Football Super Bowl, Bones & Muscle, and Vitamin D
It goes without saying that vitamin D levels, measured as 25(OH)D3 in blood, decline during winter months. Because vitamin D is essential to maintain strong bones and muscles, Galan and colleagues wanted to know the circulating 25(OH)D concentrations required in the fall to maintain vitamin D sufficiency in professional football players during winter. As expected, vitamin D status was affected by sun exposure (# of cloudy/rainy days, hours in the sunshine, UV index, and skin exposure) as well as skin color.
With Super Bowl 50 approaching, it is not surprising to see The Wall Street Journal article “Elite Athletes Try a New Training Tactic: More Vitamin D” written by Rachel Bachman (@Bachscore) and accompanying video “Can Vitamin D Deficiency Result in Athlete Injuries?” These segments reflect data collected on NFL injury reports between 2011-12 and 1012-13 seasons.
Maroon and colleagues reported significantly lower vitamin D concentrations in players having 1 bone fracture (vs no fractures); after adjusting for number of professional years played. Black professional football players had lower 25(OH)D concentrations than white players, potentially increasing their risk of injury. While most of us will not be playing in Superbowl 50, vitamin D status is still important for virtual athletes!
Increasing vitamin D intake elevates serum 25(OH)D concentrations in a predictable manner in Caucasians and African-Americans although there is tremendous variability in individual response. Why this variability? Because polymorphisms in genes regulating vitamin D metabolism affect serum 25(OH)D levels. People differ in appearance and genetics, even within a family.
Genetic polymorphisms in 3 genes are associated with a 2-fold difference in risk of vitamin D deficiency. While studies examining associations are valuable because they generate hypothesis, a study does not change guidance. Especially when the authors write “no association was found between the plasma 25(OH)D concentrations and breast cancer risk (P > 0.06 with and without multiple-testing adjustment)”. So what should we do?
- At minimum, take a daily supplement providing the Recommended Dietary Allowance (RDA) for your age and sex.
- Personalize nutrition guidance by having your serum 25(OH)D measured. Because maintaining serum 25(OH)D concentrations >120 nmol/L may have adverse effects on muscle function and bone structure, monitor serum 25(OH)D levels annually (preferably during the winter).
- Adjust your vitamin D intake so your body maintains vitamin D sufficiency. As the Institute of Medicine advises, keep serum 25(OH)D concentrations between 50-125 nmol/L.
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Galan F, Ribas J, Sanchez-Martinez PM, Calero T, Barco Sanchez A, Munoz A. Serum 25-hydroxyvitamin D in early autumn to ensure vitamin D sufficiency in professional football players. 2012 Clin Nutr doi: 10.1016/j.clnu.2011.07.008
Maroon JC, Mathyssek CM, Bost JW, Amos A, Winkelman R, Yates AP, Duca MA, Norwig JA. Vitamin D profile in National Football League Players. 2015 Am J Sports Med doi: 10.1177/0363546514567297
Gallagher JC, Sai A, Templin II T, Smith L. Dose response to vitamin D supplementation in postmenopausal women: A randomized trial. 2012 Ann Intern Med doi: 10.7326/0003-4819-156-6-201203200-0005
Gallagher JC, Peacock M, Yalamanchili V, Smith LM. Effects of vitamin D supplementation in older African American women. J Clin Endocrinol Metab doi: 10.1210/jc.2012-3106
Wang TJ, Zhang F, Richards JB, Kestenbaum B, van Meurs JB, Berry D, Kiel DP, Streeten EA, Ohlsson C, Koller DL, Peltonen L, Cooper JD, O’Reilly PF, Houston DK, Glazer NL, Vandeput L, Peacock M, Shi J. Common genetic determinants of vitamin D sufficiency: a genome-wide association study. 2010 Lancet doi: 10.1016/S0140-6736(10)60588-0
Bischoff-Ferrari HA, Dawson-Hughes B, Orav J, Staehelin HB, Meyer OW, Theiler R, Dick W, Willett WC, Egli A. Monthly high-dose vitamin D treatment for the prevention of functional decline: A randomized clinical trial. 2016 JAMA Intern Med doi: 10.1001/jamainternmed.2015.7148