Vitamin D: The Sunshine Vitamin

With literally mountains of new data emerging weekly on Vitamin D, it’s beginning to appear like your parents generation were on to something when they said a bit of sunshine is good for what ails you!

50 to 90% of vitamin D is produced by sunshine exposure on the skin (1) with the remaining minority coming from diet. is essential for almost everything from bone health, to hormone production, to preventing arthritis, and improving blood cholesterol!

However, despite the ample health benefits and relative ease of sourcing vitamin D (just stand out side?!) there is still a global epidemic in Vitamin D deficiencies. An estimated 1 Billion people are considered to have sub optimal vitamin D levels (1) and this is something with both health implications in the longer term but also a very easy method of correcting these issues; supplementation!

Benefits of Supplementation:

Also described as “the Sun Vitamin” Vitamin D is not actually your typical mineral, trace element or in fact, a vitamin at all!

Rather, Vit D is actually steroidal with behaviour similar to that of a hormone. It regulates the functions of over 200 genes and is essential for growth and development (2).

Benefits include:

  • Improved muscle function
  • Protection from cardiovascular disease
  • Stronger bones
  • Decreased risk of type 2 diabetes by positively impacting insulin sensitivity
  • Decreased risk of certain cancers




Sources of Vitamin D

As per the findings of Naeem (2010) “Exposure to sunshine each day helps human body to manufacture the (majority of the) required amount of vitamin D. However, due to fear of developing skin cancer most people avoid the sun exposure. To prevent vitamin D deficiency, one should spend 15 to 20 minutes daily in the sunshine with 40% of the skin surface exposed. High concentration of melanin in the skin slows the production of vitamin D; similarly aging greatly reduces skin production of vitamin D. Use of sunblock, common window glass in homes or cars and clothing, all effectively block UVB radiation – even in the summer. People who work indoors, wear extensive clothing, regularly use sunblock, are dark skinned, obese, aged or consciously avoid the sun, are at risk of vitamin D deficiency.” (1)

Therefore, sources of Vitamin D include spending 15-20 minutes in the sun with decent skin exposure, or introducing dietary sources of Vit D. These include fatty and oily fish, beef liver and organ meats, Egg yolks, fortified dairy products and cheese. Of course the more free range, grass fed and/or organic sources of these foods will be higher in naturally occurring Vitamin D and so should be the preferred sources. However, if these are not foods regularly seen in your diet, you can happily purchase a high quality Vit D supplement.

So let’s say you work in doors, you are not able to add significant amounts of dietary sources of Vitamin D in to your diet, and you are left with taking a Vit D supplement as your only source. So how much should you take is the next most logical question right?

Well let’s take a look!


300-600iU per day are currently the American Health Organisation’s recommendations as well as the Australian RDA presently. However, this was set pre 1997, after which a lot of the health benefits of higher doses of vitamin D supplementation were explored (3).

In light of more recent data, doses from 2000-5000iU per day have been studied with great benefits and no conceived risks or adverse side effects. In the bodybuilding community, even higher dosed periods of mega dosing have also been implemented, with intakes of 5000-10,000 iU per day recorded with some regularity.

For the average trainee attempting to optimise health and correct any underlying deficiencies, a dosage of around 2000-3000iU will be ample for the initial 2-4 weeks and will see marked improvements in blood serum concentrations if there were any underlying deficiencies. A regular dosage is largely up to the individual of course but at least we now have the ranges to work within to make an informed decision on what will work best for you.

Take home:

There are a host of health benefits, crucial body functions and even lifestyle diseases that increasing your intake of Vitamin D will bring with it and even help prevent! So as a take home I think we can all agree that increasing your intake of the sunshine vitamin is in your best health interests and when it comes to increasing anything in the body, a variety of sources is always best. So start adding in both supplemental Vit D, dietary sources of Vit D and finally go for a walk outdoors for 15-20 mins a day, and see if your body doesn’t thank you for it! 


  1. Naeem Z. Vitamin D Deficiency- An Ignored Epidemic. International Journal of Health Sciences. 2010;4(1):V-VI.
  2. The role of vitamin D for bone health and fracture prevention. Holick MF.Curr Osteoporos Rep. 2006 Sep; 4(3):96-102.
  3. “Benefits and Requirements of Vitamin D for Optimum Health: A Review”, Alternative Medicine Review, Vol 10, No. 2, 2005, Grant, W. And Follick, M.F.