Evaluation of nutritional knowledge and consequences of consuming dietary supplements among expert bodybuilders

Background: of specific education programs from unreliable sources causes low nutrition knowledge and the use of many dietary supplements (DS) in bodybuilders. This study investigated the nutritional knowledge and prevalence of DS among Iranian bodybuilders. Method: This cross-sectional research involved a sample of 648 bodybuilding clubs in Iran and a researcher who distributed questionnaires among clubs in different regions and analyzed categorical variables, DS, nutritional knowledge, and sports nutrition data from 160 bodybuilders aged 18 and above in Iran with the results of a quantitative questionnaire. Results: There was a significant relationship between DS use and gender (p=0.000, r= 0.330), bodybuilding history (p=0.045; r=0.158), participation in nutrition courses (p=0.161, r=0.111), and exercise sessions per week (p=0.050, r=0.156). Whey protein (45.62%) and BCAA (33.75%), vitamin D (50%), Vitamin C (56.25%), caffeine (34.37%), and generally vitamin C (56.25%) were the most common DS used. The most information sources for bodybuilders regarding DS were trainers (35.62%) and nutritionists (34.37%), and regarding nutrition, registered dietitians/nutritionists (58.1%) and trainers (51.87%). Total nutritional knowledge (macronutrients, micronutrients, and sports nutrition) was 58.65%. There was a significant relationship between nutrition knowledge and bodybuilding history (p=0.001, r=0.264) and participation in nutrition courses (P=0.000, r= 0.384). Conclusion: This study concluded that the most common information sources for bodybuilders were coaches and nutritionists and found poor nutrition knowledge among bodybuilders. The most common DS used by bodybuilders were vitamins C, D and Whey protein. Also, gender, bodybuilding history, and the number of weekly exercise sessions had a significant relationship with the prevalence of DS.