Should we be concerned about the vitamin D status of athletes?
A surprisingly high prevalence of vitamin D insufficiency and deficiency has recently been reported worldwide. Although very little is known about vitamin D status among athletes, a few studies suggest that poor vitamin D status is also a problem in athletic populations. It is well recognized that vitamin D is necessary for optimal bone health, but emerging evidence is finding that vitamin D deficiency increases the risk of autoimmune diseases and nonskeletal chronic diseases and can also have a profound effect on human immunity, inflammation, and muscle function (in the elderly). Thus, it is likely that compromised vitamin D status can affect an athlete's overall health and ability to train (i.e., by affecting bone health, innate immunity, and exercise-related immunity and inflammation). Although further research in this area is needed, it is important that sports nutritionists assess vitamin D (as well as calcium) intake and make appropriate recommendations that will help athletes achieve adequate vitamin D status: serum 25(OH)D of at least 75 or 80 nmol/L. These recommendations can include regular safe sun exposure (twice a week between the hours of 10 a.m. and 3 p.m. on the arms and legs for 5-30 min, depending on season, latitude, and skin pigmentation) or dietary supplementation with 1,000-2,000 IU vitamin D3 per day. Although this is significantly higher than what is currently considered the adequate intake, recent research demonstrates these levels to be safe and possibly necessary to maintain adequate 25(OH)D concentrations.
Available from: Zafar Iqbal Butt
- "Deficiency of Vitamin D has been associated to enlarged danger of viral diseases, together with HIV and influenza . Hazard of tuberculosis may appear with low ranks of vitamin D : and historically vitamin D was used as a curative substance . Deficiency of vitamin D is described as less than 50 nmol/L or 20 ng/mL, and its insufficient level lies in between 20 -32 ng/mL or 50 -80 nmol/L whereas optimum level is more than 40 ng/mL or 100 nmol/L. "
- "Notwithstanding outdoor training time during peak sunlight and geographic location, skin color, adiposity, sunscreen use, and choice of athletic clothing will impact on the vitamin D status of athletes (Larson-Meyer & Willis, 2010). Willis et al. (2008) recommend that athletes should aim to achieve a serum 25(OH)D of at least 75–80 nmol/L and that daily supplementation with 1000–2000 IU (25–50 μg) vitamin D may be required to achieve these levels. Higher doses given less frequently can also maintain optimal 25(OH)D levels (e.g., 50 000 IU vitamin D 2 once every 2 weeks has been shown to maintain concentrations of 25(OH)D > 75 nmol/L; Holick, 2011). "
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A high prevalence of vitamin D insufficiency/deficiency, which may impact on health and training ability, is evident among athletes worldwide. This observational study investigated the vitamin D status of elite Irish athletes and determined the effect of wintertime supplementation on status.
Serum 25-hydroxyvitamin D [25(OH)D], calcium, and plasma parathyroid hormone were analyzed in elite athletes in November 2010 (17 boxers, 33 paralympians) or March 2011 (34 Gaelic Athletic Association [GAA] players). A subset of boxers and paralympians (n = 27) were supplemented during the winter months with either 5,000 IU vitamin D3/d for 10-12 weeks or 50,000 IU on one or two occasions. Biochemical analysis was repeated following supplementation.
Median 25(OH)D of all athletes at baseline was 48.4 nmol/L. Vitamin D insufficiency/deficiency (serum 25(OH)D <50 nmol/L) was particularly evident among GAA players (94%) due to month of sampling. Wintertime supplementation (all doses) significantly increased 25(OH)D (median 62.8 nmol/L at baseline vs. 71.1 nmol/L in April or May; p = .001) and corrected any insufficiencies/deficiencies in this subset of athletes. In contrast, 25(OH)D significantly decreased in those that did not receive a vitamin D supplement, with 74% of athletes classed as vitamin D insufficient/deficient after winter, compared with only 35% at baseline.
This study has highlighted a high prevalence of vitamin D insufficiency/ deficiency among elite Irish athletes and demonstrated that wintertime vitamin D3 supplementation is an appropriate regimen to ensure vitamin D sufficiency in athletes during winter and early spring.
Available from: Aleksandra Zagrodna (Kopeć)
- "Galan et al. (2012) showed that after the winter period (early February) 64% of players had 25(OH)D3 levels below 30 ng/ml and only 14.3% had normal levels. Analyses conducted in various groups of athletes such as runners (Lethonen -Veromaa et al., 1999; Willis et al., 2008), gymnasts (Lethonen - Veromaa et al., 1999; Lovell, 2008) or amateur athletes (Halliday et al., 2011) revealed that 37 – 100% of the subjects had 25(OH)D3 deficiency and 1 – 83% of the subjects had 25(OH)D3 insufficiency. These results depended on the sports discipline, study period and geographic location. "
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ABSTRACT: Vitamin D is synthesised in the skin during exposure to sunlight. The fundamental roles of vitamin D are the regulation of calcium and phosphate metabolism and bone mineralisation. Low vitamin D levels in athletes may adversely affect their exercise capabilities. The aim of our study was to investigate changes in serum levels of 25(OH)D3, calcium and bone turnover markers in football players in two training periods differing in the exposure to sunlight (after the summer period and after the winter period). We investigated 24 Polish professional soccer players. Serum levels of the following parameters were determined: 25(OH)D3, calcium, osteocalcin (OC), parathormone (PTH), procollagen type I N - terminal peptide (P1NP), and beta - CrossLaps (beta - CTx). We showed significantly higher levels of 25(OH)D3 and calcium and lower levels of PTH after the summer period versus the winter period. No significant differences in the levels of bone turnover markers were found. Furthermore, we did not observe any significant correlations between the levels of 25(OH)D3 and other parameters. Normal levels of 25(OH)D3 were observed in 50% of the players after the summer period and only in 16.7% of the players after the winter period. It is justified to measure the levels of 25(OH)D3, calcium and PTH in soccer players, especially after the winter period, when the exposure to sunlight is limited.
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