Key Question Investigated While acknowledging the general concerns that many have about the antioxidant status of the general population, I have focused on the relevance of dietary antioxidants in athletes. The two broad themes of the thesis are: the effect of usual dietary intake on antioxidant status in athletes, and the impact of dietary antioxidants on athletic performance. The overall aim of this thesis was threefold: 1) To determine the antioxidant intake of athletes 2) To investigate the impact dietary antioxidant intake has on antioxidant status 3) To assess the impact of dietary antioxidants on training and performance Structure This thesis comprises seven chapters (Table 1), beginning with this introduction and ending with an overall conclusion. The thesis comprises 7 chapters separated into in 2 thematic sections, each introduced with a literature review (Table 1) and followed with 1-2 experimental studies. Table 1: Overview of doctoral thesis chapter flow Chapter 1: Introduction and Rationalisation (Preface) Thematic section: dietary intake and antioxidant status in athletes Chapter 2: Literature Review: Dietary intake, metabolism and action of vitamin C and other dietary antioxidants in active individuals Chapter 3: Development and validation of a food frequency questionnaire to assess short term antioxidant intake in athletes Chapter 4: Effect of dietary antioxidants and exercise on antioxidant status in elite rowers Thematic section: dietary antioxidants and athletic performance Chapter 5: Literature Review: Impact of Dietary Antioxidants on Sport Performance Chapter 6: Effects of dietary antioxidants on training and performance in female runners Chapter 7: Conclusion Appendices