Vitamin D: What’s all the fuss about?
With all the hype surrounding vitamin D supplementation, as well as the high vitamin D deficiency rate in Australians, it’s time to clarify what exactly this complex vitamin does and why it is so important. Find out everything you need to know on vitamin D here from my Q and A with nutritionist and dietitian Belinda Reynolds.
What are the best natural sources of vitamin D?
Vitamin-D is a fat-soluble vitamin, produced in our skin upon exposure to sunlight. For adequate vitamin D, the suggested amount of sun exposure is between just 5 and 15 minutes, 4 to 6 times a week.[i]
Many of us are unaware that, unfortunately, only a few foods contain vitamin D: oily fish, fortified milk and margarine, eggs and ultraviolet light-exposed mushrooms. That’s it, which explains why it is hard for us to achieve sufficient vitamin D levels solely through diet.[ii]
Why are so many Australians deficient in vitamin D?
The statistic that 58% of Australians could be vitamin D deficient during the spring months[iii] is a concern. However, it is not surprising. Yes, many of us may live in sunny Australia, but we also may get less sun exposure and therefore less vitamin D in the colder seasons.[iv] What’s more, many of us work in full-time office jobs and are always covering up when we finally do head outdoors. Did you know that SPF 30+ sunscreen decreases up to 95% of the skin’s ability to produce vitamin D?
Some of us are more inclined to having a vitamin D deficiency than others, with factors such as skin colour and age. 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.[v] 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.
What are the symptoms of vitamin D deficiency and how can we determine if we have inadequate levels?
It is easy to be vitamin D deficient without knowing it, because unlike some other vitamin deficiencies, vitamin D deficiency presents with few symptoms. You may be tired and have general body aches and pains, but some people may not have any symptoms at all.[vi]
The best way to check if you have a vitamin D deficiency is to have your GP give you a referral for a blood test of your vitamin D levels. Considering that one in three GPs admit that more than 40% of their tested patients were found to be lacking in vitamin D[vii], having a blood test to check your levels can be worthwhile. Early detection and correction of vitamin D deficiency is significant before associated illnesses set in, such as osteoporosis.
What about the potential health benefits of a vitamin D supplement?
There is evidence to show that vitamin D supplementation may assist in the maintenance of healthy heart muscle[viii], support healthy bone mineralisation required for healthy growth of bones in children, and may reduce the risk of falls and fractures in older adults.[ix] [x] Vitamin D is also involved in muscle growth[xi], it may enhance calcium absorption[xii], and may influence postural/dynamic balance[xiii], the latter being relevant seeing that osteoporotic fractures may be induced by falls.
Vitamin D deficiency is also a potential risk factor for obesity and the development of insulin resistance leading to type 2 diabetes.[xiv] 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).
While many of us may know about vitamin D’s role in bone health, and that adequate levels are required as a measure against osteoporosis development, we should also be aware of the part it plays in immune function. This 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. Recently, it was observed by vitamin D expert Professor Michael Holick and associates that vitamin D from a supplement regulates 291 genes that control over 80 metabolic processes, including those involving immune function, DNA repair and responses to environmental toxins that create oxidative stress.
This vitamin does A LOT! What are the key points to take away from the findings on vitamin D?
It sure does! The science behind the many roles of vitamin D is highly complex, but there is no need for us to feel overwhelmed by this. What we should keep in mind is the big picture relating to vitamin D, being that it may play an important part in our bone, muscle and immune health. Also, think about how much sunlight exposure you are getting each week; if it is none or close to none, it may be worth your while to speak to your naturopath or health practitioner about whether supplementing with vitamin D may benefit you.
Speak to your healthcare practitioner for more information about boosting your immune system.
Always speak to your healthcare professional when considering supplementation. When taking supplements, make sure to always read the label and use only as directed. If symptoms persist see your healthcare practitioner and remember that vitamin supplements should not replace a balanced diet.
For more health articles, go to www.bioceuticals.com.au/education/articles
Belinda Reynolds Belinda Reynolds graduated with an Honours Degree in Nutrition and Dietetics in 2003. She has been involved in the complementary medicine industry for nearly 14 years – nine of these working for BioCeuticals as a Practitioner Sales Consultant, Team Leader, Presenter, Educator and Writer, with an involvement in Marketing and Product Development. Outside of this Belinda has spent time working in hospitals and lectured at the Australasian College of Natural Therapies. Belinda’s greatest passion is assisting practitioners in developing their knowledge by presenting new research in the area of integrative medicine. Now a mother of two, pre- and postnatal, infant and child health have evolved as subjects particularly close to her heart.
[i] Nowson CA, Diamond TH, Pasco JA, et al. Vitamin D in Australia. Issues and recommendations. Aust Fam Physician 2004;33:133-138.
[ii] Nowson CA, Margerison C. Vitamin D intake and vitamin D status of Australians. Med J Aust 2002;177:149-152.
[iii] Boyages S, Bilinski K. Seasonal reduction in vitamin D level persists into spring in NSW Australia: implications for monitoring and replacement therapy. Clinical Endocrinology 2102;77:515–523.
[iv]Joshi D, Center RJ, Eisman JA. Vitamin D deficiency in adults. Australian Prescriber 2012. Viewed 16 August 2013, http://www.australianprescriber.com/magazine/33/4/103/6
[v] 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, http://www.cancer.org.au/content/pdf/CancerControlPolicy/PositionStatements/PSRisksBenefitsSunExposure03May07.pdf
[vi] Am I Deficient in Vitamin D? Vitamin D Council. Viewed 16 August 2013, http://www.vitamindcouncil.org/about-vitamin-d/am-i-deficient-in-vitamin-d/
[vii] Rose D. Explosion in vitamin D testing reflects need for simple sun rules. Medical Observer 21 Jun 2011, http://www.medicalobserver.com.au/news/explosion-in-vitamin-d-testing-reflects-need-for-simple-sun-rules
[viii] Achinger SG, Ayus JC. The role of vitamin D in left ventricular hypertrophy and cardiac function. Kidney Int Suppl 2005;95:S37-42.
[ix] Stipanuk M. Biochemical, physiological and molecular aspects of human nutrition, 2nd ed. St Louis: Saunders Elsevier, 2006.
[x] Bischoff-Ferrari HA, Dawson-Hughes B. Where do we stand on vitamin D? Bone 2007;41(1 Suppl 1):S13-19.
[xi] 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.
[xii] Dusso AS, Brown AJ, Slatopolsky E. Vitamin D. Am J Physiol Renal Physiol 2005;289(1):F8-28.
[xiii] 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.
[xiv] 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