Sport

Vitamin D in Footballers

Vitamin D supports bone, muscle and immune function. This article reviews deficiency risk in footballers, winter supplementation and individualized monitoring.

Date 19.08.2020

Author

maq

Topics

Vitamin D is an organic compound present in food but we can meet our requirements through exposure to the sun.

The serum concentration of 25(OH)D (blood vitamin D) is the best parameter to determine our vitamin D levels, but these levels are also influenced by other parameters such as parathyroid hormone (PTH) and blood concentrations of calcium and phosphorus. (1)

It is well known throughout the world that an adequate level of vitamin D is necessary to maintain proper bone and skeletal health.

In recent years it has been discovered that it has other roles of great importance on the immune system, inflammation, and sports performance (2).

Therefore, its deficiency can lead to more pathological complications not only of an osteoarticular nature, but also cardiometabolic, inflammatory, etc. (3).

Among its functions:

Acts as a switch for gene expression: An adequate concentration of vitamin D in the blood is necessary to optimize genomic function (4). This makes it important for health, training, and performance
It improves the expression of genes related to calcium metabolism, which is then related to bone mineral density (BMD). This is very important for the prevention of bone injuries in athletic populations, such as in this case, football players.
They can influence, at the skeletal muscle level, the expression of genes involved in muscle growth and the differentiation of fast fibers (5; 6). Other research, with more limited evidence, has seen that it could directly harm muscle strength.
Other functions recognized in recent years have to do with the immune system.
It may be related to innate immunity in the respiratory tract, responsible for the secretion of monocytes, macrophages, and epithelial cells in that area. In addition, it improves susceptibility to a depression of innate immunity due to prolonged intense training.
Regarding inflammation, it could help control it through the production of anti-inflammatory cytokines.
In athletes, the prevalence of deficiency and insufficiency varies depending on the season, training location, sport, and skin color (1).
In professional footballers, vitamin D deficiencies have also been observed during the winter months (7; 8) since there is not good ultraviolet radiation with an adequate wavelength.

Therefore, vitamin D supplementation3 is usually used during these months.

A dose of 5000 IU appears to be safe and adequate to restore 25 [OH] D levels in 6 weeks (8).

In this way, the recommendations, so that adaptations to training occur correctly, are to establish supplementation that corrects possible deficiencies during this winter period, when sun exposure is lower (9).

It should be taken into account that vitamin D is a fat-soluble vitamin, and therefore accumulates in the body, so possible toxicity should be considered in those people who have high baseline levels and are supplemented with high doses.

And why isn't nutrition enough?

Vitamin D is found in few foods. Both in foods of animal origin (D3) and of plant origin (D2) it has an absorption of around 50% (bioavailability) when combined with other fats in the diet. Therefore, its absorption improves with meals higher in fat (10) and it may be limited in those diets lower in fat or when there is intestinal malabsorption. All of this suggests that supplementation with this vitamin should be considered to raise low blood levels.

Supplementation with 5000 IU appears safe and effective for restoring 25 [OH] D levels, especially during winter periods. Even so, the principle of individualization should prevail, that is, each case should be studied by the team's medical staff, in order to act in the best possible way with each footballer (9).

BIBLIOGRAPHY

Larson-Meyer, D.E. (2010). The importance of vitamin D in athletes. Sports Science Exchange (2015) Vol. 28, No. 148, 1-6
Larson-Meyer, D.E., and K.S. Willis (2010). Vitamin D and athletes. Curr. Sports Med. Rep. 9:220-226.
Holick, M.F. (2007). Vitamin D deficiency. N. Engl. J. Med. 357:266-281.
Hossein-nezhad, A., and M.F. Holick (2013). Vitamin D for health: a global perspective. Mayo Clin. Proc. 88:720-755.
Barker, T., T.B. Martins, H.R. Hill, C.R. Kjeldsberg, R.H. Trawick, L.K. Weaver, and M.G. Traber (2011). Low Vitamin D impairs strength recovery after anterior cruciate ligament surgery. JEBCAM 16:201-209.
Girgis, C.M., R.J. Clifton-Bligh, M.W. Hamrick, M.F. Holick, and J.E. Gunton (2013). The roles of vitamin D in skeletal muscle: form, function, and metabolism. Endocrin. Rev. 34:33-83.
Morton, J.P., Iqbal, Z., Burgess, D., Drust, B., Close, G.L. and Brukner, P.D. (2012). Seasonal variation in vitamin D status of professional soccer players of the English Premier League. Physiol. Nutr. Metab. 37: 798-802.
Close, G.L., J.Russell, J.N.Cobley, D.J.Owens, G.Wilson, W.Gregson, W.D.Fraser and J.P.Morton (2013a). 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. Sports. Sci 31: 344-353.
Morton, J.P. (2014). Supplements for Consideration in Football. Sport Science Exchange 27 (130): 1-8
Raimundo, F.V., G.A. Faulhaber, P.K. Menegatti, S. Marques Lda, and T.W. Furlanetto (2011). Effect of high- versus low-fat meal on serum 25-hydroxyvitamin D levels after a single oral dose of vitamin D: A single-blind, parallel, randomized trial. Int. J. Endocrinol. 809069.