Sports health benefits of vitamin d

Abstract

Context: Vitamin D is a potent secosteroid hormone that provides many skeletal and extraskeletal health benefits. Musculoskeletal injury prevention and recovery are potentially affected by sufficient circulating levels of the storage form of vitamin D: 25-hydroxyvitamin D3, or 25(OH)D. Vitamin D deficiency can exist among young, active, and healthy people, which may put them at increased risk for injury and prolonged recovery.

Evidence aquisition: PubMed was searched using vitamin D and skeletal muscle, vitamin D and athletic performance, and vitamin D review articles. Studies from the 1930s to 2012 were used for the review.

Results: There is strong correlation between vitamin D sufficiency and optimal muscle function. Increasing levels of vitamin D reduce inflammation, pain, and myopathy while increasing muscle protein synthesis, ATP concentration, strength, jump height, jump velocity, jump power, exercise capacity, and physical performance. 25(OH)D levels above 40 ng/mL are required for fracture prevention, including stress fractures. Optimal musculoskeletal benefits occur at 25(OH)D levels above the current definition of sufficiency (> 30 ng/mL) with no reported sports health benefits above 50 ng/mL.

Conclusions: Vitamin D deficiency is common in athletes. For athletes presenting with stress fractures, musculoskeletal pain, and frequent illness, one should have a heightened awareness of the additional likely diagnosis of vitamin D deficiency. Correction of this deficiency is completed by standardized and supervised oral supplementation protocols producing significant musculoskeletal sports health benefits.

Keywords: 25-hydroxyvitamin D; musculoskeletal; vitamin D; vitamin D deficiency; vitamin D supplementation.

Figure 1.

Production of active vitamin D₃. The storage form of vitamin D, calcidiol, or 25(OH)D (black box) is made following liver hydroxylation of vitamin D₃ following dietary ingestion or skin synthesis from ultraviolet B exposure (peak skin production follows a 5- to 10-minute exposure of summertime sun between 10 am and 3 pm [produces about 10 000 IU of vitamin D₃]). Active vitamin D produced either locally or through the kidney endocrine pathway has its biological effect by altering gene expression through a specific vitamin D response element.

Figure 2.

Diagram of sports health benefits of vitamin D. An increase in the storage form of vitamin D is associated with incremental improved musculoskeletal performance. Maximum benefit is achieved in those who are vitamin D deficient (< 30 ng/mL, shaded box). At present, there does not appear to be any added sports health benefit to increasing vitamin D stores above 50 ng/mL.

Figure 3.

Benefits are concentration dependent. Rickets is easily corrected/prevented with low levels of 25(OH)D. Emerging research indicates that additional sports health benefits require higher concentrations of 25(OH)D than 30 ng/mL, defined as sufficiency (shaded column). These higher levels can be achieved with appropriate supplementation protocols.

Figure 4.

National Academy of Sciences upper limits. “Upper intake levels represent the upper safe boundary and should not be misunderstood as amounts people need or should strive to consume.” Adapted from http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=13050.