Dietary supplement use and knowledge among athletes: prevalence, compliance with AIS classification, and awareness of certification programs.

Background: The use of dietary supplements is widespread among athletes, with intake influenced by factors such as sport-discipline, competitive level, and gender. The Australian Institute of Sport (AIS) has categorized supplements based on scientific evidence regarding their efficacy and safety. Despite extensive global research on dietary supplement use among athletes, data on Polish athletes remain limited. Therefore, this study aimed to evaluate supplement use among Polish athletes, considering their competitive level and gender. Additionally, it assessed whether athletes select supplements in accordance with the AIS classification and examined their awareness of supplement certification programs.

Methods: This cross-sectional study included 659 Polish athletes (309 women, 350 men) from various sports, representing both professional (57.7%) and nonprofessional (42.3%) levels. An online questionnaire was used to assess dietary supplement consumption, sources of information regarding supplementation, and knowledge of anti-doping and supplement certification programs. Supplement use was categorized according to the AIS classification (Groups A - D). Statistical analyses, including chi-square tests and Mann - Whitney U tests, were conducted to evaluate differences between professional and nonprofessional athletes, as well as between male and female participants.

Results: A high prevalence of dietary supplement use (91.1%) was observed among Polish athletes, with no significant differences between professional (95.8%) and nonprofessional (94.3%) athletes or between men (92.0%) and women (90.0%). The most frequently consumed supplements were sports drinks (63.9%), electrolyte supplements (51.6%), and isolated protein supplements (54.6%), vitamin D (71.6%), vitamin C (59.8%), with significantly higher intake among professional athletes. Male athletes were more likely than females to consume caffeine (p < 0.001), creatine (p < 0.001), and β-alanine (p < 0.001). Melatonin use was significantly higher among professionals (p < 0.05). Awareness of WADA regulations was moderate (72.7%), but knowledge of supplement certification programs was low, with only 18.2% of professional athletes familiar with Informed Sport, and 10.7% with the Cologne List. Social media was the most common source of supplement information (41.9%), while only 17.6% of athletes consulted qualified specialists in sports nutrition and supplementation area.

Conclusions: This study highlights the widespread use of dietary supplements among Polish athletes, irrespective of competitive level or gender. While many athletes select supplements from AIS Group A, their knowledge of AIS classification and supplement certification programs remains limited. The high reliance on social media for supplement information, combined with the lack of professional guidance, underscores the need for improved education on safe and effective supplementation practices. Given the risks associated with supplement contamination, targeted initiatives should enhance athletes' awareness of anti-doping regulations and certified supplement options.