IN THE LAST DECADE sports scientists have made great strides in understanding how muscles work during exercise, how muscles recover, and the primary causes of fatigue. A result of this research has been the development of nutritional formulas that are far more effective in improving muscle performance. Protein is an excellent example. At one time carbohydrate was considered the only macronutrient essential for improving exercise performance. Research conducted at leading universities in the ‘90s clearly demonstrated that protein could improve endurance, reduce muscle damage, and even enhance rehydration.
Most of this research was conducted with whey protein. Whey protein has many advantages for use during aerobic exercise. It is rapidly absorbed, fast-acting, and contains a high percentage of the specific amino acids known to improve exercise performance. If I could choose only one protein to use in sports recovery and energy products it would be whey. However, as we learn more about the metabolic processes that affect endurance and recovery we now understand that it is possible to get an enhanced effect using a combination of proteins.
Each protein has a unique amino acid profile. In other words, each protein is rich in certain amino acids and deficient in others. The key amino acids involved in sports performance include branched-chain amino acids (BCAAs), leucine, isoleucine, valine, arginine and glutamine. Neither whey protein nor soy protein is equally rich in all of these amino acids, but the amino acid profiles of the two proteins is complementary, so that when they are combined they create a better sports protein.
BCAAs can be readily utilized as an energy source during exercise. During extended exercise, almost 20% of a muscle’s energy comes from protein, primarily BCAAs. When a sports drink containing protein is consumed during exercise, the muscles use this protein instead of breaking down muscle protein for energy. This is one reason why a protein-enhanced sports drink reduces muscle damage and speeds muscle recovery.
Of the BCAAs, leucine plays a critical role in turning on both protein and glycogen synthesis, which is why it is such a key player in the recovery process. Recent research shows that valine prevents the release of fatigue signals from the brain, which play a much bigger role in the onset of fatigue than was previously known.
Two other amino acids, arginine and glutamine, have roles in improving muscle performance. Argnine serves as a precursor to the formation of a compound that increases nutrient and oxygen delivery to muscle cells and glutamine is the primary amino acid found in muscles. During intense exercise, muscle glutamine levels are depleted.
The ideal protein would have high levels of all of these key amino acids. As a single protein, whey comes closest to filling the bill. However, by combining proteins we can raise the levels of these key amino acids in a subtle but important way. For example, soy protein has higher levels of arginine, valine and glutamine than whey protein. Thus the addition of soy protein to a predominantly whey formulation enhances the overall effectiveness of the protein component by increasing nutrient delivery to muscle cells, preventing glutamine depletion, and inhibiting the release of brain fatigue signals.
When it comes to protein in sports energy and recovery product, two are definitely better than one.