Paradoxical Relationships between Serum 25(OH)D and Ferritin with Body Composition and Burnout: Variation by Sex and Sports Team

Adequate serum vitamin D and iron levels are thought to influence physical training adaptations and mood positively. The primary purpose of this prospective, observational study was to investigate relationships between serum 25-OH vitamin D/25(OH)D and serum ferritin levels with body composition and...

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Bibliographic Details
Main Authors: Tamara Hew-Butler, Carrie Aprik, Brigid Byrd, Kristin Landis-Piwowar, Valerie Smith-Hale, Matthew VanSumeren, Jordan Sabourin, Gregory Byrd, Jeffrey Martin
Format: Article
Language:English
Published: MDPI AG 2021-09-01
Series:Endocrines
Subjects:
Online Access:https://www.mdpi.com/2673-396X/2/3/30
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Summary:Adequate serum vitamin D and iron levels are thought to influence physical training adaptations and mood positively. The primary purpose of this prospective, observational study was to investigate relationships between serum 25-OH vitamin D/25(OH)D and serum ferritin levels with body composition and athlete burnout symptoms. Seventy-three collegiate athletes (female: <i>n</i> = 49; male: <i>n</i> = 24) from indoor (swimming, basketball) and outdoor (soccer, cross-country) sports were tested pre-season and post-season for serum 25(OH)D and serum ferritin (nutrient biomarkers) via venipuncture; body composition (total lean mass, bone mineral density/BMD, and % body fat) via dual energy X-ray absorptiometry (DXA) scans; and athlete burnout symptoms (post-season) via the athlete burnout questionnaire (ABQ). When male and female cohorts were combined, significant correlations (Pearson’s r) were noted between pre-season serum 25(OH)D versus the change (∆: post-season minus pre-season) in both BMD (r = −0.34; <i>p</i> = 0.0003) and % body fat (r = −0.28; <i>p</i> = 0.015). Serum ferritin ∆ was significantly associated with lean mass ∆ (r = −0.34; <i>p</i> = 0.003). For burnout symptoms, serum 25(OH)D ∆ significantly explained 20.6% of the variance for devaluation of the sport in the male cohort only. Across time, serum 25(OH)D levels decreased while serum ferritin levels increased, non-significantly, in both males and females. Relationships between nutrient biomarkers and body composition were opposite of physiological expectations.
ISSN:2673-396X