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Vitamin D: When Sunlight is not enough

Vitamin D: When Sunlight is not enough | Mr Vitamins
According to the current Australasian Guidelines, the health of Australians is impaired by three main nutritional deficiencies – iodine, omega-3 fats and Vitamin D.1 Vitamin D is a fat-soluble vitamin, produced in your skin upon exposure to sunlight. Even though we live in sunny Australia, it has been reported that 31% of Australian adults are Vitamin D deficient.2Vitamin insufficiency is detected year-round from Brisbane to Hobart. 3

Why you might be Vitamin D deficient?

  • Many of us work full-time in office jobs
  • We always cover up when outdoors, thanks to our national “slip, slop, slap” campaign
  • People with darker skin have more melanin which reduces the skin’s ability to make Vitamin D
  • Religious dress that requires women to cover their whole bodies
  • Obese individuals often have low levels of Vitamin D

Bone health

World-leading Vitamin D expert and endocrinologist at Boston University, Prof Michael F Holick says Vitamin D is critically important for the maintenance of bone health throughout life.

Evidence shows that:

  • Vitamin D deficiency increases bone loss that can result in osteoporosis and fracture4
  • Vitamin D deficiency causes a mineralisation defect of the skeleton known as osteomalacia.5 This bone disease is associated not only with increased risk for fracture, but also with aches and pains in your bones and muscles that is often misdiagnosed as fibromyalgia, chronic fatigue syndrome or that the patient is dysthymic, i.e. depressed
  • Vitamin D treatment can improve bone mineral density in patients with low bone mineral density that is associated with osteomalacia.\5
  • Vitamin D deficiency is not simply associated with diminished bone mass, but also greatly decreased fracture resistance of the skeleton.6 Thus, Vitamin D is important for the prevention of bone loss and osteoporosis
  • Vitamin D helps to maintain bone mineral density in patients with osteoporosis7
  • Osteoporotic medications are often ineffective if the patient is Vitamin D deficient8,9

Vitamin D and Immunity

  • You should also be aware that Vitamin D could help boost your immune response to bacterial and viral infections11
  • Having too little Vitamin D can increase your susceptibility to colds and flu, as well as our risk of developing autoimmune diseases such as multiple sclerosis and lupus11
  • Additionally, if you are pregnant and have low levels of Vitamin D, your baby may also be at increased risk of contracting a nasty chest infection12
Viatmin D' help in immunity is attributed to its role in stimulating white blood cells called macrophages, which serve to engulf infectious foreign bodies. And if that weren’t enough, Vitamin D can also activate other white blood cells (T and B lymphocytes), which also play a complex part in immune defence.

Other benefits

  • Vitamin D is one of the essential nutrients, because it cannot be produced in your body
  • Recent research also suggests increasing Vitamin D levels may not only support healthy bones but also improve immune function and reduce the risk of many other conditions14
  • A study by Boston University found that improving Vitamin D levels could positively impact the genes associated with cancer, cardiovascular disease (CVD), infectious diseases and autoimmune diseases14
  • Additionally, Vitamin D is involved in muscle growth,15 it may enhance calcium absorption,16 and may play a role in preventing osteoporotic fractures that are induced by falls17
  • Vitamin D deficiency is also a potential risk factor for obesity and the development of insulin resistance leading to type 2 diabetes.18 Therefore detecting and correcting a Vitamin D deficiency is particularly important for those individuals with a family history of metabolic syndrome and its related complications (e.g. cardiovascular disease and/or type 2 diabetes)
  • There is evidence to show that Vitamin D supplementation may assist in the maintenance of healthy heart muscle.19

 Who needs Vitamin D?

To achieve adequate levels of Vitamin D, Prof Holick says we require either increased sunlight exposure or supplementation. With Australia having some of the highest rates of skin cancer in the world, it’s important that we take sensible measures to avoid sun exposure especially at peak times, so for some populations supplementation may be a more appropriate way of getting enough Vitamin D. Excessive sunlight exposure is problematic because the same UVB rays that help us make Vitamin D also damage skin cells, causing skin ageing and contributing to skin cancer risk. Many of us are unaware that, unfortunately, only a few foods contain Vitamin D: oily fish, mushrooms exposed to ultraviolet light and some dairy products, but often not enough to satisfy your daily requirement. Some of us are more inclined to having a Vitamin D deficiency than others. Darker-skinned individuals, the elderly, people who wear concealing clothing and babies of Vitamin D deficient mothers are all more susceptible to Vitamin D deficiency. Other factors that may reduce Vitamin D absorption are malabsorption syndromes (such as Crohn’s disease) and being on certain medications such as glucocorticoids and anti-seizure drugs, which can promote Vitamin D destruction.10 This is one area where consulting an experienced Naturopath can be extremely beneficial as they will be able to assist you in assessing your risk of Vitamin D deficiency and what it could mean for your personally as well as selecting the correct supplement for your needs. ‘Ask a Naturopath’ at Mr Vitamins about which form of Vitamin D is right for you.


  1. National Health and Medical Research Council (NHMRC). Australian Dietary Guidelines (2013).  Australian Government. Viewed 1 Nov 2013,
  2. Daly RM Gagnon C, Lu ZX, et al. Prevalence of vitamin D deficiency and its determinants in Australian adults age 25 years and older: A national, population-based study. Clin Endocrinol 2012;77(1):26-35.
  3. van der Mei IA, Ponsonby AL, Engelsen O, et al. Environ Health Perspect 2007;115(8):1132-9.
  4. Priemel M, von Domarus C, Klatte TO, et. al. Bone mineralization defects and vitamin D deficiency: histomorphometric analysis of iliac crest bone biopsies and circulating 25-hydroxyvitamin D in 675 patients. JBMR 2010;25(2):305-312.
  5. Christodoulou S, Goula T, Ververidis A, et al. Vitamin D and bone disease. Biomed Res Int 2013;2013:396541.
  6. Busse B, Bale HA, Zimmermann EA, et al. Vitamin D deficiency induces early signs of aging in human bone, increasing the risk of fracture. Sci Transl Med 2013;5(193):193.
  7. Watanabe R, Okazaki R. Secondary osteoporosis or secondary contributors to bone loss fracture. Vitamin D deficiency and fracture. Clin Calcium 2013;23(9):1313-1319.
  8. Nurmi-Luthje I, Sund R, Juntunen M, et al. Post-hip fracture use of prescribed calcium plus vitamin D or vitamin D supplements and antiosteoporotic drugs is associated with lower mortality: a nationwide study in Finland. J Bone Miner Res 2011;26(8):1845-1853.
  9. Bruyere O, Reginster JY. Vitamin D status and response to antiosteoporotic therapy. Womens Health 2008;4(5):445-447.
  10.  Australian and New Zealand Bone and Mineral Society; Osteoporosis Australia; Australian College of Dermatologists; Cancer Council of Australia. Risks and benefits of sun exposure: position statement. May 2007.
  11. Braun L, Cohen M. Herbs and natural supplements: an evidence-based guide, 3rd ed., 2010.
  12.  Karatekin G, Kaya A, Salihoğlu O, et al. Eur J Clin Nutr 2009;63(4):473-7.
  13. Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2011;96(7):1911-1930.
  14. Hossein-nezhad A, Spira A, Holick MF (2013) Influence of Vitamin D Status and Vitamin D3 Supplementation on Genome Wide Expression of White Blood Cells: A Randomized Double-Blind Clinical Trial. PLoS ONE 8(3): e58725. doi:10.1371/journal.pone.0058725
  15. Grimaldi AS, Parker BA, Capizzi JA, et al. 25(OH) vitamin D is associated with greater muscle strength in healthy men and women. Med Sci Sports Exerc 2013;45(1):157-162.
  16. Dusso AS, Brown AJ, Slatopolsky E. Vitamin D. Am J Physiol Renal Physiol 2005;289(1):F8-28.
  17. Bischoff-Ferrari HA, Conzelmann M, Stahelin HB, et al. Is fall prevention by vitamin D mediated by a change in postural or dynamic balance? Oesteporos int 2006;17(5):656-663.
  18.  Grineva EN, Karonova T, Micheeva E, et al. Vitamin D deficiency is a risk factor for obesity and diabetes type 2 in women at late reproductive age. Aging (Albany NY) 2013;5(7):575-581
  19. Achinger SG, Ayus JC. The role of vitamin D in left ventricular hypertrophy and cardiac function. Kidney Int Suppl 2005;95:S37-42.