Are letting your performance down?
Vitamin D’s classical role in bone health is well established, and relatively recent research also indicates a role of this vitamin in cardiovascular health, hypertension, mood disorders, hormone balance, cancer risk, cell growth and inflammation. New research is continuously being published on the beneficial effects of vitamin D, also giving rise to much needed debate on optimal levels of this sunshine vitamin. So it seems the limelight period for vitamin D is far from over.
But for now, let’s look at what current research has to say about the role of vitamin D in strength and athletic performance.
The vitamin D receptor was first identified in rat myoblast cells in 1985 showing that muscle is a direct target organ for 1,25(OH)2D, and this discovery led to further research in this area. In 2001 and 2004, the vitamin D receptor was isolated from human skeletal muscle.
A 2010 study published in the Scandinavian Journal of Medicine & Sciences in Sports concluded that ‘the recognition of both genomic and non-genomic effects of vitamin D in skeletal muscle, with the resultant impact on both calcium metabolism and protein transcription, further illustrates the significance of vitamin D in muscle function’.
A paper published in 2013 recommended a 25(OH)D goal of 40 ng/mL for athletes because at this level, ‘vitamin D begins to be stored in the muscle and fat for future use. Furthermore, at levels below 32 ng/mL, vitamin D is not likely to be readily available for the advanced processes involved in the autocrine pathways, which is the pathway that is most likely to influence performance’.
The correlation between vitamin D and markers of inflammation was examined in 19 endurance-trained male and female runners. The study found that there was a significant inverse association between vitamin D levels and TNF-α concentrations. TNF-α (tumour necrosis factor) is an inflammatory cytokine and higher levels of TNF-α is correlated with increased inflammation. This study found that the higher the levels of vitamin D, the lower the levels of TNF-α.
Levels of vitamin D were assessed in 61 athletes and 31 healthy controls. Over an 8 week trial, the group receiving 5000 IU/day of vitamin D supplementation showed significant improvements in 10-metre sprint times and vertical jump compared to the placebo group (this group received no vitamin D supplementation). The results correlated with increased serum levels of 25(OH)D levels. The study published in the Journal of Sports Science, concluded that it is ‘likely necessary to have 25(OH)D levels above 40ng/mL to significantly improve anaerobic athletic performance’. A 2009 study suggests a minimum level of 50ng/mL for athletic performance.
Significant positive correlation between 25(OH)D concentrations and jumping height and velocity, muscle force and muscle power was seen in a study in 99 post-menarchal 12-14 year old girls in a secondary school. The data shows that muscle contractility is affected by the girls vitamin D status – the higher 25(OH)D concentrations generated more power and so jump height and velocity were increased.
The relationship between 25(OH)D levels and muscle strength in 419 healthy men and women was examined in a 2013 study published in Medicine & Science in Sports & Exercise. Vitamin D was found to be significantly associated with arm and leg muscle strength, with differences between upper and lower body strength possibly attributed to androgenic effects or differences in vitamin D receptor sensitivity.
Research published in the Journal of Sports Science suggests inadequate vitamin D status is detrimental to musculoskeletal performance in UK athletes. The authors found that 62% of the athletes and 73% of the controls had vitamin D blood levels < 20 ng/mL. After supplementation, vitamin D status increased significantly from baseline mean 11 ng/mL to 41 ng/mL in the vitamin D group, with no significant change in the placebo group.
The vitamin D group demonstrated a significant increase in 10 metre sprint times (P = 0.008) and vertical jump height (P=0.008), with no change among the placebo participants.
According to a study published in Medicine & Science in Sports & Exercise, sufficient vitamin D may help muscle mass loss associated with aging. Researchers examined more than 400 adults and found that participants with increased vitamin D levels had greater muscle strength in both arms and legs, even after controlling for age, gender, BMI, and season of vitamin D measurement.
Vitamin D levels were more strongly associated with arm strength, although they were associated with leg strength as well.
A new study in the South African Journal of Sports Medicine recently examined vitamin D levels of UK track and field athletes. This cross-sectional sample of 63 elite UK track athletes included almost 50% males and 50% females and a 50%-50% split for those with dark or fair skin colour. About 70% of the athletes were sprinters or power athletes and the remainder were endurance runners.
Despite the methodological weaknesses of this survey, high prevalence rates of vitamin D deficiency (19%) and vitamin D insufficiency (29%) were reported. Measurements less than 20 ng/ml were defined as deficiency and the range of 20 to 30 ng/ml was set as insufficiency of serum 25(OH)-vitamin D.
The quoted studies above are just a few from the large body of available research demonstrating the beneficial impact of vitamin D on strength and athletic performance. In addition to the above there is wealth of research demonstrating that optimal levels of vitamin D can prevent the risk, and reduce the severity of, stress fractures.
To your lean, healthy, optimised future,
Matt & Dee
1. Simpson R, Thomas G, Arnold A (1985). Identification of 1,25-dihydroxyvitamin D3 receptors and activities in muscle. J Biol Chem. 260:8882–8891
2. Bischoff H, Borchers M, Gudat F, Duermueller U, Theiler R, Stahelin H, Dick W (2001). In situ detection of 1,25-dihydroxyvitamin D3 receptor in human skeletal muscle tissue. Histochem J. 33:19–24
3. Bischoff-Ferrari H, Borchers M, Durmuller U, Stahelin H, Dick W (2004). Vitamin D receptor expression in human muscle tissue decreases with age. J Bone Miner Res. 19:265–269
4. Hamilton B (2010). Vitamin D and Human Skeletal Muscle. Scandinavian Journal of Medicine & Sciences in Sports. 20(2) 182-190
5. Ogan D & Pritchett K (2013). Vitamin D and the Athlete: Risks, Recommendations, and Benefits Nutrients. 5(6)1856-1868
6. Willis KS, Smith DT, Broughton KS & Larson-Meyer DE (2012) Vitamin D status and biomarkers of inflammation in runners. Open Access Journal of Sports Medicine. 2012:3 35–42
7. Close GL, Russell J, Cobley JN, Owens DJ, Wilson G, Gregson W, Fraser WD & Morton JP (2013). Assessment of Vitamin D concentration in non-supplemented professional athletes and healthy adults during the winter months in the UK: Implications for skeletal muscle function. Journal of Sports Science. 31(4):344-53
8. Cannell JJ, Hollis BW, Sorenson MB, Taft TN & Anderson JJ (2009). Athletic Performance and Vitamin D. Medicine & Science in Sports & Exercise. 41(5):1102-10
9. Ward KA, Das G, Berry JL, Roberts SA, Rawler R, Adams JE & Mughal Z (2009). Vitamin D status and muscle function in post-menarchal adolescent girls. Journal of Clinical Endocrinology and Metabolism. 94 (2): 559
10. Grimaldi AS, Parker BA, Capizzi JA, Clarkson PM, Pescatello LS, White MC & Thompson PD (2013). 25(OH) vitamin D is associated with greater muscle strength in healthy men and women. Med Sci Sports Exerc. 45(1):157-62
11. Close GL, Russell J, Cobley JN, Owens DJ, Wilson G, Gregson W, Fraser WD & Morton JP (2013). Assessment of vitamin D concentration in non-supplemented professional athletes and healthy adults during the winter months in the UK: implications for skeletal muscle function. J Sports Sci. 31(4):344-53
12. Grimaldi AS, Parker BA, Capizzi JA, Clarkson PM, Pescatello LS, White MC & Thompson PD (2013). 25(OH) vitamin D is associated with greater muscle strength in healthy men and women. Med Sci Sports Exerc. 45(1):157-62
13. N Pollock, P Dijkstra, R Chakraverty & B Hamilton (2012). Low 25(OH) vitamin D concentrations in international UK track and field athletes. South African Journal of Sports Medicine. 24(2)