Vitamin D revisited

One of the beautiful things about science is that it does not stand still, we are always learning, assessing, evaluating and discovering new things even about ‘stuff’ that’s been around for a long time. Vitamin D is something that falls into this category and the more we understand about the wide range of functions Vitamin D performs, the more obvious it becomes that we need to ensure that we get enough of this very important vitamin in our lives.


Most people can tell you that we ‘get’ vitamin D from sunlight and that it plays a role in maintaining healthy bones and teeth… but there is far more to Vitamin D than meets the eye. Despite the fact we can create Vitamin D with the need for only sunlight, Vitamin D supplementation is something CSN feel a vast majority of people, no matter how healthy their diet is, would benefit from. Especially in the cold dark winter months when we are lacking in glorious vitamin D producing sunlight.


Vitamin D Synthesis…

In non-supplemental form vitamin D synthesis is triggered by ultra-violet rays causing cholesterol, in a form called 7-dehydrocholesterol (7-DC), to convert to vitamin D3 (cholecalciferol). It is vitamin D3 that is the best form in which we can take vitamin D supplementation, as it cuts out our cholesterol middle man and eliminates the reliance on UV rays to trigger the creation vitamin D3.


Once we have vitamin D3, either from our conversion of 7-DC using sunlight or directly from our D3 supplements, this is then shipped off to the liver and kidneys to finally be converted in the body into the active vitamin D compound, calcitriol, which plays its roles in many important functions in the body.


Vitamin D roles in the body...

Vitamin D is a fat soluble vitamin; hence it is also found in oily fish, dairy products, meat and eggs. However, the amounts present in these foods are relatively small, so supplementation is often still required. As it is a fat soluble hormone it enters the cells of the body and directly influences the cell nucleus, instructing it to create new proteins from our DNA.


This is what our DNA ‘does’ within the cells. It holds the codes to put together new proteins from amino acids under the influence of specific signals, such as from hormones and in this case, vitamin D. These proteins create enzymes, which play essential roles in the body in allowing and regulating all manner of metabolic processes. It should come as no surprise then, that vitamin D availability has a profound effect on many of the body’s systems.


Vitamin D plays essential roles in the immune system and antimicrobial response, calcium regulation and bone health, cognitive function, tissue remodelling (including muscle), muscle function and growth, steroid (testosterone and oestrogen) hormone formation and the body’s response to hormonal signalling.



Vitamin D3 supplementation is given in both international units (IU) and micrograms (mcg also written as μg) depending on manufacturer, with 2000IU of vitamin D3 being the equivalent of 50mcg. Supplemental forms of D3 come in different IU/mcg amounts per tablet, but most quality, high strength formulations come with around 2000-3000IUor 50-75mcg per capsule.


It has been suggested that the current recommended daily allowance of 800IU of vitamin D3 per day is actually much too low for adults and 2000IU would be much more suitable to cover most of the populations’ requirements.


When using vitamin D supplements it is beneficial to take it with food, particularly fats, as this can help with absorption. Fish oil supplements also often contain vitamin D3, so this is a good way to ensure you get the most benefit from vitamin D supplementation with the added bonus of added omega 3’s, which is another supplement we are big fans of for many reasons beyond the scope of this article.


In summary

Vitamin D is something that we should seriously consider supplementing with, especially in climates where we get a lack of sunlight. In the UK this would be from around October right through to April. However considering the benefits that vitamin D has and the potential for missing out on its benefits, year round supplementation with vitamin D3 is something to seriously consider for its potential health, well-being and performance boosting benefits especially for those who work night shifts or work in an environment without much direct sunlight.