Sports Nutrition Knowledge, Dietary Practices, Supplement Beliefs, and Anthropometric Characteristics of Modern Pentathlon Athletes: A Cross-Sectional Study

Modern pentathlons impose high physiological demands on adolescent and young adult athletes, whose nutritional requirements are further increased by growth and maturation. Evidence on sports nutrition knowledge, dietary practices, supplement beliefs, and anthropometric characteristics in adolescent and young adult pentathletes remains limited. This cross-sectional study evaluated these parameters in 50 modern pentathletes aged 10–22 years (22 females, 28 males) training at the Turkish Olympic Preparation Centre. Participants completed the Nutrition for Sport Knowledge Questionnaire (NSKQ), Sport Supplement Belief Scale (SSBS), and a 24-hour dietary recall; anthropometric measurements and nutrient adequacy were also assessed. Poor nutrition knowledge was observed in 98.0% of participants. Meal skipping was reported by 44.0% of athletes. Mean energy adequacy was 72.5 ± 27.65%, carbohydrate intake was below general sports nutrition recommendations (4.07 ± 1.90 g/kg/day), and protein intake met recommendations (1.7 ± 0.73 g/kg/day). Calcium intake reached approximately 50% of recommended levels, while selenium intake in females met 40% of the Recommended Dietary Allowance (RDA) and was significantly lower than in males (p = .021). Most athletes (80.0%) were within the normal Body Mass Index (BMI) range; BMI increased with age, and females had higher body fat percentages than males. Athletes consuming no fluids during training had higher SSBS scores than those consuming sports drinks (p = .035). These findings indicate inadequate sports nutrition knowledge, suboptimal carbohydrate and calcium intake, and inconsistent hydration practices, supporting the need for structured, sport-specific nutrition education and regular monitoring.