the epidemiology of dietary supplements consumption in the athletes of karaj iran

background and aims: nutrition has a determinant role in success of professional athletes and dietary supplements can play an important role for supplying the nutritional needs for them in some situations. consumption of dietary supplements (ds) was significantly increased in recent years. based on this fact, assessing the amount, purposes and type of the supplements are all as prior as the affective factors on the choice and preparation of that. therefore, we are going to evaluate the consumption of dietary supplement among athletes of karaj, a big city near tehran, capital of iran. methods: in this cross-sectional study, we enrolled 195 athletes that were randomly selected from 8 sport clubs of karaj city between december 2014 and february 2015. a self-administered questionnaire containing 17 questions was used to evaluate the field of sport, history and reasons of consuming the supplements, source of information and providing centers. validity and reliability of questionnaire determined through panel of experts and cronbach’s alpha (n=25, α=0.85) respectively. results: the mean age of the athletes was 24±7 years old. thirty six percent of participants consumed the supplement during the study and 49% reported the previous use of it. the most important reasons of supplement’s consumption were empowering sport’s ability by 48%. also supplying needs of body by 39% and increasing muscle’s mass by 31% named the second and third reason of supplement use. for 64% of participants coach is the most important source of information and question about ds, and then nutritionists (24%) and internet (23%) were after that in order. sixty one percent of participants considered the coach as the most important source for buying supplements and then 51% of participants mentioned pharmacies as second main source for buying ds. protein supplements, vitamins, creatine and glutamine were named as the most commonly used ds. discussions: the results of this study indicate that dietary supplements usage is common among athletes. according to these results, coaches have a significant role in athlete information and supplying the required supplements of athletes. it is necessary to consider the appropriate policy to remove coaches from the supply chain of dietary supplements.