No differences in muscle protein synthesis rates following ingestion of wheat protein, milk protein, and their protein blend in healthy, young males

Abstract

Plant-derived proteins have been suggested to have less anabolic properties when compared with animal-derived proteins. Whether blends of plant- and animal-derived proteins can compensate for their lesser anabolic potential has not been assessed. This study compares post-prandial muscle protein synthesis rates following the ingestion of milk protein with wheat protein or a blend of wheat plus milk protein in healthy, young males. In a randomized, double blind, parallel-group design, 36 males (23±3 y) received a primed continuous L-[ring-13C6]-phenylalanine infusion after which they ingested 30 g milk protein (MILK), 30 g wheat protein (WHEAT), or a 30 g blend combining 15 g wheat plus 15 g milk protein (WHEAT+MILK). Blood and muscle biopsies were collected frequently for 5 hours to assess post-prandial plasma amino acid profiles and subsequent myofibrillar protein synthesis rates. Ingestion of protein increased myofibrillar protein synthesis rates in all treatments (P<0.001). Post-prandial myofibrillar protein synthesis rates did not differ between MILK vs WHEAT (0.053±0.013 vs 0.056±0.012 %∙h-1, respectively; t-test P=0.56) or between MILK vs WHEAT+MILK (0.053±0.013 vs 0.059±0.025 %∙h-1, respectively; t-test P=0.46). In conclusion, ingestion of 30 g milk protein, 30 g wheat protein, or a blend of 15 g wheat plus 15 g milk protein increases muscle protein synthesis rates in young males. Furthermore, muscle protein synthesis rates following the ingestion of 30 g milk protein do not differ from rates observed after ingesting 30 g wheat protein or a blend with 15 g milk plus 15 g wheat protein in healthy, young males.

Evaluating the Leucine Trigger Hypothesis to Explain the Post-prandial Regulation of Muscle Protein Synthesis in Young and Older Adults: A Systematic Review

“…Perhaps surprisingly, our findings indicate that the strength of evidence supporting the leucine trigger hypothesis is greater in older vs. young adults. In this regard, only three study arms in young adults provide evidence supporting the leucine trigger hypothesis ( 15 , 33 , 44 ), while seven studies refute the hypothesis ( 19 , 32 , 42 , 43 , 45 – 47 ). In contrast, the preponderance of evidence in older adults supports the leucine trigger hypothesis, with 13 studies reporting a greater post-prandial leucinemia following protein ingestion to correspond with an increased stimulation of MPS, and only seven studies reported a disconnect between the blood leucine concentration profile and post-prandial rates of MPS.…”

The Anabolic Response to Plant-Based Protein Ingestion

“…Only a handful of studies have directly compared postprandial muscle protein synthesis rates following ingestion of plant-versus animal-derived proteins [13,14,16,[36][37][38]. Ingestion of soy protein has been shown to be less effective in stimulating post-prandial muscle protein synthesis rates when compared with the ingestion of an equivalent amount of whey protein in both young and older adults at rest and during recovery from exercise [13,14,36], but more effective than casein protein [13].…”

“…Not surprisingly, this also raises questions regarding the impact of the (lower) quality of plant-based proteins on muscle conditioning during recovery from exercise. There are only a handful studies that have compared post-exercise muscle protein synthetic responses following the ingestion of plant-versus animalderived proteins [13,14,16,[36][37][38]. In these studies, the main plant-derived protein that has been applied is soy protein.…”

“…This includes an increase in the consumption of plant-based proteins at the expense of animal-based proteins. Although the current market already offers a wide selection of plantderived proteins and plant-based protein sources, there is a paucity of studies that have assessed the bio-availability and anabolic properties of plant-based proteins [13,14,16,[36][37][38]. Some [14,16,36], but not all [13,37,38] of these studies show that the ingestion of plant-derived proteins, such as soy and wheat protein, results in a lower muscle protein synthetic response when compared with the ingestion of an equivalent amount of animal-derived protein.…”

“…Although the amino acid composition can be quite variable between different plant-based proteins, most plant-based proteins are relatively low in essential amino acid content and are often deficient in one or more specific amino acid, such as leucine, lysine, and/or methionine [39]. So far, only a few studies have directly compared the muscle protein synthetic response following the ingestion of a plant-derived protein versus a high(er) quality animal-derived protein [13,14,16,[36][37][38]. Furthermore, even less is known about the different strategies that can be applied to improve the anabolic properties of plant-based proteins.…”