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Vitamin D Information Sheet
There is growing evidence for the importance of vitamin D in long term health and that deficiency may be a key factor in chronic diseases.
Why is vitamin D important?
Vitamin D is a pro-hormone involved in the working of more than 1000 genes in our body(1)and deficiency has been associated with:
Sources of Vitamin D
Our body can synthesise vitamin D by skin exposure to UVB light and just 15-20 minutes in full sun twice a week with bare hands and face is considered sufficient.
However in our northern latitudes this only applies from April to September so deficiencies may occur in winter.
Naturally rich sources of vitamin D in our diet are limited to oily fish so supplementation offers a way to boost levels.
Vitamin D supplements come in two forms; vitamin D2 (ergocalciferol) from plants and D3 (cholecalciferol) which is the form the body naturally makes when exposed to sunshine and is generally considered to be more bioavailable than D2.
Concerns have been raised that high levels of vitamin D may elevate blood calcium however a review of human studies showed doses as high as 10,000IU per day to be safe(12) even the UK Expert Group on Vitamins and Minerals acknowledged 4000IU per day is unlikely to affect blood calcium levels(13).
To establish if a deficiency exists and select a suitable vitamin D dose a blood test would be recommended. Check with Gaia for home test kits.
1. Hart G (2010) vitamin D and ageing related disorders. The Nutrition Practitioner Summer 2010
2. Bischoff-Ferrari HA and Willett WC et al (2005) Fracture prevention with vitamin D supplementation: A meta-analysis of randomised controlled trials. JAMA 293(3):2257-2264
3. Pfeiffer M et al (2001) Effects of short-term vitamin D(3) and calcium supplementa-tion on blood pressure and parathyroid hormone levels in elderly women. J Clin Endocrinol & Metab 86(4):1633-1637
4. Wang TJ et al (2008) Vitamin D deficiency and risk of cardiovascular disease. Circulation 117(4):503-511
5. White JH (2008) Vitamin D Signaling, Infectious Diseases, and Regulation of In-nate Immunity. Infection & Immunity 76(9):3837-3843
6. Holick MF (2008)The vitamin D deficiency pandemic and consequences for non-skeletal health: mechanisms of action. Mol Aspects Med 29(6):361-8
7. Borissova AM et al (2003) The effect of vitamin D3 on insulin sensitivity in type 2 diabetic patients. Int J Clin Prac 57(4):258-261
8. Plotnikoff GA et al (2003) Prevalence of Severe Hypovitaminosis D in Patients With Persistent, Nonspecific Musculoskeletal Pain. Mayo Clin Proc 78(12):1463-70.
9. Gloth FM , Alam W and Hollis B(1999)Vitamin D vs broad spectrum phototherapy in the treatment of seasonal affective disorder. J Nutr Health Aging 3(1):5-7.
10. Thys-Jacobs S(1994) Vitamin D and Calcium in Menstrual Migraine. Headache 34(9):544-6
11. Holick MF (2004) Vitamin D: importance in the prevention of cancers, type 1 dia-betes, heart disease, and osteoporosis. Am J Clin Nutr 79(3):362-71
12. Hathcock JN et al ((2007) Risk assessment for vitamin D. Am J Clin Nutr 85(1):6-18
13, EGVM:Expert Group on Vitamins and Minerals (2003) Safe Upper Limits For Vita-mins and Minerals. London, FSA http://www.food.gov.uk/multimedia/pdfs/vitmin2003.pdf