ISSN: 2641-3043
J Food Sci Nutr The
Review Article       Open Access      Peer-Reviewed

Vitamin D - A Probable Performance Boosting Mediator in Athletes

Amit Bandyopadhyay*, Ishita Bhattacharjee and Anindita Singha Roy

Sports and Exercise Physiology Laboratory, Department of Physiology, University of Calcutta, University Colleges of Science & Technology, 92, A.P. C. Road, Kolkata: 700009, INDIA
*Corresponding author: Amit Bandyopadhyay, M.Sc., Ph.D., FICN, Assistant Professor, Sports and Exercise Physiology Laboratory, Department of Physiology, University of Calcutta, University College of Science and Technology, 92, A. P. C. Road, Kolkata, 700009, India, Tel: +91 33 23508386; (Extn 317); Fax: +91 33 23519755; E-mail: bamit74@yahoo.co.in
Received: 17 December, 2016 | Accepted: 29 December, 2016 | Published: 30 December, 2016
Athletic performance; Fitness profile; Immunity; Muscle hypertrophy and hyperplasia; UV rays, Vit–D.

Cite this as

Bandyopadhyay A, Bhattacharjee I, Roy AS (2016) Vitamin D - A Probable Performance Boosting Mediator in Athletes. J Food Sci Nutr The 2(1): 019-024. DOI: 10.17352/jfsnt.000005

Vitamin D positively influences athletic performance by improving strength, power, speed, cardio respiratory fitness, reaction time, coordination, and body composition. Debatable opinion exists regarding the exact role of Vitamin–D (Vit–D) which is supplemented in the form of Vit–D3 to improve sports performance. Proper dose of Vit–D3 supplementation among athletes has been recommended since lower Vit–D level is a common feature in athletes. Direct association of Vit–D level and athletic performance has not yet been confirmed. The present attempt was aimed to review the concept of Vit–D induced improvement in athletic performance and also to explore the guidelines of Vit–D3 supplementation improve health and performance in adolescent athletes.

Methods or strategy adopted to search literatures: A systematic analysis of the scientific literature was undertaken to find as many studies as possible that reported the information related to Vit–D. Studies published during 1975 to 2013 were searched. The key words used in this search procedure were Vit–D supplementation, athletes, dose of Vit–D, mechanism of action of Vit–D and synthesis of Vit–D. Only published, full-text manuscripts written in the English language were included. A systematic literature search has been followed in different internet databases, viz., google, MEDLINE, Scopus, Web of Science and Researchgate. Various hard copies of text books and journals were also consulted from different institutional libraries to ensure exhaustive literature search. This entire search procedure fetched 439 articles which underwent initial screening process. Reference lists of the initially screened articles were also screened and relevant articles were again considered and further screened for the purpose of this review. All the abstracts were thoroughly read to judge its suitability. When the title and abstract provided insufficient data to ensure an article’s eligibility, the full text paper was retrieved and analysed. After that the article was consulted if it provided explicitly any new information, otherwise it was excluded or used as a supportive reference. The article which was found irrelevant in the context of the objective of the present review was also excluded.

Introduction

Vit–D3 supplementation may play a crucial role for optimal performance in athletes as Vit–D deficiency has become worldwide epidemic among children, adolescents and adults [1-10]. Calcitriol, the activated form of Vit–D is a pluripotent pleiotropic secosteroid hormone which regulates more than thousands of genes in human involving cellular growth, cell turnover and regeneration, immune function, protein synthesis, hormone synthesis [11-13].

The key function of Vit–D is to maintain physiological homeostasis of calcium and phosphorus under the patronage of intestine, kidney, parathyroid gland, bone and skeletal muscle [14]. Deficiency of Vit–D may affect skeletal health involving bone and muscle [15,16], as well as may be correlated to chronic diseases like cancer, infectious diseases, diabetes, hypertension, cardio-vascular diseases, inflammatory bowel disease, depression, osteoarthritis, autoimmune diseases like rheumatoid arthritis, etc [17,18].

The discovery of Vit–D receptor in muscle cells signifies its important role in muscle tissue function, and could also have impact on athletic performance and injury like stress fractures [12] But less is known about the status of Vit-D in adolescent athletes. Emerging evidences suggest that Vit-D is imperative to maintain and improve muscle protein synthesis, muscle strength, muscle size, reaction time, posture and balance, coordination, endurance, inflammation, bone health, immune function, and inflammatory responses which are essential component for building optimal performance level [11,19-22].

However, definite information about the exact role played by Vit–D following its supplementation in improving athletic performance has not yet been clearly discussed. Specific requirement of Vit–D, i.e., the dose of Vit–D for athletes is not exactly known [35].

The present review has been focused to investigate the probable underlying mechanisms about the potential association between Vit–D concentration and athletic performance as well as to summarize the current recommendations regarding Vit–D3 supplementation to improve the general health and athletic performance in adolescent athletes.

Is there any disparity between Vit–D deficiency, insufficiency, sufficiency?

The best indicator of Vit-D status is the concentration of serum 25(OH)D [17,20,23], However, optimal serum 25(OH)D concentrations is debatable and have yet to be defined but proposed to fall in the range of 40-70 ng/Ml [20,28] (Table 1).

Sources of Vit-D in athletes [20-22]

Pathway of Vit-D derivative synthesis

On exposure of skin to UVB radiation 7-dehydrocholesterol which is present in the plasma membrane of epidermis and dermis is converted to previtamin D3 (precholecalciferol). This previtamin D3 isomerizes to vitamin D3 (cholecalciferol) within two to three days [30]. Vit-D then binds with Vit-D binding protein (VDBP) and migrates into the capillary bed of dermis and into circulation and is consequently hydroxylated in the liver by enzymes of the cytochrome P-450 system to 25(OH)D [16,17]. Further hydroxylation in kidney tubules to the hormonally active form, 1,25(OH)2D, is driven by parathyroid hormone (PTH) when serum calcium and phosphate concentrations fall below the physiological range [16-18] (In addition to this, many extra-renal cells (and tissues), including macrophages, brain, colon, breast, and others, have the enzymatic machinery (1-α-hydroxylase) to produce 1,25(OH)2D locally [16,20,31].

Etiology of Vit-D deficiency

The etiology of Vit-D deficiency is multifactorial. In spite of adequate dietary intake of Vit-D it may be deficient due to its malabsorption in the intestine [14,32]. Other causative factors include geographical location that limits the availability of UVB rays, climate and different seasons e.g., summer, winter, spring, etc., clothing, skin pigmentation, age, indoor practice, higher adiposity, strict vegan or vegetarian dietary nature, etc.. [17,20,33-37]. Hence supplementation of Vit-D3 is necessary and has already been widely accepted along with higher dietary intake and UVB exposure to maintain the normal level of Vit-D in human body [20,23,25,38,39].

Physiological Requirement of Vit-D

According to the National Institute of Health [40] and other guidelines [41] the healthy requirement of Vit–D is as follows: (Tables 2,3).

Dietary intake recommendation for Vit-D increases with age, pregnancy and lactation [12]. There is a controversy between the Recommended Dietary Allowance (RDA) of Vit-D among experts [16,25,34,38].

The optimal Sports health benefits threshold of Vit-D is still unknown, however, 25(OH)D levels of 50ng/mL and above is sufficient for peak neuromuscular performance [19,24,25]. It is also important to recognize the threshold requirement of Vit–D sine it is highly individualized due to the variations of individual diet, endogenous synthesis and storage capacity [35].

Supplementation protocol of Vitamin D3 for athletes

Athletes having 25(OH)D level < 30ng/ml is Vit-D deficient. Now-a-days Vit-D3 supplementation is accepted widely, hence according to the supplementation protocol a Vit-D deficient athlete should receive a short-term high dose “loading dose” 50,000 IU of Vitamin per week for 8 weeks [17] to replenish stores more rapidly. After about 90 days of supplementation a steady state level of 25(OH)D is reached and retesting is required at this level [43]. If results are still < 30ng/ml, repetition of the same supplementation protocol is necessary, and the serum level of 25(OH)D should be tested again [17]. Once the sufficient level reached, a maintenance level of supplementation of 1000-5000 IU per day as required should be continued as directed by The National Academy of Science [44].

According to The National Academy of Science the upper levels of intake of Vit-D3 and calcium for adolescents and adults is 4000 IU per day and it is unnecessary to exceed this level if sufficient Vit-D is present in serum [18,44-48]. There is another advantage of Sun exposure over Vit-D3 supplementation because cutaneous synthesis has a negative feedback loop preventing Vit-D accumulation and toxicity [49,50]. Oral dosing with 10 000 IU per day is the tolerable upper-intake level without toxicity [46,51-53]. But it is not recommended to take 10000 IU per day with incremental increases in 25(OH)D by 70 ng/ml, well over the amount of 50ng/ml is needed for optimal sports health benefits [46]. Alternatively long-term Vit-D sufficiency can be maintained easily by taking 50 000 IU of Vit-D3 once or twice a month [9].

Physiological effects of Vit-D

A strong correlation between Vit-D sufficiency and optimal muscle function has been widely reported [16,22,54-57] with the fact that Vit-D exerts its physiological action in autocrine and endocrine mode [12]. The autocrine pathway appears to be essential for skeletal muscle function [25,58], through which more than 80% of Vit-D is utilized in the body [58]. Receptor mediated Vit-D action in the cells has been established that regulates hundreds of gene expression especially within the muscle cells where it not only promotes muscle hypertrophy but also modifies the transportation of calcium in the sarcoplasmic reticulum, but this mechanism is yet to be proved in human studies [11,15,17,19,54,58,60-64,68]. Physical performance changed proportionately with the dose of 25(OH)D [19,69,71-79]. Correlations were stronger for reaction time, balance, and timed tests of physical performance. Direct relationship of Vit D with strength, power and athletic performance indicated that Vit D has an influential role to develop muscle power and force which in turn improve the athletic performance [90]. Maintaining adequate Vit-D status is important to improve strength, power, and speed performance by facilitating the genomic and non-genomic actions of Vit-D in skeletal muscle [11].

Vit–D is essential for maintaining bone density, bone growth and bone remodeling [85,88]. Calcium absorption and osteoclast activity in the bone are also influenced by Vit–D via its endocrine activity mediated via Parathyroid and Thyroid glands [35].

Significant positive correlations have also been reported between Vit-D concentration and cardiorespiratory fitness expressed in terms of VO2max [91-93]. Significantly higher values of VO2max in athletes and non-athletes during summer than in the winter was also attributed to the fact of higher Vit – D sysnthesis in summer [94,95]. Vit-D was also linked with UVB radiation to improve cardio-respiratory fitness [11]. These studies concluded that athletes have better cardiorespiratory endurance when they are able to maintain an adequate Vit-D status.

Insufficient Vit-D concentrations are associated with an unfavorable body composition in otherwise healthy individuals [102]. Vit-D concentrations were inversely correlated with percent body fat and suppressing parathyroid hormone levels by attaining an adequate Vit-D status may reduce adiposity in non-athletes and athletes alike and help them to achieve their ideal body composition [103].

Vit-D status among athletes

There are several studies that documented a high incidence of Vit-D insufficiency and deficiency in the general population worldwide, only a handful of studies have focused on athletes listed in Table 1.

Though the findings varies mainly due to the lack of sun exposure and to a less extent due to geographical location (latitude) and gender, major risk factors for Vit-D insufficiency occurs to the indoor athletes and those who avoid peak daylight hours, despite of latitudinal location [46,47,89,105-108].

Conclusion

The review summarizes and supports the hypothesis that Vit–D may have some impact on physiological system to improve the athletic performance. Exposure to UV–B radiation seems to improve various measurements of athletic performance, but adequate randomized controlled trials are essential to land to a specific conclusion. During summer greater sun exposure may facilitate cutaneous Vit–D synthesis and consequent reflection in athletic performance is speculated. However, other factors like indoor practicing has secondary influence on Vit–D production. It is also evident that Vit-D3 supplementation reverses hypertrophy and hyperplasia of Type II muscle fibers in Vitamin D deficient individuals. Several large community-based cross-sectional studies of neuromuscular functioning and serum Vit–D found positive associations, but prospective cohort studies are conflicting, raising the possibility of reverse causation.

From the above evidences it may be concluded that adequate Vit–D3 supplementation may improve athletic performance in Vit–D deficient athletes. If such a treatment effect exists, the largest improvements in performance will probably occur in those with the lowest levels; that is, a significant improvement in athletic performance may occur when levels increase from 15–30 ng/mL, but less improvement will occur when levels increase from 30–50 ng/mL. However, an ideal Vit–D level is needed for peak athletic performance that needs confirmation through well designed experimental interventions explaining the magnitude, type of athletic performance variables (reaction time, muscle strength, balance, coordination, or endurance) that is improved the most.

  1. Andersen R, Molgaard C, Skovgaard L, Brot CCashman KD, et al. (2005) Teenage girls and elderly women living in northern Europe have low winter vitamin D status. Euro J Clin Nutr 59: 533-541. Link: https://goo.gl/SDbjjr
  2. Binkley N, Novotny R, Krueger D, Kawahara T, Daida YG, et al. (2007) Low vitamin D Status despite abundant sun exposure. J Clin Endocrinol Metab 92: 2130-2135. Link: https://goo.gl/lvSpt0
  3. Gordon C, DePeter K, Feldman H, Grace EEmans SJ (2004) Prevalence of vitamin D deficiency among healthy adolescents. Arch Pediatr Adolesc Med 158: 531-537. Link: https://goo.gl/2AMDZL
  4. Hannan MT, Litman HJ, Araujo AB, McLennan CEMcLean RR, et al.(2008) Serum 25-Hydroxyvitamin D and bone mineral density in a racially and ethnically diverse group of men. J Clin Endocrinol Metab 93: 40-46. Link: https://goo.gl/KP1EWC
  5. Hashemipour S, Larijani B, Adibi H, Javadi E, Sedaghat M, et al. (2008) Vitamin D deficiency and causative factors in the population of Tehran. BMC Public Health 4: 38. Link: https://goo.gl/VBm9XI
  6. Hypponen E, Power C (2007) Hypovitaminosis D in British adults at age 45 y: nationwide cohort study of dietary and lifestyle predictors. Am J Clin Nutr 85: 860-868. Link: https://goo.gl/kVR7fw
  7. Macfarlane GJ, Palmer B, Roy D, Afzal CSilman AJ, et al. (2005) An excess of widespread pain among South Asians: are low levels of vitamin D implicated? Ann Rheum Dis 64: 1217-1129. Link: https://goo.gl/FmeP8i
  8. Nowson CA, Margerison C (2002) Vitamin D intake and vitamin D status of Australians. Med J Aust 177: 149-152. Link: https://goo.gl/aYy9uS
  9. Plotnikoff GA, Quigley JM (2003) Prevalence of severe hypovitaminosis D in patients with persistent, nonspecific musculoskeletal pain. Mayo Clin Proc 78: 1463-1470. Link: https://goo.gl/owyOEd
  10. Rockell J, Green T, Skeaff C, Whiting SJTaylor RW, et al. (2005) Season and ethnicity are determinants of serum 25-hydroxyvitamin D concentrations in New Zealand children aged 5-15 y. J Nutr 135: 2602-2608. Link: https://goo.gl/XZSwi7
  11. Cannell JJ, Hollis BW, Sorenson MB, Taft TN, Anderson JJ (2009) Athletic performance and vitamin D. Med Sci Sports Exerc 41: 1102-1110. Link: https://goo.gl/oznXek
  12. Ogan D, Pritchett K (2013) Vitamin D and the Athlete: Risks, Recommendations, and Benefits. Nutrients5: 1856-1868. Link: https://goo.gl/jecifd
  13. Tavera-Mendoza LE, White JH (2007) Cell defenses and the sunshine vitamin. Sci Am 297: 62-65, 68-70,72. Link: https://goo.gl/ixTWzF
  14. Angeline ME, Gee AO, Shindle M, Warren RFRodeo SA (2013) The Effects of Vitamin D Deficiency in Athletes. Am J Sports Med41: 461-464. Link: https://goo.gl/iIwGR8
  15. Hamilton B (2011) Vitamin D and Athletic Performance: The Potential Role of Muscle. Asian Journal of Sports Medicine2: 211-219. Link: https://goo.gl/BU8u3S
  16. Holick MF (2008) The vitamin D deficiency pandemic and consequences for nonskeletal health: mechanisms of action. Mol Aspects Med 29: 361-368. Link: https://goo.gl/3Jk3z4
  17. Holick MF (2007) Vitamin D deficiency. N Engl J Med 357: 266-281. Link: https://goo.gl/rLd4AZ
  18. Zittermann A (2003) Vitamin D in preventive medicine: are we ignoring the evidence? Br J Nutr 89: 552-572. Link: https://goo.gl/bY8Aga
  19. Bischoff-Ferrari HA, Dietrich T, Orav EJ, Hu FBZhang Y, et al. (2004) Higher 25-hydroxyvitamin D concentrations are associated with better lower-extremity function in both active and inactive persons aged 9 or =60 y. Am J Clin Nutr80: 752-758. Link: https://goo.gl/qRivEz
  20. Cannell JJ, Hollis BW, Sorenson MB, Taft TN, Anderson JJ (2009) Athletic performance and vitamin D. Med Sci Sports Exerc 41: 1102-1110. Link: https://goo.gl/76GMpW
  21. Cannell JJ, Hollis BW, Zasloff M, Heaney RP (2008) Diagnosis and treatment of vitamin D deficiency. Expert Opin Pharmacother 9: 107-118. Link: https://goo.gl/4opHbv
  22. Cannell JJ, Zasloff M, Garland CF, Scragg R, Giovannucci E (2008a) On the epidemiology of influenza. Virol J 5: 29. Link: https://goo.gl/VzLRCi
  23. Holick MF (2009) Vitamin D and health: Evolution, biologic functions, and recommended dietary intakes for vitamin D. Clin Rev Bone Min. Metab 7: 2–19. Link:
  24. Hollis BW (2005) Circulating 25-hydroxyvitamin D levels indicative of vitamin D sufficiency: implications for establishing a new effective dietary intake recommendation for vitamin D.J Nutr 35: 317-322. Link: https://goo.gl/JlcJRL
  25. eaney RP (2008) Vitamin D in health and disease. Clin J Am Soc Nephrol 3: 1535–1541. Link: https://goo.gl/zI86SF
  26. Holick MF (2005) The vitamin D epidemic and its health consequences. J Nutr 135: 2739–2748. Link: https://goo.gl/QxkvZD
  27. Willis KS, Peterson NJ, Larson-Meyer DE (2008) Should we be concerned about the vitamin D status of athletes? Int J Sport Nutr Exerc Metab 18: 204–224. Link: https://goo.gl/pjTehR
  28. Bischoff-Ferrari HA, Giovannucci E, Willett WC, Dietrich T, Dawson-Hughes B (2006) Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes. Am J Clin Nutr 84: 18–28. Link: https://goo.gl/kBqEzs
  29. NIH Office of Dietary Supplements. (2011, September 21). Dietary Supplement Fact Sheet: Vitamin D. Retrieved from. Link: https://goo.gl/V4KQOv
  30. Holick MF (1987) Photosynthesis of vitamin D in the skin: effect of environmental and life-style variables. Fed Proc 46: 1876-1882. Link: https://goo.gl/qEIygY
  31. SJ, Calvo MS (2005) Dietary recommendations to meet both endocrine and autocrine needs of Vitamin D. J Steroid Biochem Mol Biol 97: 7-12. Link: https://goo.gl/GWQBpy
  32. Whiting SJ, Calvo MS (2005) Dietary recommendations to meet both endocrine and autocrine needs of Vitamin D. J Steroid Biochem Mol Biol 97: 7-12. Link: https://goo.gl/BkbWh8
  33. Basu TK, Donaldson D (2003) Intestinal absorption in health and disease: micronutrients. Best Pract Res Clin Gastroenterol 17: 957-979. Link: https://goo.gl/Yf4tuh
  34. Ginde AA, Liu MC, Camargo CA Jr. (2009) Demographic differences and trends of vitamin D insufficiency in the US population, 1988-2004. Arch Intern Med169: 626 –632. Link: https://goo.gl/opJnog
  35. Larson-Meyer DE, Willis KS (2010) Vitamin D and athletes. Curr Sports Med Rep 9: 220–226. Link: https://goo.gl/OIrqne
  36. Looker AC, Pfeiffer CM, Lacher DA, Schleicher RL, Picciano MF, et al. (2008) Serum 25-hydroxyvitamin D status of the US population: 1988-1994 compared with 2000-2004. Am J Clin Nutr 88: 1519-1527. https://goo.gl/x3WCRU
  37. Wortsman J, Matsuoka LY, Chen TC, Lu Z, Holick MF (2000) Decreased bioavailability of vitamin D in obesity. Am J Clin Nutr 72: 690-693. Link: https://goo.gl/yGIQi4
  38. Moyad MA (2009) Vitamin D: A rapid review. Dermatol Nurs 21: 25–30, 55. Link: https://goo.gl/nXMQLA
  39. Shuler FD, Wingate MK, Moore H, Giangarra C (2012) Sports Health benefits of Vitamin D. Sports Health 4: 496-501. Link: https://goo.gl/C9OPmL
  40. News from the National Academies (2012) IOM report sets new dietary intake levels for calcium and Vit-D to maintain health and avoid risks associated with excess. Record ID=13050. Accessed January 22. Link: https://goo.gl/nNPNWw
  41. Ross AC, Taylor CL, Yaktine AL, Del Valle HB (2011) Dietary Reference Intakes for Calcium and Vitamin D. The National Academies Press, Washington (DC). Link: https://goo.gl/X37n7I
  42. Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, et al. (2011) Evaluation, treatment, and prevention of vitamin D deficiency: An endocrine society clinical practice guideline. J Clin Endocrinol Metab 96: 1911–1930. Link: https://goo.gl/v3YVgT
  43. Heaney RP, Davies KM, Chen TC, Holick MF, Barger-Lux MJ (2003) Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol. Am J Clin Nutr 77: 204–210. Link: https://goo.gl/0OOzqn
  44. The National Academy of Science. Link: https://goo.gl/cGjOfu
  45. Nielsen FH, Lukaski HC (2006) Update on the relationship between magnesium and exercise. Magnes Res 19: 180-189. Link: https://goo.gl/1cSdE7
  46. Lovell G (2008) Vitamin D status of females in an elite gymnastics program. Clin J Sport Med 18: 159–161. Link: https://goo.gl/sXgFdw
  47. Halliday TM, Peterson NJ, Thomas JJ, Kleppinger K, Hollis BW, et al. (2010) Vitamin D status relative to diet, lifestyle, injury and illness in college athletes. Med Sci Sport Exerc 42: 335–343. Link: https://goo.gl/hPRMZ0
  48. Ziegler P, Nelson JA, Barratt-Fornell A, Fiveash L, Drewnowski A, et al. (2001) Energy and macronutrient intakes of elite figure skaters. J Am Diet Assoc 101: 319-325. Link: https://goo.gl/ERGbvb
  49. Matsuoka LY, Ide L, Wortsman J, MacLaughlin JA, Holick MF (1987) Sunscreens suppress cutaneous vitamin D3 synthesis. J Clin Endocrinol Metab 64: 1165-1168. Link: https://goo.gl/TCpsUu
  50. Ziegler P, Nelson JA, Barratt-Fornell A, Fiveash L, Drewnowski A (2001) Energy and macronutrient intakes of elite figure skaters. J Am Diet Assoc 101: 319-325. Link: https://goo.gl/aaSxjj
  51. Heaney RP (2005) The vitamin D requirement in health and disease. J Steroid Biochem Mol Biol 97: 13–19. Link: https://goo.gl/Rp3OWj
  52. Koutkia P, Lu Z, Chen TC, Holick MF (2001) Treatment of vitamin D deficiency due to Crohn’s disease with tanning bed ultraviolet B radiation. Gastroenterology 121: 1485-1488. Link: https://goo.gl/UVhxWQ
  53. Maimoun L, Manetta J, Couret I, Dupuy AMMariano-Goulart D (2006) The intensity level of physical exercise and the bone metabolism response. Int J Sports Med 27: 105-111. Link: https://goo.gl/rpKqMP
  54. Bartoszewska M, Kamboj M, Patel DR (2010) Vitamin D, muscle function, and exercise performance. Pediatr Clin North Am 57: 849 –861. Link: https://goo.gl/JdN2Bq
  55. Ceglia L (2009) Vitamin D and its role in skeletal muscle. Curr Opin Clin Nutr Metab Care 12: 628 –633. Link: https://goo.gl/Dfy8Y6
  56. Ceglia L (2008) Vitamin D and skeletal muscle tissue and function. Mol Aspects Med 29: 407–414. Link: https://goo.gl/mWLaVE
  57. Dirks-Naylor AJ, Lennon-Edwards S (2011) The effects of vitamin D on skeletal muscle function and cellular signaling. J Steroid Biochem Mol Biol 125: 159 – 168. Link: https://goo.gl/ql4waH
  58. Ceglia L, Harris SS (2013) Vitamin D and its role in skeletal muscle. Calcif Tissue Int 92: 151–162. Link: https://goo.gl/jhSu09
  59. Birge SJ and Haddad JG (1975) 25- hydroxycholecalciferol stimulation of muscle metabolism. J Clin Invest 58: 1100-1107. Link: https://goo.gl/2yqX8i
  60. Bischoff-Ferrari HA (2012) Relevance of vitamin D in muscle health. Rev Endocr Metab Disord 13: 71–77. Link: https://goo.gl/44QGaw
  61. Campbell PMF, Allain TJ (2006) Muscle strength and vitamin D in older people. Gerontology 52: 335–338. Link: https://goo.gl/0L3ZDE
  62. Girgis CM, Clifton-Bligh RJ, Hamrick MW, Holick MF, Gunton JE (2013) The roles of vitamin D in skeletal muscle: Form, function, and metabolism. Endocr Rev 34: 33–83. Link: https://goo.gl/bmI35w
  63. Holick MF, Chen TC (2008) Vitamin D deficiency: a worldwide problem with health consequences. Am J Clin Nutr 87: 1080-1086. Link: https://goo.gl/PGfyQx
  64. Marantes I, Achenbach SJ, Atkinson EJ, Khosla S, Melton LJ, et al. (2011) Is vitamin D a determinant of muscle mass and strength? J Bone Miner Res 26: 2860–2871. Link: https://goo.gl/5sGhFO
  65. Foo LH, Zhang Q, Zhu K, Ma G, Hu X, et al. (2009) Low vitamin D status has an adverse influence on bone mass, turnover, and muscle strength in adolescent female girls. J Nutr 139: 1002–1007. Link: https://goo.gl/DE4tZx
  66. Wacker M, Holick MF(2013) Vitamin D—Effects on skeletal and extraskeletal health and the need for supplementation. Nutrients 5: 111–148. Link: https://goo.gl/2GverX
  67. Wang Y, DeLuca HF (2011) Is the vitamin D receptor found in muscle? Endocrinology 152: 354–363. Link: https://goo.gl/OGCPWT
  68. Young A, Edwards RHT, Jones DA, Brenton DP (1981) Quadriceps muscle strength and fibre size during treatment of osteomalacia. In: Stokes IAF, ed. Mechanical Factors and the Skeleton, John Libbey, London, UK, 137-145.
  69. Pfeifer M, Begerow B, Minne HW, Schlotthauer T, Pospeschill, M, et al. (2001) Vitamin D status, trunk muscle strength, body sway, falls, and fractures among 237 postmenopausal women with osteoporosis. Exp Clin Endocrinol Diabetes 109: 87–92. Link: https://goo.gl/F6qzCk
  70. Ahmed W, Kahn N, Glueck CJ, Pandey SWang P, et al. (2009) Low serum 25(OH) vitamin D levels (<32ng/ml) are associated with reversible myositis- myalgia in statin-treated patients. Transl Res 153: 11–16. Link: https://goo.gl/eeO4YF
  71. Wassner SJ, Li JB, Sperduto A, Norman ME (1983) Vitamin D deficiency, hypocalcemia, and increased skeletal muscle degradation in rats. J Clin Invest 72: 102-112. Link: https://goo.gl/VRc9xS
  72. Visser M, Deeg DJ, Lips P (2003) Longitudinal Aging Study Amsterdam. Low vitamin D and high parathyroid hormone levels as determinants of loss of muscle strength and muscle mass (sarcopenia): the Longitudinal Aging Study Amsterdam. J Clin Endocrinol Metab 88: 5766-5772. Link: https://goo.gl/cRVPG3
  73. Zamboni M, Zoico E, Tosoni P, Zivelonghi A, Bortolani A, et al. (2002) Relation between vitamin D, physical performance, and disability in elderly persons. J Gerontol A Biol Sci Med Sci 57: M7–M11. Link: https://goo.gl/2r6Asq
  74. Szulc P, Duboeuf F, Marchand F, Delmas PD (2004) Hormonal and lifestyle determinants of appendicular skeletal muscle mass in men: the MINOS study. Am J Clin Nutr 80: 496–503. Link: https://goo.gl/xfGrlI
  75. Iannuzzi-Sucich M, Prestwood KM, Kenny AM (2002) Prevalence of sarcopenia and predictors of skeletal muscle mass in healthy, older men and women. J Gerontol A Biol Sci Med Sci 57: 772–777. Link: https://goo.gl/VQNs3o
  76. Kenny AM, Biskup B, Robbins B, Marcella G, Burleson JA (2003) Effects of vitamin D supplementation on strength, physical function, and health perception in older, community-dwelling men. J Am Geriatr Soc 51: 1762–1767. Link: https://goo.gl/5Rs7LA
  77. Glerup H, Mikkelsen, K., Poulsen, L., Hass EOverbeck S, et al. (2000) Hypovitaminosis D myopathy without biochemical signs of osteomalacic bone involvement. Calcif Tissue Int 66: 419–424. Link: https://goo.gl/zuQyd1
  78. Bischoff HA, Stahelin HB, Dick W, Akos RKnecht M, et al. (2003) Effects of vitamin D and calcium supplementation on falls: a randomized controlled trial. J Bone Miner Res 18: 343–351. Link: https://goo.gl/Avyuzb
  79. Bischoff HA, Stahelin HB, Urscheler N, Ehrsam RVonthein R, et al. (1999) Muscle strength in the elderly: its relation to vitamin D metabolites. Arch Phys Med Rehabil 80: 54–58. Link: https://goo.gl/ZaKgxJ
  80. Allen R, Cureton T (1945) Effects of ultraviolet radiation on physical fitness. Arch Phys Med 10: 641–644. Link: https://goo.gl/X8upAe
  81. Gerdhem P, Ringsberg KA, Obrant KJ, Akesson K (2005) Association between 25-hydroxy vitamin D levels, physical activity, muscle strength and fractures in the prospective population-based OPRA Study of Elderly Women. Osteoporos Int 16: 1425–1431. Link: https://goo.gl/R0gv4q
  82. Wicherts IS, van Schoor NM, Boeke AJ, Visser MDeeg DJ, et al. (2007) Vitamin D status predicts physical performance and its decline in older persons. J Clin Endocrinol Metab 92: 2058–2065. Link: https://goo.gl/b6XqMJ
  83. Faulkner KA, Cauley JA, Zmuda JM, Landsittel DPNewman AB, et al. (2006) Higher 1,25-dihydroxyvitamin D3 concentrations associated with lower fall rates in older community-dwelling women. Osteoporos Int; 17: 1318–1328. Link: https://goo.gl/9EbyXA
  84. Verreault R, Semba RD, Volpato S, Ferrucci L, Fried LP, et al .(2002) Low serum Vitamin D does not predict new disability or loss of muscle strength in older women. J Am Geriatr Soc 50: 912–92*17. Link: https://goo.gl/LmGY6E
  85. DeLuca HF (2004) Overview of general physiologic features and functions of vitamin D. Am J Clin Nutr 80: 1689–1696. Link: https://goo.gl/Nd5oSj
  86. Powers S, Nelson WB, Larson-Meyer E (2011) Antioxidant and Vit-D supplements for athletes: sense or non-sense. J Sports Sci 29: 47-55. Link: https://goo.gl/XWbMVh
  87. Ruohola J, Laaksi I, Ylikomi T, Mattila VMSahi T, (2006) Association between serum 25(OH)D Concentrations and bone stress fractures in finnish young men. J Bone Min Res 21: 1483-1488. Link: https://goo.gl/fgc4Pd
  88. Lappe J, Cullen D, Haynatzki G, Recker R, Ahlf R, et al. (2008) Calcium and Vit-D supplementation decreased incidence of stress fractures in female navy recruits. J Bone Miner Res 23: 741–749. Link: https://goo.gl/WxSjCi
  89. Valimaki VV, Alfthan H, Lehmuskallio E, Loyttyniemi E, Sahi T, et al. (2004) Vitamin D status as a determinant of peak bone mass in young Finnish men. J Clin Endocr Metab 89: 76–80. Link: https://goo.gl/EcFBew
  90. Ward KA, Das G, Berry JL, Roberts SARawer R, et al. (2009) Vitamin D status and muscle function in post-menarchal adolescent girls. J Clin Endocrinol Metab 94: 559-563. Link: https://goo.gl/umftCm
  91. Mowry D, Costello M, Heelan K (2009) Association among cardiorespiratory fitness, body fat, and bone marker measurements in healthy young females. J Am Osteopathic Association 109: 534–539. Link: https://goo.gl/9ECxlO
  92. Al Mheid I, Ramadan R, Kavtaradze N, Morris A, Ali S et al (2009) Vitamin D levels are associated with exercise capacity and measures of endothelial function in healthy humans. Circulation 120: 551. Link: https://goo.gl/utNqFR
  93. Ardestani A, Parker B, Mathur S, Clarkson P, Pescatello L, et al. (2011) Am J Cardiol107: 1246–1249. Link: https://goo.gl/8GoQ66
  94. Erikssen J, Rodahl K (1979) Seasonal variation in work performance and heart rate response to exercise. A study of 1,835 middle-aged men. Eur J Appl Physiol 42: 133-140. Link: https://goo.gl/BjUHFz
  95. Svedenhag J, Sjodin B (1985) Physiological characteristics of elite male runners in and off-season. Can J Appl Spor Sci 10; 127-33. Link: https://goo.gl/oLhjkU
  96. Clark M, Lucett S (2009) National Academy of Sports Medicine NASM essentials of sports performance training. In: Lippincott Williams & Wilkins, Philadelphia, PA, USA. 101-107. Link: https://goo.gl/pxatM9
  97. Bartali B, Frongillo EA, Guralnik JM, Stipanuk MH, Allore HG (2008) Serum micronutrient concentrations and decline in physical function among older persons. JAMA 299: 308–315. Link: https://goo.gl/WSi4qv
  98. Dhesi J, Jackson SH, Bearne L, Moniz C, Hurley M, et al. (2004) Vitamin D supplementation improves neuromuscular function in older people who fall. Age Ageing 33: 589–595. Link: https://goo.gl/9wQcVf
  99. Harms LR, Burne TH, Eyles DW, McGrath JJ (2011) Vitamin D and the brain. Clinical Endocrinology and Metabolism 25: 657-669. Link: https://goo.gl/zeQwVT
  100. McCann JC, Ames BN (2008) Is there convincing biological or behavioral evidence linking vitamin D deficiency to brain dysfunction? The Journal of the Federation of American Societies for Experimental Biology 22: 982-1001. Link: https://goo.gl/7wjGY7
  101. American College of Sports Medicine (2009) American Dietetic Association, & Dietitians of Canada: Nutrition and Athletic Performance. In: Medicine and Science in Sports and Exercise 41: 709-731.
  102. Kremer R, Campbell PP, Reinhardt T, Gilsanz V (2009) Vitamin D status in its and its relationship to body fat, final height, and peak bone mass in young women. J Clin Endocrinol Metab 94: 67-73. Link: https://goo.gl/tbJlfX
  103. Arunabh S, Pollack S, Yeh, J, Aloia J (2003) Body fat content and 25-Hydroxyvitamin D levels in healthy women. J Clin Endocrinol Metab 88: 157-161. Link: https://goo.gl/fWh1Q5
  104. Halliday TM, Peterson N J, Thomas J J (2011) Vitamin D status relative to diet, lifestyle, injury, and illness in college athletes. Med Sci Sport Exerc 43: 335-343. Link: https://goo.gl/zf4vog
  105. Constantini N, Arieli R, Chodick G, Dubnov-Raz G (2010) High prevalence of vitamin D insufficiency in athletes and dancers. Clin J Sport Med 20: 368-371. Link: https://goo.gl/dU9izE
  106. Hamilton B, Grantham J, Racinais S, Hakim C (2009) Vitamin D deficiency is endemic in Middle Eastern sportsman. Public Health Nutr 10: 1528–1534. Link: https://goo.gl/5EPe6V
  107. Storlie DM, Pritchett K, Pritchett R, Cashman L (2011) 12-Week vitamin D supplementation trial does not significantly influence seasonal 25(OH)D status in male collegiate athletes. Int J Health Nutr 2: 8–13. Link: https://goo.gl/L9JxkS
  108. Willis KS, Smith DT, Broughton KS, Larson-Meyer DE (2012) Vitamin D status and biomarkers of inflammation in runners. Open Access J Sports Med 3: 35–42. Link: https://goo.gl/AUuulQ
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