Vitamin D is one of the few vitamins our body needs that it can produce independently of our diet. This fat-soluble vitamin is unique in humans because it functions as a prohormone, a precursor to the ordinary hormone, and is synthesized when our skin is exposed to the sun. It is synthesized in the kidneys in the form of calcitriol, before it is released into the body as a hormone. It regulates the concentration of calcium and phosphate in the blood stream, helping to promote healthy growth and remodeling in our bones.
The regular intake or production of Vitamin D in our bodies can help to prevent rickets in children and the onset of osteomalacia in adults. Vitamin D, especially when combined with calcium, helps to maintain healthy bones and can also reduce the risk of osteoporosis later in life. While it is commonly known that Vitamin D is good for the health of our bones, many people do not know that it also affects the function of the neuromuscular and immune systems, inflammation and cell growth [1][2][3]. Vitamin D also partly modulates the genes in the body that regulate cell proliferation, differentiation and apoptosis [1]. What does that mean? Vitamin D helps regulate cells throughout their life cycle, which prevents cancer!
The recommended dietary intake, recommended by the Vitamin D council, is 5000 IUs for healthy adults and adolescents. Even though getting regular sunlight is the simplest way to top up Vitamin D levels, many people don’t get sufficient sun, particularly if they live in a colder climate or during the winter. Fortunately there are plenty of food sources out there that can help support our Vitamin D intake.
In some countries, it is not uncommon to come across food that has been artificially fortified with Vitamin D [4]. But the regular consumption of fatty fish, such as catfish, salmon, mackerel, sardines, eel and tuna, can help to naturally get enough Vitamin D in our diet. Other food sources are also rich in Vitamin D, such as: whole eggs, beef liver, fish liver oils – including cod liver oil, mushrooms and yeast that have been grown under UV light. Most people should opt for supplementation. The most efficient and cost-effective supplement that I recommend for this purpose is Bio-D-Mulsion Forte.
It is important to maintain a healthy balanced diet rich in Vitamin D and to get enough sunlight when the weather is nice enough to do so. Vitamin D is important for a healthy skeletal system, immune system [5], may reduce the risk against cancer [6] and may even reduce the overall mortality risks from any cause [7][8].
References:
[1] http://www.vitamindcouncil.org/about-vitamin-d/how-to-get-your-vitamin-d/vitamin-d-supplementation/
[2] Holick MF. Vitamin D. In: Shils ME, Shike M, Ross AC, Caballero B, Cousins RJ, eds. Modern Nutrition in Health and Disease, 10th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.
[3] Norman AW, Henry HH. Vitamin D. In: Bowman BA, Russell RM, eds. Present Knowledge in Nutrition, 9th ed. Washington DC: ILSI Press, 2006.
[4] DRI, Dietary reference intakes: for calcium, phosphorus, magnesium, vitamin D, and fluoride. Washington, D.C: National Academy Press. 1997. p. 250. ISBN 0-309-06350-7. Nutrition
[5] http://web.archive.org/web/20080419071840/http://www.sciencenews.org/articles/20061111/bob9.asp Accessed October 2011
[6] Ingraham, BA; Bragdon, B; Nohe, A (January 2008). “Molecular basis of the potential of vitamin D to prevent cancer”. Current Medical Research and Opinion 24 (1): 139–49.
[7] Autier P, Gandini S. Vitamin D supplementation and total mortality: a meta-analysis of randomized controlled trials. Arch Intern Med 2007;167:1730-7.
[8] Giovannucci E. Can vitamin D reduce total mortality? Arch Intern Med 2007;167:1709-10.