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How do you get enough Vitamin D to be healthy?

My work as a chiropractor in Canberra puts me in front of people every day with back aches, headaches, and all sorts of maladies. Over the years I’ve seen some people with diffuse, hard to localize pain that seemed slower to respond to manual therapy. I now wonder, with access to recent research on the effects of vitamin D deficiency, if some of their symptoms may have been due to this modern epidemic.

In my last two articles, I have discussed the recent research shedding new light (pardon the pun) on the dangers of sun exposure versus those of non-exposure. I also discussed the role of vitamin D in so many areas of our health, in addition to the great array of symptoms and disease associated with its deficiency.

In this article, I would like to discuss how you can best become sufficient (the opposite of deficient) in Vitamin D to help you regain or maintain excellent health. I might add at this point, that health, like disease, is multifactorial. Too often in the media we are exposed to the idea of a ‘super food’, nutrient or supplement that promises to cure or ward off all ills. Beware of such pronouncements. My opinion on Vitamin D is that sufficiency in this vitamin is one important piece of the puzzle that makes up a healthy lifestyle.

So how do you get enough vitamin D to be healthy?

The short answer is – sunlight! For most people, solar UVB radiation is potentially their main natural source of Vitamin D3. Your body is designed to get the vitamin D it needs by producing it when your bare skin is exposed to sunlight. The sun’s energy turns a chemical in your skin into vitamin D3, which is carried to your liver and then to your kidneys to transform it to active vitamin D. Large quantities of vitamin D are produced by your skin when you expose large areas of your body to the summer sun. In fact, your body can produce 10,000 to 25,000 IU (international units) of vitamin D in just a little under the time it takes for your skin to turn pink. Fifteen minutes per day of sun exposure on bare arms and legs without sunscreen will generally produce enough vitamin D.

So if it is this simple, why is there a modern epidemic of vitamin D deficiency, especially in developed countries?

A number of factors can play a role. Limited exposure to sunlight is the greatest factor. Except during the short summer months, people who live at latitudes below 37 degrees south of the equator in our Southern hemisphere don’t get enough UVB energy from the sun to make all the vitamin D they need. We are somewhat fortunate here in Canberra, with latitude of approximately 35 degrees south of the equator. However, this still leaves time between late May and August when our skin won’t be able to make much vitamin D from sun exposure. A good rule of thumb is that if your shadow is longer than you are tall, you won’t produce much vitamin D from the sun.

The other major factors are the use of sunscreens and clothing.

Using SPF15 sunscreen can reduce vitamin D production in the skin by up to 99%. Lastly, in our modern world, most of us spend vast amounts of our day indoors, and when we venture out into the sun, we are fully clothed.

There are other factors that also contribute to how much vitamin D your skin can make.

People with darker skin and older age will make less vitamin D from the same amount of sun. Also, glass blocks all UVB rays, so being in the sun behind glass will make you warm, but your skin will not produce any vitamin D. So, clearly, for large parts of the year, sunshine will not deliver the vitamin D you require to be healthy.

What about dietary sources?

Foods such as oily fish (cod, salmon, tuna), egg yolks, beef liver (yum!) all contain vitamin D naturally. Also, milk, orange juice and cereals are often fortified (have nutrients added) with vitamin D. All of these foods, however, only contain relatively small amounts of vitamin D. you would have to consume around 2.5kg of tuna, or 100 egg yolks to reach sufficiency.

Taking vitamin supplements would seem necessary for most people to reach sufficient levels of vitamin D for good health.

How much to supplement with? Opinions vary widely in the literature (from approximately 600 – 5000 IU per day), and historically, there have been concerns regarding overdosing with vitamin D. Since it is fat-soluble, vitamin D can be stored in the body, and can potentially build up to dangerous levels. However, according to Dr. Robert Heaney (Heaney et al. 2003 Human serum 25 hydroxycholecalciferol response to extended oral dosing with cholecalciferol. Am. J Clin. Nutr. 77: 204-210), humans utilize approximately 4000 IUs of vitamin D per day.

The Executive Director of the Vitamin D council (USA), Dr. John Cannell MD, states ( that there is no evidence anywhere in the published literature that even 10,000 IUs of vitamin D per day is toxic to humans and that human toxicity is not likely to occur until over 40,000 IUs of daily consumption. It would be prudent to choose somewhere in the mid-range – for adults, 2000 IU per day supplementation would be considered both safe and effective in providing sufficient Vitamin D for good health.

Clearly, the answer, as with most things related to health, is a combination approach. Regular short doses of sunshine where possible (but using sunscreen and clothing to protect especially those areas prone to regular sun exposure); diet including oily fish; and supplementation of 2000 IU per day for an adult will give you enough Vitamin D to help maintain excellent health.