Protein shakes can help you maintain or improve your muscle mass mass.
But which type should you choose?
Canadian researchers studied three types of protein and compared their muscle building effects.
Proteins are the building blocks of muscle tissue, and ingestion of protein signals the body that there is plenty of these building blocks available to start building muscle.
It has been well established that increasing the amount of daily protein consumption can help maintain muscle mass in the elderly or during dieting. Furthermore, protein ingestion can improve the muscle building effects seen after exercise.
But which type of protein is the most effective to maintain or improve muscle mass?
Protein can be devided in two types: slow and fast. Proteins consist of amino acids, into which protein is digested after consumption.
Amino acids from slow digesting proteins appear in the blood more slowly, have a lower peak value, and have a longer lasting effect when compared to fast digesting proteins.
Casein is an example of a slow protein, whereas whey and soy protein are fast.
Hydrolysates are proteins that are prepared using a treatment method that pre-digests protein into smaller fractions, which could make a protein faster.
The figure below shows how much amino acids the researchers measured in the blood at various times after the consumption of the different protein shakes.
As they expected, the amino acid peak from whey protein was the hightest, followed by soy protein and then finally micellar casein.
The protein fractional synthetic rate, a marker for muscle growth, was also measured. Interestingly, it showed a pattern that corrisponded to amino acid peak from the proteins: whey hydrolysate > soy protein > micellar casein.
Thus, the researchers speculated that the speed of a protein is an important factor in its ability to stimulate muscle growth.
However, the digestion speed is not the only difference between the proteins. Each protein has a unique amino acid composition.
Previous research has indicated that leucine is the key amino acid that turns the muscle building switch. Whey protein has a higher percentage of leucine compared to the other proteins.
Therefore, the authors theorize that the amino acid composition is an important determinent as well, and the effectiveness of protein may depend on its ability to produce a quick and large peak in blood leucine values.
So if you choose a protein supplement to improve your body composition, whey hydrolysate appears to be a good choice compared to soy protein or micellar casein. If you want to estimate the effectiveness of protein supplements, you can check the label for its leucine content and compare.