The evidence for the importance of vitamin D for health continues to stack up yet there has still been no consensus as to how much should be recommended for optimal health and disease prevention. Many people in the UK do not get enough vitamin D and have insufficient/deficient blood levels. There is some agreement that blood levels of vitamin D ought to be around 40-50 nmol/l and that for most people a minimum 2000iu vitamin D daily would be needed to maintain those levels. Some researchers call for higher doses of around 5000iu to be recommended.
Recently (1) a paper has been published, written by, Anthony Norman, a leading international expert in vitamin D. The paper proposes worldwide policy changes regarding people’s vitamin D daily intake amount in order to maximise the vitamin’s contribution to reducing the frequency of many diseases, including childhood rickets, adult osteomalacia, cancer, autoimmune type-1 diabetes, hypertension, cardiovascular disease, obesity and muscle weakness (2). The paper discusses the fact that at present about half of elderly North Americans and Western Europeans and probably also of the rest of the world are not receiving enough vitamin D to even maintain healthy bones let alone contribute to optimal health. Besides the intestines and bone vitamin D generates biological responses in the immune system, heart, muscle and brain. In the paper the authors state “Responsible medicine demands that worldwide vitamin D nutritional guidelines reflect current scientific knowledge about vitamin D’s spectrum of activities”.
In a press release Anthony Norman said “It is high time that worldwide vitamin D nutritional policy, now at a crossroads, reflects current scientific knowledge about the vitamin’s many benefits and develops a sound vision for the future.” “Worldwide public health is best served by a recommendation of higher daily intakes of vitamin D,” “Currently, more than half the world’s population gets insufficient amounts of this vitamin”.
In their review paper (1) the authors note that if the daily dietary intake of vitamin D was increased by 600-1000 IU in all adults above their present supply, it would bring beneficial effects on bone health in the elderly and on all major human diseases e.g., cancer, cardiovascular, metabolic and immune diseases. The researchers add, however, that if the vitamin D dietary intake were increased to 2000 IU per day and even more for subgroups of the world population with the poorest vitamin D status, it could favourably impact multiple sclerosis, type-1 diabetes, tuberculosis, metabolic syndrome, cardiovascular risk factors and most cancers (1,2).
As I have said in all of my posts on vitamin D if you rarely get out into the sunlight you may wish to consider taking a vitamin D supplement. Only small amounts of vitamin D are found in food sources such as oily fish (mackerel, salmon and sardines) and egg yolks. Vitamin D supplements may be particularly useful during the autumn and winter months and for individuals who have darker skins or who don’t go outside regularly. For most people over 18 a supplement containing up to 2000 iu/day can be considered. Too much Vitamin D can cause serious health problems so always check with your medical doctor before taking a high dose (above 2000iu daily) so that blood levels of the vitamin can be monitored. When looking for vitamin D supplements two forms are generally available. Cholecalciferol, known as vitamin D3, and ergocalciferol or vitamin D2. Cholecalciferol is generally taken to be the more potent, easily absorbed and preferred form of vitamin D
(1)Norman AW & Bouillon R. 2010. Vitamin D nutritional policy needs a vision for the future. Proceedings of the Society for Experimental Biology and Medicine. Minireview. First published on 28 July 2010. doi:10.1258/ebm.2010.010014
(2)Press release. University of California – Riverside (2010, August 9). Biochemist proposes worldwide policy change to step up daily vitamin D intake. ScienceDaily. Retrieved August 13, 2010, from http://www.sciencedaily.com /releases/2010/08/100809133325.htm
Written by Ani Kowal