Calcium & Vitamin D
Calcium is the most abundant mineral in the body, it is stored in the bones, supporting structure and function.
Food remains the best source of calcium but supplements should be considered if dietary calcium intake is insufficient.
Vitamin D is a fat-soluble vitamin that can be:
- Found in limited dietary sources (margarine, eggs, oily fish, green peas);
- Produced in the skin via the action of sunlight (Approx. 10-15 min of sunlight a day without sunscreen)
Vitamin D helps to build strong bones and is essential for everyone throughout life. Vitamin D3 is very important to help protect our bones, your body to absorb calcium and supporting your muscles to help decrease falls, as well as helping your immune system.
How does it work?
Ultraviolet B sun rays interact with 7-dehydrocholesterol in the skin which is converted to vitamin D₃.
Vitamin D from either the sun or food binds to the Vitamin D binding protein and travels in the bloodstream to the liver.
In the liver it is converted to 25-hydroxyvitamin D3 or (25(OH)D) (calcidiol)and in the kidneys to 1,25(OH)D (calcitriol) the biologically active circulating hormone.
Calcitriol travels to the small intestine where it enables the increase of calcium absorption ultimately affecting bone health.
Ultraviolet B sun rays interact with 7-dehydrocholesterol in the skin which is converted to vitamin D₃.
Vitamin D from either the sun or food binds to the Vitamin D binding protein and travels in the bloodstream to the liver.
In the liver it is converted to 25-hydroxyvitamin D3 or (25(OH)D) (calcidiol)and in the kidneys to 1,25(OH)D (calcitriol) the biologically active circulating hormone.
Calcitriol travels to the small intestine where it enables the increase of calcium absorption ultimately affecting bone health.
References for this section are as follows:
- https://theros.org.uk/information-and-support/bone-health/nutrition-for-bones/calcium/ The Royal Osteoporosis Society, Information and support – Nutrition for bones – Calcium. Accessed February 2024.
- The Royal Osteoporosis Society. What are the Pharmacological Treatment Options? Available in the public domain: https://theros.org.uk/healthcare-professionals/courses-and-cpd/osteoporosis-resources-for-primary-care/initiation/, accessed February 2024
- Nair R, Maseeh A. Vitamin D: The “sunshine” vitamin. Journal of Pharmacology & Pharmacotherapeutics. 2012;3(2):118-126.
- Osteoporosis Guidelines For health professionals. Irish Osteoporosis Society. 2012. Available in public domain: https://www.icgp.ie/speck/properties/asset/asset.cfm?type=LibraryAsset&id=658D8B2D%2D9409%2D98E3%2D2
E7EC84B8CAC3A35&property=asset&revision=tip&disposition=inline&app=icgp&filename=IOS%5FGuidelines%5FSept%5F2012%5F1%5F%2Epdf [Accessed February 2024] - https://www.irishosteoporosis.ie/information-support/vitamin-d-osteoporosis/ The Irish Osteoporosis Society, Vitamin D and Osteoporosis, Accessed February 2024
- Hirsch, A. L. 2000. Vitamin D. Kirk-Othmer Encyclopedia of Chemical Technology.
- Holick MF. VITAMIN D: A D-LIGHTFUL SOLUTION FOR HEALTH. Journal of investigative medicine: the official publication of the American Federation for Clinical Research. 2011;59(6):872-880.
- Christakos S, Dhawan P, Porta A, Mady LJ, Seth T. Vitamin D and Intestinal Calcium Absorption. Molecular and Cellular Endocrinology. 2011;347(1-2):25-29.
The information on this website is intended for Republic of Ireland residents only
Date of preparation: September 2024
IE-CH-1612
