Have you noticed mood changes during winter or that you often get sick. Vitamin D could be the answer to this, especially if you are deficient. Find out more about the important role of vitamin D…………
Insufficient Vitamin D can lead to lowered immunity, depression and other mental health conditions. Vitamin D is also important for healthy strong bones and preventing osteoporosis. But, not only does the Vitamin D prevent osteoporosis, research suggests it may also provide protection from high blood pressure, diabetes, cancer and other autoimmune diseases.
Vitamin D is a fat soluble vitamin that is synthesised in our skin when it is exposed to UV-B rays from the sun. We also obtain small amounts from the foods we eat however it is impossible to meet our Vitamin D requirements through food alone. The amount we gain from the sun is dependent on UV radiation levels and this varies based on location, time of the year and cloud coverage. During winter most of us are unable to synthesise sufficient vitamin D as we are not exposed to the sun for long enough, our bodies are generally covered up and we spend more time indoors. The image below shows the differences in percentage of deficiencies across Australia in summer vs. winter months. You can see that the percentage of people deficient in winter almost doubles for some states compared to people deficient in the summer months.
Percentage of the Australian population deficient in Vitamin D during Summer (top) vs. Winter (bottom):
Images copied from: http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/4364.0.55.006Chapter2002011-12
We as adults require around 5.0 µg /day but this amount increases as we age with those aged 50 years or older requiring 10.0 µg /day. Sources of vitamin D include diet, sun exposure, and supplements.
How much sun?
Most of us do not get enough sunlight due to season, sunscreen use, being mostly indoors, skin pigmentation and aging which influence the production of vitamin D by the skin. If you have ever wondered how much sunlight is needed, the picture below outlines the recommended sun exposure to obtain sufficient Vitamin D during the summer and winter months in Australia:
Image copied from: http://www.osteoporosis.org.au/vitamin-d
What food sources contain Vitamin D?
Vitamin D can be found in fortified foods (e.g. milk and orange juice), fatty fish (e.g. salmon and trout), and fish oils. In Australia, it is mandatory for oils and spreads (e.g. low-fat spreads) to be fortified and voluntarily, some skim milks, powdered milks, yoghurts and cheeses are fortified. The average Australia has an estimated dietary intake 2.6 – 3.0 µg/day for men and 2.0 – 2.2 µg/day for women of vitamin D per day. This is half the recommended amount which is why exposure to sunlight is important. Supplements can assist in meeting these requirements during winter if you are deficient.
If you are concerned about your vitamin D levels best to see your local health practitioner.
- Aranow, C. (2011). Vitamin D and the Immune System. Journal of Investigative Medicine 59(6): 881–886. doi: 231/JIM.0b013e31821b8755 Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/
- Australian Bureau of Statistics. (2014). Australian Health Survey: Biomedical Results for Nutrients, 2011-12. Retrieved from http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/4364.0.55.006Chapter2002011-12
- Australian Government; Department of Health and Ageing & National Health and Medical Research Council [NHMRC]. (2006). Nutrient reference values for Australia and New Zealand. Executive summary. Canberra: Commonwealth of Australia Retrieved from http://www.nrv.gov.au/.
- Deakin Research Communications. (2012). Vitamin D deficiency strikes one-third of Australians. Retrieved from https://www.deakin.edu.au/research/stories/2012/01/16/vitamin-d-deficiency-strikes-one-third-of-australians
- Dusso, A., Brown, A., Slatopolsk, E. (2005). Vitamin D. American Journal of Physiology – Renal Physiology 289 (1), 8-28. DOI: 10.1152/ajprenal.00336.2004. Retrieved from http://ajprenal.physiology.org.ezproxy.ecu.edu.au/content/289/1/F8
- Nowson, C., & Margerison, C. (2002). Vitamin D intake and vitamin D status of Australians. Medical Journal of Australia, 177 (3), 149-152. Retrieved from https://www.mja.com.au/journal/2002/177/3/vitamin-d-intake-and-vitamin-d-status-australians?0=ip_login_no_cache%3Df7253e325ef79c273c7bb2740b8a6679
- Osteoporosis Australia Medical & Scientific Advisory Committee. (2014). Vitamin D. Osteoporosis Australia. Retrieved from http://www.osteoporosis.org.au/vitamin-d
- Penckofer, S., Kouba, J., Byrn, M., & Ferrans, C. (2010).Vitamin D and Depression: Where is all the Sunshine? Issues in Mental Health Nursing, 31(6): 385–393.doi: 3109/01612840903437657. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908269/