25(OH)D levels in trained versus sedentary university students at 64° north

Abstract

Purpose: 25-hydroxyvitamin D (25[OH]D) deficiency is associated with compromised bone mineralisation, fatigue, suppressed immune function and unsatisfactory skeletal muscle recovery. We investigated the risk of 25(OH)D insufficiency or deficiency in endurance athletes compared to sedentary non-athletes living at 64° north.Methods: University student-athletes (TS) and sedentary students (SS) volunteered to participate in this study. TS engaged in regular exercise while SS exercised no more than 20 minutes/week. Metabolic Equivalent of Task (MET) scores for participants were determined. Vitamin D intake was assessed using the National Cancer Institute’s 24-hour food recall (ASA24). Fasting plasma 25(OH)D levels were quantified via enzyme-linked immunosorbent assay.Results: TS reported higher activity levels than SS as assessed with MET-minutes/week and ranking of physical activity levels (p < 0.05). The reported mean daily intake of vitamin D was higher in TS compared to SS (p < 0.05) while 25(OH)D plasma levels were lower in TS than in SS (p < 0.05). In total, 43.8% of the TS were either insufficient (31.3%) or deficient (12.5%) in 25(OH)D, while none of the SS were insufficient and 13.3% were deficient.Conclusion: TS are at increased risk of 25(OH)D insufficiency or deficiency compared to their sedentary counterparts residing at the same latitude, despite higher vitamin D intake.

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

“…Our results show that vitamin D insufficiency (<50nmol/L) was not associated with a lowered CMJ height in spring and summer, following adjustments for co-variates. This contrasts to previous literature regarding predictors of lower body muscular strength [ 32 , 33 ] and countermovement jump [ 31 , 32 ]. This could be attributed to our athletes having a lower baseline CMJ height 35.7 ± 6.8 when contrasted against the preliminary results from other cross-sectional studies: UK club-level athletes (47.0 ± 6.9cm [ 32 ]), south Korean collegiate athletes (54.1 ± 1.03cm [ 34 ]), polish ice-hockey players (42.4 ± 4.8cm [ 29 ]) and US collegiate athletes (47.21 ± 1.7cm [ 33 ]).…”

“…A limitation of our investigation is that sunlight exposure practices were not explored with a validated questionnaire, unlike other vitamin D studies [ 31 ]. Nonetheless we did measure direct sunlight exposure across the seasons with dosimetry.…”

Prevalence and Treatment of Vitamin D Deficiency in Young Male Russian Soccer Players in Winter

“…Vitamin D deficiency is very common among professional athletes, where it reaches 60% to 80%. Such a deficiency may negatively impact their performance and increase injury rate [23,24,25,26,27]. An insufficient concentration of 25(OH)D is often found among recreational athletes, reaching 76% in this group [28].…”

Exercise Increases Glucose Transporter-4 Levels on Peripheral Blood Mononuclear Cells

“…An important unanticipated finding was higher GLUT4 levels in females compared to males (Figure 3), when both combining student athletes with sedentary students and within the sedentary group. Interestingly, female participants in this study also exhibited significantly higher plasma 25-OH vitamin D levels than their male counter parts, despite male participants reporting higher dietary and supplemental vitamin D intake (38). It was hypothesized that body fat percent may have contributed to this finding given that vitamin D is fat soluble and is stored, in part, in adipose tissue.…”