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Vitamin D: Fact vs. Fiction

30 August 2013 Andrew Verdon

Sun Smart is always a good idea.

"Sun Smart is always a good idea."

Photo by:
Kylie Wilson,

Recently, vitamin D has been receiving received more and more attention regarding how it impacts overall health and that it may be useful in prevention of certain conditions, as well as improving performance. A wide range of purported benefits, indeed!

Too good to be true? Well, let's look at Vitamin D in depth, keeping in mind that the body can obtain it via just the two sources: food and sunlight.

We have always known the link between vitamin D and bone health in females. However, the mainstream media is now picking up a lot of recently published studies, along with an increasingly common trend to believe that insufficient vitamin D in modern sun-phobic societies is behind a whole range of chronic diseases. The media then further notes that the current recommended intakes are far below the levels some experts believe are actually necessary:

So what does Vitamin D do for us?
Vitamin D is related to health through the following processes:

  • Bone health
  • Immunity
  • Inflammation system regulation
  • Muscle function
  • Cell Growth

Low levels of vitamin D may lead to various conditions that include:

  • An elevated risk of developing (and dying from) cancers of the colon, breast and prostate
  • High blood pressure and cardiovascular disease
  • Osteoarthritis
  • Rheumatoid arthritis
  • Immune-system abnormalities that may result in disorders like multiple sclerosis
  • Type 1 diabetes

The two sources of Vitamin D.

1. Food
The goal is to acquire a part of your daily Vitamin D requitement from your food. The best choices include: :

  • Wild-caught oily fish (e.g., mackerel, salmon, sardines, tuna) :
  • Fortified milk, fortified orange juice
  • Egg yolks
  • Certain cereals

2. Sunlight
Vitamin D conversion comes mainly from sunlight and happens around midday, when the sun is at its highest. Specifically, it is derived from the ultraviolet-B rays, which are absorbed through the skin. This is your body's main source of this nutrient. In Winter especially, many people are out in the morning or evening in low light levels, but not as much during the middle of the day. People in the modern world have lifestyles that may impact on them acquiring the necessary levels of Vitamin D that evolution intended us to have.

Also, depending on the region you live in, Vitamin D conversion during the Winter months may be severely limited (e.g., latitudes above or below 35-37 degrees North or South have no conversion). Early humans evolved near the equator, where sun exposure is intense all year round, and minimally clothed people spent most of the day outdoors. Here it was easy for the human body to make enough Vitamin D from its skin to meet its needs, no matter what time of year it was.

So just how much sun is actually needed?
Anywhere from 5 to 30 minutes per day of sun exposure is suggested. However, this depends on various factors.

The lighter the skin colour one has, the less time is needed in the sun to absorb Vitamin D. Conversely, the darker the skin colour one has, the longer the exposure time for optimal conversion to occur. Note well, however, the less sun exposure, combined with the darker a person's skin and/or the more sunscreen used, the less Vitamin D is formed.

In looking for a general recommendation, evidence suggests going outside in Summer, unprotected by sunscreen (except for the face, which should always be protected), wearing minimal clothing from 1000hrs to 1500hrs, two or three times a week, for 5 to 10 minutes. Note: Sunscreen with an SPF of 30 will reduce exposure to by 95 to 98 percent!

What is the recommended intake of Vitamin D?
Currently established by the Institute of Medicine and measured in International Units, the following levels apply: :

  • 200 I.U. per day for children to age 50:
  • 400 I.U. per day for adults aged 50 to 70
  • 600 I.U. per day for those older than 70

Whilst an upward revision of these amounts is in the works, studies continue to refine optimal blood levels and recommended dietary amounts, The new guidelines settle around daily levels of 400 to 1000 IU for healthy adults under age 50. For adults over 50, between 800 and 2000 IU is recommended.

So can I just pop a pill?
Vitamins are designed to consumed as part of the intake of a wide variety of good quality food sources and food choices we should be making. Granted, sometimes this is difficult to achieve sometimes in life. It is precisely in times like these, when the body or lacking something it needs, that you can supplement it.

The key word is vitamin tablets are party of the broad range of'dietary supplements'. If you have educated advice that your Vitamin D is low, and food intake or sunlight conversion will not raise it to the required level, then the medical advice will be too supplement it. Like anything else in life, though, you get what you pay for, so my advice is to buy good quality vitamins. You generally find the best quality products are available at pharmacies more so than supermarkets, especially the smaller grocery stores with limited shelf space. Always check the use by date on the container, as they may be stored for long periods before on sale. And read if it is better for the product life to store in the fridge once the seal is opened.

Overall Vitamin D Recommendations.:

  • It does not matter whether you are a female or male - this is NOT just a'Female' bone issue:
  • Seek to gain some of your vitamin D per day through your food
  • 5- 15 min of sunlight per day, depending on skin colour and locale
  • Always protect your face from sun exposure
  • Know your current Vitamin D levels, so as to better understand if you are not at optimal levels.

The potential consequences of this deficiency are likely to go far beyond inadequate bone development and excessive bone loss that can result in falls and fractures. There is plenty of evidence that Vitamin D deficiency will impair physical performance. As a result, anyone who's at all interested in being healthy, should be acutely aware of their Vitamin D needs and levels.


  • Always see a medical professional for further advice specific to yourself.
  • Continue being'Sun Smart' in the harsh Australian conditions, just be aware in Winter (Southern States) of the importance direct sunlight can have on health and wellbeing.

Andrew Verdon

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Eating well, especially out on the track is crucial.

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