Vitamin D lower in NFL players with muscle injuries

Lack of vitamin D may increase the chance of muscle injuries in athletes — especially football players, according to a study presented at the 2011 Annual Meeting of the American Orthopaedic Society for Sports Medicine in San Diego.

“Vitamin D has many roles,” Michael Shindle, MD, said. “It has been shown to play a role in calcium homeostasis, muscle health and bone health … there is controversy whether peak athletic performance may occur when vitamin D levels are 50 ng/mL or higher. We wanted to look at the prevalence of vitamin D in athletes.”

Shindle and his team tested the vitamin D levels of 89 professional football players from a single NFL team in the spring of 2010. Mean age of the players was 25 years old. The research team requested data from the football team to help determine the number of players who had lost playing time due to muscle injuries.

According to the study results, the researchers found deficient total vitamin D levels in 27 (30.3%) of the players examined. Forty-five players (50.6%) displayed vitamin D levels consistent with insufficiency, while the remaining 17 players displayed vitamin D values described as within normal limits.

“There was an alarming percentage — 80.9% of players — with abnormal levels,” Shindle said. “No players had a vitamin D level greater than 50.”

Mean vitamin D levels in black players were found to be significantly lower than those found in white players, the researchers reported — 20.4 ng/mL to 30.3 ng/mL, respectively. The 73 players who had no reported muscle injury were found to have a mean vitamin D level of 24.7 ng/mL, while 16 players with a muscle injury displayed a mean vitamin D level of 19.9 ng/mL.

“It is still unknown what is the right amount [of vitamin D] for optimal performance,” Shindle concluded. “Further studies are warranted to see if there is a correlation with strength and performance testing.”

Reference:

Shindle MK, Voos JE, Gulotta L, et al. Vitamin D status in a professional American football team. Paper #46. Presented at the 2011 Annual Meeting of the American Orthopaedic Society for Sports Medicine. July 7-10. San Diego.

Disclosure: The authors have no relevant financial disclosures.

The investigators in this interesting study looked at one variable in a study of muscle injuries in players on a single NFL football team. What is interesting is the prevalence of insufficient or deficient vitamin D levels in the football players who had lost playing time due to muscle injuries and the difference in injury rates between black and white players.

Before we can assume, however, that vitamin D deficiency leads to muscle injuries more needs to be known such as the positions of the players who were injured, the rate of muscle injury in players with normal vitamin D levels, and if the muscle injuries in the 16 players were normal for that team.

The question posed by the study’s investigators remains: what is the right level of vitamin D for optimum performance? This study dealt only with a lab finding in muscle injuries in NFL players. Further studies are warranted to follow up on this interesting concept of the association between vitamin D and peak performance and muscle injuries in athletes.

— Champ L. Baker, Jr.
Orthopedics Today Editorial Board member

Disclosure: Dr. Baker has no relevant financial disclosures.

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