Sports nutrition products are used by individuals of all athletic levels to improve performance in sports and help maintain overall health. Sports nutrition has expanded from athlete-focused nutrition to include a wide variety of product categories, such as nutritional supplements, beverages and bars. Soy protein is a critical ingredient in sports nutrition products because it is a widely available, complete, high-quality protein.
Protein helps muscles grow and recover during exercise. Muscle gain occurs when growth, or skeletal muscle protein synthesis (SMPS), exceeds loss, or skeletal muscle protein breakdown (SMPB)1
. When combined with proper nutrition, resistance exercise, such as weight lifting, can lead to muscle gain over time1
. Amino acids, the building blocks of protein, stimulate muscle synthesis in the period following a workout, driving additional muscle gain2
. Two specific amino acids, glutamine and arginine, help regulate muscle protein balance6
. Soy protein contains more glutamine and arginine than whey protein or casein. Arginine, as well as the branched chain amino acids leucine, valine and isoleucine, may help with muscle recovery. The branched chain amino acids are utilized during endurance exercise to provide energy to working muscles8
Soy protein isolate, whey protein and casein are three proteins widely used in sports nutrition. Their differing digestion rates and amino acid ratios give them unique functionality for inclusion in sports nutrition products11
. Consuming a combination of proteins with different digestion rates may enhance lean body mass gains by promoting longer periods of muscle growth after exercise15
. Any combination of soy protein isolate, casein and whey protein will be a nutritionally “complete protein,” because each has a PDCAAS (Protein Digestibility Corrected Amino Acid Score) of 1.00. The optimal formulation for a blend of soy protein isolate, casein and whey protein both jump-starts muscle development and maintains nutrient delivery to muscles during and post-exercise.
Athletes of all levels should read packages and labels carefully to determine which type(s) of protein each sport nutrition product includes and strive for a combination of soy protein isolate, whey protein and casein. It is important to consider protein and calories from sports nutrition products as part of total dietary intake to maintain a healthy body weight. Lastly, many myths exist about the impact of increased soy protein intake and may stop athletes from including soy protein in their diet. Knowing the truth about soy protein is important for making the right sports nutrition choices. View all sources cited
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