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Vitamin D – What, Why & When?

Whether it is protein, vitamins, minerals, carbs, blends or preworkouts, there is a myriad of supplements you could be taking. When picking supplements, we need to choose wisely and find what is going to work and give us most bang for our buck.

At this point I’d point out vitamin D3 tablets, TPW™ have an awesome super strength capsule with 90 servings which would last 90 days. So that is a little under three months of supplementation for less than a fiver, now that is some good value. So we know that this is good value, but what can vitamin D do… and why should you be taking it?

Firstly, vitamin D contributes to many things such as bone health, protein synthesis, muscle function and regulation of skeletal muscle all of which can have an impact on our performance, despite this as many as 68% of athletes are deficient in vitamin D (5, 7, 10, 12, 17, 20). Considering that vitamin D can be obtained from our diets and ultraviolet B rays it is an amazing statistic, that being said a study was carried out in Qatar which is a very sunny place and they found that up to 93% of athletes based there were still deficient in the vitamin so the sun may not be the best place to obtain vitamin D (3, 4, 15). So we know where we can get it, what it can do for us and that most are deficient in it, lets go over some studies to back up how good of a supplement vitamin D is.

My favourite study to bring up in relation to vitamin D is this one, 13% of participants in the study were wheelchair bound due to severely low levels of vitamin D yet after three months of vitamin D supplementation they were able to walk unassisted (1). Ok, they weren’t doing back flips or running marathons, but in three months they went from wheel chair bound to walking unassisted, that is amazing and quoting from the study it was a “remarkable recovery of their muscle strength”. Magnitudes of other studies have been completed all showing the same correlation of higher vitamin D levels resulting in higher strength, power and force (2, 11, 16, 18, 19). Now for the lifters of you reading this, you should be paying attention, if you’re plateauing maybe the addition of vitamin D will give you that little bit extra to get pass where you are stuck.

Ok, so we can see why the lifters would want to be using vitamin D but what about the people who are into long distance running, crossfit, or people who vary their workouts between all aspects of plyometrics and lifting?

Well as I said before, vitamin D contributes to bone health. A lot of people care about how they look and not necessarily what is going on inside (which is concerning but I digress), bone health is important to all of us, when a runner trains they can obtain stress fractures which usually occur in the femur and the same can be said for people who participate in cross fit (although the locations will differ) and lifters do experience higher bone mass due to stress placed on the bone from hypertrophied muscle. So how does vitamin D help in this regard?

 It has been seen in various studies that a higher vitamin D level leads to less stress fractures, meaning our bones are able to withstand more before these fractures occur 8, 9, 13, 15).     In fact, one study of US navy cadets found 20% lower stress fractures occurring in their eight week boot camp if the cadet was taking vitamin D. Now, to be clear, bone will grow when a new strain is put on it but a stress fracture could leave you unable to train, so having it grow in a normal manner is ideal.

Ok, I feel I’ve driven home the point that vitamin D is good in a magnitude of different ways so now we will take a look at how much we should be taking. For the average adult the recommended daily intake is 600IU (17). So it is fantastic to see that The Protein Works super strength vitamin D comes with 5000IU, now you may be reading that thinking this is an overdose and it is not, you need to be taking a much higher amount for a long period before any nasty effects occur (5, 6, 14). Adding to this, due to our training regimes it can be argued that we require a higher dosage than normal people due to the extra metabolic stress, adding to this any extra will simply pass through your system.




1.         Al-Said, Y. A., Al-Rached, H. S., Al-Qahtani & Jan, M. M. (2009). Severe proximal myopathy with remarkable recovery after vitamin D treatment. Canadian journal of neurological sciences, 36(3), 336-339.

2.         Bischoff, H. A., Stahelin, H. B., Urscheler, N., Ehrsam, R., Vonthein, R., Perrig-Chiello, P., Tyndall, A., & Theiler, R. (1999). Muscle strength in the elderly: Its relation to vitamin Dmetabolites. Archies of physical medicine and rehabilitation, 80(1), 54-58.

3.         Hamilton, B. (2012). Vitamin D and the athlete: considerations for the practitioner. Aspeter sports medicine journal, 1(2), 96—100.

4.         Hamilton, B., Grantham, J., Racinais, S., & Chalabi, H. (2010). Vitamin D deficiency is endemic in middle eastern sportsmen. Public health nutrition, 13(10), 1528-1534.

5.         Jeukendrup, A., & Gleeson, M. (2010). Sport nutrition: an introduction to energy production and performance (2nd ed.). United States of America: Human Kinetics

6.         Jones, G. (2008). Pharmacokinetics of vitamin D toxicity. The American journal of clinical nutrition, 88(2), 528S-586S.

7.         Lanham-New, S. A., Stear, S. J., Sherriffs, S. M., & Collins, A. L. (2011). Sport and exercise nutrition (1st ed.). United Kingdom: Wiley-Blackwell

8.         Lappe, J., Cullen, D., Haynatzki, G., Recker, R., Ahlf, R., & Thompson, K. (2008). Calcium and vitamin D supplementation decreases incidence of stress fractures in female navy recruits. Journal of bone and mineral research, 23(5), 741-749.

9.         Lehtonen-Veromaa, M. K., Mottonen, T. T., Nuotio, I. O., Irjala, K. M., Leino, A. E., & Viikari, J. S. (2002). Vitamin D and attainment of peak bone mass among peripubertal finnish girls: a 3-y prospective study. The American journal of clinical nutrition, 76(6), 1446-1453.

10.   Marieb, E. N., & Hoehn, K. N. (2014). Human anatomy & Physiology (9th ed.). United Kingdom: Pearson

11.   Mowe, M., Haug, E., & Bohmer, T. (1999). Low serum calcidiol concentration in older adults with reduced muscular function. Journal of the American geriatrics society, 47(2), 220-226.

12.   Ogan, D., & Pritchett, K. (2013). Vitamin D and the athlete: Risks, recommendations, and benefits. Nutrients, 5(6), 1856-1868.

13.   Outila, T. A., Karkkainen, M. U., & Lamberg-Allardt, C. J. (2001). Vitamin D status affects serum parathyroid hormone concentrations during winter in female adolescents: associations with forearm bone mineral density. The American journal of clinical nutrition, 74(2), 206-210.

14.   Ozkan, B., Hatun, S., & Bereket, A. (2012). Vitamin D intoxication. The Turkish journal of pediatrics, 54, 93-98.

15.   Parsons, T. J., Dusseldorp, M. V., Vliet, M. V., Werken, K. V., Schaafsma, G., & Staveren, W. A. (1997). Reduced bone mass in dutch adolescents fed a macrobiotic diet in early life. Journal of bone and mineral research, 12(9), 1486-1494.

16.   Powers, S., Nelson, B. W., & Larson-Meyer, E. (2011). Antioxidant and vitamin D supplements for athletes: Sense of nonsense?. Journal of sport sciences, 29(sup 1), s47-s55.

17.   Thompson, J., Manore, M., & Vaughan, L. (2014). The science of nutrition (3rd ed.). United Kingdom: Pearson

18.   Verhaar, H. J., Samson, M. M., Jansen, P., Vreede, P. L., Manten, J. W., & Duursma, S. A. (2000). Muscle strength, functional mobility and vitamin D in older women. Aging clinical and experimental research, 12(6), 455-460.

19.   Ward, K. A., Das, G., Berry, J. L., Roberts, S. A., Rawer, R., Adams, J. E., & Mughal, Z. (2009). Vitamin D status in muscle function in post-menarchal adolescent girls, The journal of clinical endocrinology & metabolism, 94(2), 559-563.

20.   Willis, K. S., Peterson, N. J., & Larson-Meyer, D. E. (2008). Should we be concerned about the vitamin D status of athletes?. International journal of sport nutrition and exercise metabolism, 18(2), 204-224.

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