Whey Protein Supplements Show Mixed Results for Teen Soccer Players, Study Finds
A new randomized controlled trial examining the effects of whey protein supplementation on adolescent soccer players has shed light on a surprisingly understudied area of sports nutrition research — the impact of protein supplements on teenage athletes.
The study, authored by Grace A. Zimmerman and colleagues and published in PubMed, tracked 22 adolescent soccer players over a 10-week competitive soccer season, making it one of the few controlled trials to specifically investigate protein supplementation in a young athletic population.
Participants, who were approximately 15.6 years old on average and nearly 60% female, were randomly assigned to consume either 20 grams of whey protein (PRO group, n=10) or a placebo, allowing researchers to isolate the effects of the supplement against the backdrop of regular competitive training.
Why Adolescents Are Different
While protein supplementation is a widely adopted strategy among adult athletes and has been studied extensively in that population, far less research has explored how such supplements affect younger, still-developing athletes. Adolescent athletes face unique physiological considerations, including ongoing growth and development, which may alter how their bodies respond to additional dietary protein.
The researchers assessed two primary outcomes: athletic performance and body composition — both critical factors for competitive soccer players at any level.
Study Design and Population
The trial's randomized controlled design lends credibility to its findings, as participants were assigned to groups in a way intended to minimize bias. With an average BMI percentile of approximately 55.9%, the participants represented a relatively typical range of body sizes for active teenagers, rather than elite or outlier athletes.
The 10-week window aligned with a real competitive soccer season, grounding the research in practical, real-world conditions rather than a laboratory-only setting.
Implications for Youth Sports Nutrition
Protein supplements are widely marketed to young athletes, and many adolescents consume them with the belief that they will enhance muscle growth and sports performance. However, experts have long cautioned that the evidence base for these products in teenage populations remains thin.
This study represents an important step toward filling that gap, offering controlled data on whether whey protein supplementation meaningfully moves the needle on performance metrics and body composition during a competitive season for adolescent soccer players.
Full results and conclusions from the trial are available via the study's PubMed listing.