We've all heard about vitamin D, the miraculous, naturally-occurring vitamin processed in our skin through exposure to sunlight. However, according to recent studies, as many as thirty percent of Australians suffer from a mild, moderate or severe vitamin D deficiency.

So, why does this matter? Vitamin D has been linked to bone health, muscle weakness and joint pain.

What is Vitamin D and how does it affect the human body?
What we refer to as ‘vitamin D' is actually a collection of fat-soluble secosteroids that assist the human body in a variety ways. As colloidal minerals and other vitamins are essential for body-health, vitamin D secosteroids help the body retain and absorb these important chemical additions. Calcium, iron, phosphate, zinc and magnesium are processed and absorbed more easily thanks to vitamin D, which is activated in the liver and kidney.

Essentially, the vitamin is formed on the surface of the skin during direct exposure to sunlight. Ultra Violet B (UVB) radiation from the sun is predominantly responsible for the internal production of vitamin D, although small amounts can also found in foods such as oily fish, eggs, and 'vitamin D-fortified' products (these are more common overseas).

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Vitamin D helps maintain healthy bones and teeth, supports lung function and cardiovascular health (Photo: Vitamin D Council/Facebook)

Doctors and other health based organisations (such as the Cancer Council Australia and Osteoporosis Australia) suggest vitamin D is essential to maintaining stronger bone density and muscle growth. The vitamin aids in the absorption of calcium from food, transferring the positive benefits to nearby bones and muscles.

In addition to this benefit, vitamin D is also an essential part of regulating and processing calcium within the bloodstream; when the processed calcium is pumped through the body's arteries and muscles, the end result is increased muscle strength and promoted growth.

Who is particularly at-risk of developing a deficiency?
Though many of us are not able to get enough vitamin D, some people are considered more susceptible to a deficiency. In short, the young and the old are more prone to developing a vitamin D deficiency, and its effects can be disastrous.

In children, a shortage of vitamin D can lead to rickets (a painful illness that results in bone deformities and poor muscle development) and abnormal bone growth patterns.

In older people, a deficiency can also lead to issues with bone density and muscle strength, a deficiency that can increase your risk of falling and developing painful bone fractures. For those of us over the age of seventy, some health experts suggest vitamin D can be carefully managed by increasing direct exposure to sunlight or taking supplements.

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Up to 50% of adults and children worldwide are vitamin D deficient according to recent studies (Photo: Vitamin D Day/Facebook)

Guidelines and recommended levels of exposure to sunlight
According to the Cancer Council of Australia, there are a series of important factors associated with the healthy development of vitamin D through direct exposure to sunlight. But they warn there are also several risks – such as skin cancer – associated with prolonged and unprotected exposure to the sun.

The most important unique factors are: the general UV level of your location, your skin type (fair skin or dark skin) and other lifestyle choices. As Australia is such a diverse nation, the UV levels vary drastically across different states and times.

Accordingly, the recommended amount of time will vary from place to place. The Cancer Council suggests Australians vary their exposure to sunlight in the summer and winter seasons.

During the summer season, all Aussies should seek to be exposed for no more than a few minutes per day. But during the winter (everywhere except Brisbane and Darwin, where the 'few minutes a day' rule is permanent), the length of exposure should be increased to about two to three hours per week.

Those with naturally dark skin should increase the length of exposure, but a medical opinion is needed before any drastic changes are implemented. Studies reveal prolonged exposure does not 'boost' your vitamin D levels or result in a store of the secosteroids within the body; instead, many recommend short, incidental exposure on a daily basis.

Importantly, the amount of skin exposed can also be a determining factor in the recommended length of exposure. The 'few minutes rule' applies to the normal exposure of areas including the face, the arms and the hands. But if more of your skin is exposed, then the required, healthy amount should be reduced.

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Oily fish, tofu, mushrooms, caviar, cod liver oil and egg are some types of foods rich in Vitamin D

The use of vitamin D pills
If you are concerned about your vitamin D levels, seek a professional medical opinion. Your doctor may administer a simple blood test that will reveal your stored levels of vitamin D, especially if your personal risk factors are elevated.

Osteoporosis Australia note that a vitamin D level of 50 nmol/L at the end of winter, and 60-70 nmol/L during summer, represents a normal and healthy amount. In cases where a deficiency is recorded (and where your personal circumstances call for it), your doctor may recommend a supplement be taken.

These supplements can take the form of drops or liquid injections, though tablets and capsules are more common these days.

For specific advice on the amount required, consult your doctor and heed his or her opinion; as a rule of thumb, pharmacists can only provide general advice about vitamin D supplements.

Normally, a vitamin D supplement regime will take about three to five months to register positive results.

In many cases supplements have been found to be medically necessary; but for most people, regular and safe exposure to sunlight is still the best way to maintain your vitamin D levels.

What do you think about those of us living in sunny states such as Queensland being diagnosed with vitamin D deficiency? Join the conversation.