“The Sunshine Vitamin”

  • healthy bones
  • immune support

Vitamin D is one of the many nutrients our bodies need to stay healthy. It can either be synthesised in the human epidermis, or taken through certain foods and supplements.

For most people Vitamin D is made by their own body with the help of sunlight. The amount of vitamin D that the skin makes is however dependent on various factors: season (usually less sunshine in winter months), the time of day (sun rays are most powerful between 10 am and 3 pm), length of day, cloud cover, smog, skin melanin content, and the use of sunscreen.1 It is also useful to know that UVB radiation does not penetrate glass, so exposure to sunshine through a window does not help produce sufficient vitamin D.

In many countries in Northern Europe the majority of the population’s vitamin D level is under the optimum level during winter. 2

Very few foods naturally contain vitamin D. The best food sources for vitamin D are fatty fish (tuna, salmon and mackerel), beef liver, cheese, egg yolks and mushrooms.

Vitamin D is essential for general health and strong bones. It controls various processes in the body and its primary role is to participate in the regulation of metabolism of calcium and phosphorus. Studies have shown that vitamin D prevents the development of inflammatory and autoimmune diseases.3 Subjects who were deficient in vitamin D were susceptible to infectious disease and poor immune function.4,5


  1. Vitamin D – Fact Sheet for Health Professionals. National Institute of Health – Office of Dietary Supplements, National Institute of Health – Office of Dietary Supplements, 2016
  2. Spiro, Buttriss: Vitamin D: An overview of vitamin D status and intake in Europe (
  3. Tam, M., Gomez, S., Gonzalez-Gross, M., & Marcos, A. (2003). Possible roles of magnesium on the immune system. European journal of clinical nutrition, 57(10), 1193
  4. BELFRIT List, Accessed June 15, 2018.
  5. Hewison, Martin. (2011). Vitamin D and immune function: An overview. The Proceedings of the Nutrition Society. 71. 50-61. 10.1017/S0029665111001650.

Other sources:

Cantorna, M. T., Zhu, Y., Froicu, M., & Wittke, A. (2004). Vitamin D status, 1, 25-dihydroxyvitamin D3, and the immune system. The American journal of clinical nutrition, 80(6), 1717S-1720S.

Hart, P. H., Gorman, S., & Finlay-Jones, J. J. (2011). Modulation of the immune system by UV radiation: more than just the effects of vitamin D?. Nature Reviews Immunology, 11(9), 584.

Ince, Bilsev & Yildirim, Mehmet & İsmayılzade, Majid & Dadaci, Mehmet. (2018). Vitamin D and Systemic Effects of Vitamin D Deficiency. Selcuk Tip Dergisi. 2. 10.30733/std.2018.01052.

Urashima, Mitsuyoshi & Segawa, Takaaki & Okazaki, Minoru & Kurihara, Mana & Wada, Yasuyuki & Ida, Hiroyuki. (2010). May) Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. The American journal of clinical nutrition. 91. 1255-60. 10.3945/ajcn.2009.29094.