Vitamin D Status in Division III Male Cross Country and Track Runners

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Few studies have examined serum vitamin D [25(OH) D] in athletes. The lack of measurement is due to the expectation that humans will synthesize adequate amounts of 25(OH) D with UVB sunlight exposure and are not reliant on dietary sources of vitamin D. Recent research challenges this assumption especially during winter months and questions the adequacy of the dietary recommendation or Adequate Intake [AI] for vitamin D (Willis, K., Peterson, N., and Larson-Meyer, E. (2008). PURPOSE: To evaluate vitamin D status [dietary vitamin D intake and serum 25 (OH) D] of male cross-country and track runners. METHODS: Subjects, aged 18 - 22, completed three day diet records twice during the year which were analyzed using diet analysis software. Blood samples were collected at four points during the year, serum was frozen at -80oC, and analyzed for levels of 25(OH) D using an ELISA procedure. Average daily solar radiation [SR ave.] for the month prior to each serum 25(OH) D measurement was obtained from the Midwestern Regional Climate Center database. RESULTS: Mean dietary vitamin D intake was 7 μg/day ± 4 [AI for vitamin D = 5 μg (200 IU)] in September and 8 μg/day ± 6 in February. There is no correlation between dietary vitamin D intake and serum 25 (OH) D, r = 0.16 for September, and 0.04 for February. The correlation of mean values for 25 (OH)D at each time point with SR ave. was r = 0.76.TABLECONCLUSIONS: These results support the need to monitor vitamin D especially during the winter months. Some individuals become deficient despite adequate dietary intake of vitamin D and thus may need to supplement vitamin D or obtain controlled UVB exposure to reduce the consequences of vitamin D deficiency.