Vitamin D3 Supplementation Reduces the Symptoms of Upper Respiratory Tract Infection during Winter Training in Vitamin D-Insufficient Taekwondo Athletes: A Randomized Controlled Trial

Abstract

Vitamin D insufficiency may be associated with increased risk of upper respiratory tract infection (URTI) in athletes. This study examined the effects of vitamin D3 supplementation on salivary immune functions and symptoms of URTI in vitamin D-insufficient taekwondo athletes. Twenty-five male taekwondo athletes, aged 19–22 years with vitamin D insufficiency [serum 25-hydroxyvitamin-D concentrations (25(OH)D, 31.3 ± 1.39 nmol/L)], participated in this study. They were randomized to receive 5000 IU/day of vitamin D3 (n = 13) or placebo capsule (n = 12) during 4 weeks of winter training. Blood samples were collected two times (pre- and post-tests) for analyzing serum 25(OH)D concentration while salivary samples were obtained three times (pre-, mid-, and post-tests) for secretory immunoglobulin A (SIgA) and lactoferrin analyses. The symptoms of URTI were reported daily during the intervention. Serum 25(OH)D concentration significantly increased by 255.6% in the vitamin D group, whereas in the placebo group it did not change (p < 0.001). While the significant increase in SIgA was observed in both groups (p < 0.001), elevated salivary lactoferrin level in response to winter training was found only in the placebo group (p = 0.011). The change in serum 25(OH)D concentration was negatively associated with total URTI symptoms (r = −0.435, p = 0.015). Vitamin D3 supplementation may be effective in reducing the symptoms of URTI during winter training in vitamin D-insufficient taekwondo athletes.

Vitamin D and upper respiratory tract infections in young active males exposed to cold environments

“…It is possible that the lack of variation in 25(OH)D concentration between groups may have reduced the ability to detect a relationship between vitamin D and URTI episodes, which is consistent with the findings reported by Scullion et al [39]. It should be noted that the reduction in URTI risk achieved via vitamin D supplementation appears to be greater in cohorts with severe vitamin D deficiency [17,40,41], which may also explain the lack of association between 25(OH)D concentration and URTI in the current study.…”

The Role of Vitamin D in Combination Treatment for Patients With Rheumatoid Arthritis

“…A prior study suggested that the overall infection rate increased significantly during RA onset, and the antibacterial defense mechanism was defective (33). Recently, authors reported that VitD supplementation effectively reduced the incidence of acute cellular rejection and infection (34,35), upper respiratory infection (36,37) and acute respiratory infections (36,38). However, we obtained different results compared with the above studies.…”

Vitamin D Update

“…That vitamin D should play a role in COVID-19 is not unexpected, since there has been believed to be a link between vitamin D deficiency and respiratory disease for over 100 years. Observational studies have reported independent associations between low serum concentration of 25hydroxyvitamin D and susceptibility to acute respiratory tract infections [40]. Vitamin D deficiency is associated with an increased risk of the acute respiratory distress syndrome (ARDS), intensive care admission, and mortality in patients with pneumonia [41].…”