The impact of 1-year vitamin D supplementation on vitamin D status in athletes: a dose–response study

• Published in: European journal of clinical nutrition Vol. 70; no. 9; pp. 1009 - 1014
• Main Authors: Backx, E M P, Tieland, M, Maase, K, Kies, A K, Mensink, M, van Loon, L J C, de Groot, L C P G M
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.09.2016; Nature Publishing Group
• Subjects: 101/58; 631/443/810; 692/53; Adolescent; Adult; Afdeling Humane voeding; Athletes; Blood; Calciferol; Care and treatment; Chair Nutrition and Health over the Lifecourse; Cholecalciferol - blood; Cholecalciferol - pharmacology; Cholecalciferol - therapeutic use; Clinical Nutrition; Dietary intake; Dietary Supplements; Dose-response relationship; Double-Blind Method; Drug therapy; Epidemiology; Female; Global Nutrition; Health aspects; HNE Nutrition and Health over the Lifecourse; HNE Voeding en Gezondheid in de Levenscyclus; Human Nutrition; Human Nutrition & Health; Human Nutrition (HNE); Humane Voeding; Humane Voeding & Gezondheid; Humans; Internal Medicine; Male; Medicine; Medicine & Public Health; Metabolic Diseases; Netherlands; Nutrient deficiency; original-article; Public Health; Sports Medicine; Summer; Sunlight; Vitamin D; Vitamin D - analogs & derivatives; Vitamin D - blood; Vitamin D deficiency; Vitamin D Deficiency - blood; Vitamin D Deficiency - drug therapy; Vitamin D3; Vitamin deficiency; VLAG; Wereldvoeding; Young Adult
• ISSN: 0954-3007; 1476-5640
• DOI: 10.1038/ejcn.2016.133

Background/Objectives: To assess the prevalence of vitamin D deficiency in Dutch athletes and to define the required dosage of vitamin D 3 supplementation to prevent vitamin D deficiency over the course of a year. Subjects/Methods: Blood samples were collected from 128 highly trained athletes to assess total 25(OH)D concentration. Of these 128 athletes, 54 male and 48 female athletes (18–32 years) were included in a randomized, double blind, dose–response study. Athletes with either a deficient (<50 nmol/l) or an insufficient (50–75 nmol/l) 25(OH)D concentration were randomly assigned to take 400, 1100 or 2200 IU vitamin D3 per day orally for 1 year. Athletes who had a total 25(OH)D concentration above 75 nmol/l at baseline continued with the study protocol without receiving vitamin D supplements. Serum total 25(OH)D concentration was assessed every 3 months, as well as dietary vitamin D intake and sunlight exposure. Results: Nearly 70% of all athletes showed an insufficient (50–75 nmol/l) or a deficient (<50 nmol/l) 25(OH)D concentration at baseline. After 12 months, serum 25(OH)D concentration had increased more in the 2200 IU/day group (+50±27 nmol/l) than the sufficient group receiving no supplements (+4±17 nmol/l; P <0.01) and the 1100 IU/day group (+25±23 nmol/l; P <0.05). Supplementation with 2200 IU/day vitamin D resulted in a sufficient 25(OH)D concentration in 80% of the athletes after 12 months. Conclusions: Vitamin D deficiency is highly prevalent in athletes. Athletes with a deficient or an insufficient 25(OH)D concentration can achieve a sufficient 25(OH)D concentration within 3 months by taking 2200 IU/day.