Vitamin D aka Vitamin SUN

In a day and age where we’re told to slip, slop, slap at all times whilst we’re in the sun to prevent skin cancer and ageing, people have almost become scared of that big, beautiful, ball of flames. Sunscreen and skin coverage is great, but like everything, it is only required in moderation. Vitamin D (calciferol) is one of the most crucial yet overlooked vitamins out there, and our main source of it is directly from the sun.

When exposed to UV rays, vitamin D precursors in our skin, which are derived from cholesterol, are activated and converted to cholecalciferol (D3). This is transported to the liver and sequentially the kidneys where it changes to calcidiol and then finally calcitriol, the form that is utilised by the body. It is possible to obtain vitamin D from food, however the only good sources of it are fortified milk (98 IU), fatty fish (salmon (360 IU)), egg yolks (25 IU), and animal liver (12-30 IU), and even so, these don’t meet the recommend daily intake of 600 IU. If you’re constantly applying SPF all over, these essential UV rays don’t penetrate the skin and your wonderfully smart cells can’t produce the vitamin D that they so desperately need.

So, why is vitamin D so important?

Vitamin D is essential for a range of biological functions, but its principal function is to increase the absorption of calcium and phosphate from your gastrointestinal tract (from the food you eat) and maintain normal blood levels of these ions. This is crucial for bone strength and the remodelling of bones, which is constantly occurring. In a deficient state, bones will become soft, brittle and even misshapen (rickets in children). Therefore, sun exposure is even more necessary for the elderly as they are at a higher risk of osteoporosis, yet they are the main demographic who tend to stay indoors.

Other functions of vitamin D include maintaining normal parathyroid status, cell proliferation, differentiation and apoptosis, neuromuscular function, and immune function. Many recent studies explain the beneficial roles of vitamin D (and detrimental effect with vitamin D deficiency) in cancer prevention/treatment, cardiovascular diseases (especially high blood pressure), and interestingly, autoimmune diseases (including inflammatory bowel disease, diabetes mellitus, multiple sclerosis and rheumatoid arthritis) via its reduction of the inflammatory response. New research also links vitamin D deficiency to depression, and supplements have been used to alleviate the mental disease.

Approximately 25% of Australian adults and 41.6% of US adults are vitamin D deficient. Deficiency is more common in winter as the UV index rarely reaches a level high enough to begin calcitriol production via the skin, and we’re generally fully covered, leaving only our face and hands exposed to any potential UV rays.

If you are experiencing bone weakness, muscle pain, fatigue, depression, poor immunity or you have an autoimmune disease or osteoporosis, is it would be wise to visit your naturopath or integrative/functional doctor and have a blood test to determine your vitamin D status. I would recommend getting professional advice before self-supplementing because it is possible to overdose, and this can cause hypercalcaemia (calcification of soft tissues). Therefore, I suggest gradually increasing your sun exposure (before applying sunscreen) or taking 1/2-1 teaspoon/1 capsule of cod liver oil each day and be mindful of any effects you feels. Depending on where you live and what your skin type is, the amount of time you need to spend in the sun will differ. Use this calculator to get an estimate of the amount of sun exposure you need each day: https://fastrt.nilu.no/VitD-ez_quartMED.html

Megan // The Autoimmune Activist x

Sources

Australian Bureau of Statistics 2014, Feature Article: Vitamin D, viewed 7 March 2017,

Better Bones 2014, Food Sources of Vitamin D, viewed 7 march 2017, <http://www.betterbones.com&gt;

Christakos, S, Dhawan, P, Verstuyf, A, Verlinden, L & Carmeliet, G 2016, ‘Vitamin D: Metabolism, Molecular Mechanism of Action, and Pleiotropic Effects’, Physiological Reviews, vol. 96, pp. 365-408, viewed 7 March 2017, <https://www.ncbi.nlm.nih.gov&gt;

DeLuca, HF 2004, ‘Overview of general physiologic features and functions of vitamin D’, The American Journal of Clinical Nutrition, vol. 80, pp. 1689-1696, viewed 7 March 2017, <http://ajcn.nutrition.org&gt;

Forrest, KY & Stuhldreher, WL 2011, ‘Prevalence and correlates of vitamin D deficiency in US adults’, Nutrition Research, vol. 31, pp. 48-54, viewed 7 March 2017, <https://www.ncbi.nlm.nih.gov&gt;

Holick, MF 2004, ‘Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease’, The American Journal of Clinical Nutrition, vol. 80, pp. 1678-1688, viewed 7 March 2017, <https://www.ncbi.nlm.nih.gov&gt;

National Institutes of Health 2016, Vitamin D – Health Practitioner Fact Sheet, viewed 7 March 2017, <https://ods.od.nih.gov&gt;

Stocker, HS 2016, General, Organic and Biological Chemistry, 7th edn., Cengage Learning, Boston.

Van Belle, TL, Gysemans, C & Mathieu, C 2011, ‘Vitamin D in autoimmune, infectious and allergic diseases: A vital player?’, Clinical Endocrinology & Metabolism, vol. 25, pp. 617-632, viewed 7 March 2017, <http://www.bprcem.com&gt;

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