You can build muscles with vegetable proteins with a low biological value, such as the wheat protein. But you will have to consume those low-quality proteins in large amounts. Dutch nutrition scientists from the University of Maastricht report about this in the Journal of Nutrition.
The researchers experimented with 5 groups of 12 men aged 65-80 years. They gave the men a portion of protein, and then monitored the manufacture of muscle tissue by analyzing the disappearance of amino acids from the blood.
The type and dose of protein differed per group. The groups received 35 grams of whey, 35 grams of casein, 35 grams of wheat protein, 35 grams of wheat protein hydrolysate and 60 grams of wheat protein hydrolysate.
First of all, the Dutch discovered that the muscle-building effect of wheat protein was just as great as the muscle-building effect of the hydrolyzed wheat protein. That’s weird counterintuitive.
After intake of 35 grams of casein or 35 grams of whey the men built up more muscle than after ingesting 35 grams of hydrolyzed wheat protein. The biological value of casein and gram whey exceeds that of wheat protein, so that is not so strange.
The dose of 60 grams of wheat protein hydrolysate again had a stronger muscle building effect than 35 grams of whey.
“We hypothesized that ingesting a greater dose of wheat protein hydrolysate, matched for the amount of leucine present in 35 g whey protein, would result in a similar postprandial increase in plasma amino acid concentrations and muscle protein synthesis rates as observed after the ingestion of the Whey-35”, the Dutch write.
“Despite an equal leucine content in the WPH-60 and Whey-35 bolus (both 4.4 g leucine), we observed that plasma leucine concentrations increased to a greater extent after the ingestion of the Whey-35 than after WPH-60.”
“The more sustained appearance of amino acids into the circulation after the ingestion of WPH-60 than after Whey-35 resulted in a greater stimulation of postprandial muscle protein synthesis rates. […] A more sustained provision of amino acids may facilitate the delayed postprandial increase in muscle protein synthesis in older individuals, resulting in a greater postprandial muscle protein synthetic response after the ingestion of WPH-60 than after Whey-35.”
“We conclude that the postprandial muscle protein synthetic response to the ingestion of 35 g casein is greater than the response to the ingestion of the same amount of wheat protein”, summarize the researchers. “The ingestion of a larger amount of wheat protein (i.e., 60 g) substantially increases myofibrillar protein synthesis rates in healthy older men.”
“These data provide useful information when developing or optimizing food product formulations combining wheat or other plant-based proteins with dairy proteins to stimulate muscle protein synthesis rates and to support muscle mass maintenance.”
J Nutr. 2016 Sep;146(9):1651-9.