The relationship between vitamin D status, intake and exercise performance in UK University-level athletes and healthy inactive controls

Abstract

The potential ergogenic effects of vitamin D (vitD) in high performing athletes has received considerable attention in the literature and media. However, little is known about non-supplemented university athletes and students residing at a higher latitude. This study aimed to investigate the effects of vitD (biochemical status and dietary intake) on exercise performance in UK university athletes and sedentary students. A total of 34 athletes and 16 sedentary controls were studied during the spring and summer months. Serum vitD status and sunlight exposure were assessed using LC-MS/MS and dosimetry, respectively. Muscular strength of the upper and lower body was assessed using handgrip and knee extensor dynamometry (KE). Countermovement jump (CMJ) and aerobic fitness were measured using an Optojump and VO2max test, respectively. Statistical analysis was performed using paired/ independent t-tests, ANCOVA and Pearson/ Spearman correlations, depending on normality. VitD status increased significantly over the seasons, with athletes measuring higher status both in spring (51.7±20.5 vs. 37.2±18.9 nmol/L, p = 0.03) and summer (66.7±15.8 vs 55.6±18.8 nmol/L, p = 0.04) when compared to controls, respectively. Notably, 22% of the subjects recruited were vitD deficient during the spring term only (<25nmol/L, n 9). Subjects with ‘insufficient’ vitD status (<50nmol/L) elicited significantly lower CMJ when contrasted to the vitD ‘sufficient’ (>50nmol/l) group (p = 0.055) and a lower VO2 max (p = 0.05) in the spring and summer term (p = 0.05 and p = 0.01, respectively). However, an ANCOVA test showed no significant difference detected for either CMJ or VO2max following adjustments for co-variates. In conclusion, we provide novel information on the vitD status, dietary intake, physical fitness and sunlight exposure of UK young adults across two separate seasons, for which there is limited data at present.

Comparing the Metabolic Profiles Associated with Fitness Status between Insulin-Sensitive and Insulin-Resistant Non-Obese Individuals

“…Another metabolite that increased in IRA was the 1,25-dihydroxyvitamin D. Previous studies have shown that serum 1,25-dihydroxyvitamin D levels increase with exercise [69]. Our data showed lower levels of vitamin D in IRS than ISS, which may explain the higher response to exercise in the IRA group, perhaps due to a greater exposure to sunlight [70].…”

Relationship Between Metabolites of Vitamin D, Free 25-(OH)D, and Physical Performance in Indoor and Outdoor Athletes

“…More recently, the relationships between total 25-(OH)D concentration and performance-related factors in athletes have been observed in many studies (Seo et al, 2019;Kim et al, 2020;Most et al, 2021;Wilson-Barnes et al, 2021). Although the importance of vitamin D for athletes in regard to health and performance was emphasized, the studies found inconsistent results.…”

Vitamin D: The Challenge of Bridging the Gap and the Rationale for Supplementation

“…Poor muscle function increases the risk of falls and low vitamin D status has been linked with poor gait and balance in older people [45] as well as falls [46]. Vitamin D deficiency is also associated and with poor sports/athletic function [47,48].…”