It’s Vitamin D Day this November 2nd
Vitamin D deficiency is a worldwide problem affecting people of all ages. Across the globe, vitamin D deficiency has proven to have a detrimental impact toward overall health. Vitamin D deficiency is a significant problem which requires urgent attention; hence why Vitamin D day was created!
Vitamin D day was established in 2009 in order to spread the importance of vitamin D and inform us of safe and sensible sun exposure. It is a day to recognise vitamin D deficiency across the globe, share information, educate others and learn a little something along the way.
So why is vitamin D so important for our health?
Vitamin D is important for many biological reasons. It has many imperative roles and functions in the body including;
- Accommodating calcium absorption
- Promoting strong healthy bones
- Maintaining and building healthy bones
- Maintaining muscle strength
- Potentially decreasing the risk of falls and fractures in the elderly
- Assisting and supporting healthy immune function
Vitamin D2 & D3; what is the difference?
There are 2 forms of vitamin D; Vitamin D2 or ergocalciferol which is produced by some plant life in response to UV radiation and D3 otherwise known as cholecalciferol. It is vitamin D3 that we obtain from sun exposure and what is made in our bodies.
How does the sun provide vitamin D for us?
So how does vitamin D3 actually get into our system and exert its affects? It is quite a complex, somewhat confusing, step by step process;
- Firstly our bodies manufacture vitamin D when the sun's ultraviolet B (UVB) rays interact with 7-dehydrocholesterol (7-DHC) a component present in our skin.
- 7-DHC is then converted to cholecalciferol (pre-vitamin D3) via an enzymatic reaction, which is transported to the liver.
- The liver converts cholecalciferol to 25-hydroxyvitamin D or 25 (OH) D, also known as calcifediol.
- Calcifediol is delivered to the kidneys, which forms the physiologically active form of vitamin D3; 1, 25-dihydroxyvitamin D (1, 25(OH)2D), also known as calcitriol. To keep things simple let’s just call it vitamin D3!
How much Vitamin D do we need?
The most economical way to obtain vitamin D is via daily sun exposure. The amount of sun exposure needed to maintain adequate vitamin D levels depends on many factors; geographical location, strength of UV light at the time of year and day, skin colour, age and existing serum level of vitamin D. Studies show that an average time of 30 minutes of skin in direct sunlight (without sunscreen) between 10am and 3pm in Australia is enough to maintain Vitamin D status. Rule of thumb; your shadow should be shorter than you! *Remember to always be sun smart; use protective clothing and sunscreen if spending a long amount of time in the sun.
Can we obtain vitamin D from foods?
There are certain foods that contain vitamin D, however their values are limited. Maintaining healthy vitamin D levels via food alone may prove difficult. Foods containing vitamin D include fish; particularly sardines, salmon and mackerel, eggs, mushrooms and vitamin D fortified foods. Consumption of these foods alongside adequate sun exposure may improve and maintain vitamin D levels.
How does vitamin D deficiency occur?
It’s hard to believe vitamin D deficiency exists in such a sun drenched country like ours. With much of our time being spent indoors due to work commitments and the abundant use of technology, sun exposure has been reduced dramatically. The use of sunscreen has also limited our vitamin D intake. It only makes sense to apply sunscreen to protect our skin from burning and skin cancer during the summer month’s right? Research suggests applying sunscreen at least 15-30 minutes after sun exposure in order to maintain adequate vitamin D levels.
The Research:
Unfortunately Vitamin D deficiency is an extremely common problem in Australia. According to the research approximately one third of Australian adults over the age of 25 are significantly lacking in vitamin D.
A study conducted in 2012 confirmed that vitamin D deficiency is prevalent amongst the Australian population. The study included 11, 247 participants aged over 25 years which were randomly chosen from all over Australia. Blood samples were taken from each participant and their serum concentrations of 25-hydroxyvitamin D (vitamin D) were measured. Other personal and lifestyle information on the participants was obtained via questionaries.
The results of the research showed that vitamin D deficiency significantly increased with age, was more common in women and the obese, greater in people from non-European background, people with a higher education and those who lead a sedentary lifestyle. It was also noted that there was a significant increase in deficiency during the winter months and more common in people living in southern Australia. Even in the summer-autumn months 42% of women and 27% of men were vitamin D deficient.
So let’s recognise Vitamin D this November 2nd and give it the much needed attention it deserves!
Daly, RM., et al. (2011). Prevalence of vitamin D deficiency and its determinants in Australian adults aged 25years and older: A national, population-based study. Clin Endocrinol (Oxf). 2011 Dec 15.doi: 10.1111/j.1365-2265.2011.04320.x.
