Protein quality: It’s not all about quantity
Protein is important for athletes due to the physical demands of training on muscles – higher protein intake is required for athletes to support repairing and rebuilding muscle tissue for performance.
But does the quality of our protein matter? More specifically, is the quality different whether it comes from an animal or plant? Again, this is not a black and white answer but cooking strategies can improve the quality of plant-based proteins.
Let’s first look at the fundamental basics of protein – amino acids are the building blocks of proteins in our food and body and they play a vital role in muscle health for athletes. In our food, there are 20 amino acids, and nine of these are considered essential, meaning our body doesn’t have the ability to make them.
Animal-based proteins are considered high-quality, or complete proteins, because they contain all nine essential amino acids. Whereas plant-based proteins are low-quality, or incomplete, because they are missing one or more essential amino acids. Plant-based proteins can become a moderate quality by combining complementary proteins, such as rice and beans – by combining the rice and beans, the amino acid profile is now complete.
Most important for our athletes is the consideration for the amino acids which play a significant role in fuelling muscles and recovery. Three essential amino acids are branch-chain amino acids (BCAAs): leucine, isoleucine, and valine, which are more concentrated in animal-based protein compared to plant protein.
BCAAs are particularly important for promoting muscle protein synthesis (MPS) – think muscle gains. These BCAAs are rapidly digested and considered ‘fast’ proteins. Fast proteins supply amino acids quickly after ingestion to stimulate muscle repair and begin building new muscle. Whey, a popular protein shake, is high in BCAAs and is a fast protein. Whey is filtered from cow’s milk, meaning it is a high-quality protein. Soy is also considered a fast protein but does not stimulate the pathways to build muscle in the same way as whey. Soy is lower in leucine, an essential amino acid driving the anabolic response (building new muscle).
Animal-based foods, such as eggs, chicken, and milk have a higher concentration of BCAAs compared to plant-based sources like peas and soy. Following a vegan diet reduces the amount of BCAAs which help support muscle synthesis.
One last note about the differences between amino acids from animal and plant-based sources is the digestibility. Plant proteins contain other properties that reduce our bodies’ ability to absorb the amino acids completely. However, during the cooking phase of plant proteins, the digestibility can be improved. Soaking, fermentation, and germination can reduce the level of properties reducing protein absorption. Even with the differences, vegetarians and vegans can meet their protein and amino acid daily needs.