randomized, double-blind, three-way cross-over study. Subjects consumed the three test products (HPB, HPM and HW) in a random order in two servings at each test day. Serving 1 consisted of a drink with 15 g protein and serving 2 of a drink with 30 g protein together with a mixed meal. A flood-primed continuous infusion of (ring-13C6) phenylalanine was performed and muscle biopsies, blood and urine samples were collected for determination of MPS, muscle free leucine, plasma amino acid concentrations and urea excretion. Results: There were no statistical differences between the MPS measured after consuming 15 g protein alone or 30 g with a mixed meal (p = 0.53) of HPB (0.048 ± 0.007 vs. 0.049 ± 0.008%/h, resp.), HPM (0.063 ± 0.011 vs. 0.062 ± 0.011 %/h, resp.) and HW (0.058 ± 0.007 vs. 0.071 ± 0.013%/h, resp.). However, the impact of protein type on MPS reached statistical tendency (HPB vs. HPM (p = 0.093) and HPB vs. HW (p = 0.067)) with no difference between HPM and HW (p = 0.88). Plasma leucine, branched-chain, essential and total amino acids were generally higher for HPB and HW than HPM (p < 0.01), which reflected their content in the proteins. Muscle-free leucine was higher for HPB than HW and HPM (p < 0.05). Conclusion: Hydrolyzed porcine proteins from blood and muscle resulted in an MPS similar to that of HW, although with a trend for porcine blood proteins to be inferior to muscle proteins and whey. Consequently, these porcine-derived muscle proteins can be used similarly to whey protein to support maintenance of skeletal muscle as part of supplements and ingredients in foods.
Highlights
Provision of essential amino acids (EAA) through intake of dietary protein is a necessary composite of an adequate daily energy intake to support overall de novo protein synthesis, both in the context of this paper and for the general maintenance of muscle mass [1,2]
The primary finding in the present study is that hydrolyzed porcine proteins from blood and muscle result in an muscle protein synthesis rate (MPS) not significantly different from hydrolyzed whey protein when consumed in a moderate dose alone (15 g) and in a dose of 30 g as part of a mixed meal
We are not aware of any similar findings, the results suggest that intracellular utilization, for protein synthesis and/or metabolism/oxidation is diminished after intake of hydrolyzed porcine blood protein compared to muscle protein and whey
Summary
Provision of essential amino acids (EAA) through intake of dietary protein is a necessary composite of an adequate daily energy intake to support overall de novo protein synthesis, both in the context of this paper and for the general maintenance of muscle mass [1,2]. The peripheral availability of EAA, often reflected by the postprandial elevation of circulating amino acid, is dependent on (i) the quantity of ingested protein [3], and (ii) the relative content of the EAA in the protein and even specific amino acids [4], as well as (iii) the digestibility and absorption rate of the protein [5,6], with the latter two being components for evaluating the quality of a protein source [7] Both protein amount and energy content are decisive for the overall net protein balance in response to a meal [8]. Whey protein has been shown to be one of the best proteins to stimulate muscle protein synthesis rate (MPS), but other high quality proteins, e.g., animal/porcine-derived, could have similar effects. Serving 1 consisted of a drink with 15 g protein and serving
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