On 29th September, Dr Michael Holick appeared on the "Coast to Coast" radio show, hosted by George Noory:
http://www.coasttocoastam.com/guest/holick-dr-michael/41323
As many of you can't afford a subscription to listen to the whole show, I have edited the broadcast into an MP3 file of short snippets, so that we can (intelligently) discuss what was said. There is a "beep tone" to separate each snippet of info.
You can download it from:
http://MarshallProtocol.com/video/Holick.mp3
First is the introduction, setting out Dr Holick's overview of Vit D.
The Vitamin D Pandemic and its Health Consequences\nPresented by Michael Holick, PhD, MD, Professor of medicine, physiology and biophysics and director of the General Clinical Research Center at Boston University Medical Center\nKeynote address at the opening ceremony of the 34th European Symposium on Calcified Tissues, Copenhagen 5 May, 2007\n
Vitamin D2 is as effective as vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D.
Holick MF, Biancuzzo RM, Chen TC, Klein EK, Young A, Bibuld D, Reitz R, Salameh W, Ameri A, Tannenbaum AD.
J Clin Endocrinol Metab. 2008 Mar;93(3):677-81. Epub 2007 Dec 18.
PMID: 18089691
Conclusion: A 1000 IU dose of vitamin D2 daily was as effective as 1000 IU vitamin D3 in maintaining serum 25-hydroxyvitamin D levels and did not negatively influence serum 25-hydroxyvitamin D3 levels. Therefore, vitamin D2 is equally as effective as vitamin D3 in maintaining 25-hydroxyvitamin D status.
Prevalence of Vitamin D inadequacy among postmenopausal North American women receiving osteoporosis therapy.
Holick MF, Siris ES, Binkley N, Beard MK, Khan A, Katzer JT, Petruschke RA, Chen E, de Papp AE.
J Clin Endocrinol Metab. 2005 Jun;90(6):3215-24. Epub 2005 Mar 29.
PMID: 15797954
doi:10.1210/jc.2004-2364
Conclusions: More than half of North American women receiving therapy to treat or prevent osteoporosis have vitamin D inadequacy, underscoring the need for improved physician and public education regarding optimization of vitamin D status in this population.
Holick, M. F., MacLaughlin, J. A. & Doppelt, S. H. (1981)
Factors that influence the cutaneous photosynthesis of previtamin D3. Science 211:590-593
When human skin was exposed to simulated solar ultraviolet radiation, epidermal 7-dehydrocholesterol was converted to previtamin D3. During prolonged exposure to simulated solar ultraviolet radiation, the synthesis of previtamin D3 reached a plateau at about 10 to 15 percent of the original 7-dehydrocholesterol content, and previtamin D3 was photoisomerized to two biologically inert isomers, lumisterol3 and tachysterol3. Increases either in skin melanin concentration or in latitude necessitated increases in the exposure time to simulated solar ultraviolet radiation required to maximize the formation, but not the total content, of previtamin D3. In order of importance, the significant determinants limiting the cutaneous production of previtamin D3 are (i) photochemical regulation, (ii) pigmentation, and (iii) latitude.
Vitamin D deficiency: a worldwide problem with health consequences.
Holick MF, Chen TC.
Am J Clin Nutr. 2008 Apr;87(4):1080S-6S. Review.
PMID: 18400738
A reevaluation needs to take place of what the adequate intakes of vitamin D should be for children and adults. The literature over the past decade suggests that the Institute of Medicine recommendations in 1997 (83) are inadequate, and some experts including us suggest that both children and adults should take ≥800-1000 IU vitamin D/d from dietary and supplemental sources (4, 9, 77) when sunlight is unable to provide it. This recommendation, however, has not yet been embraced either by official government or pediatric organizations in the United States, Canada, or Europe for either children or adults.
Environmental factors that influence the cutaneous production of vitamin D.
Holick MF.
Am J Clin Nutr. 1995 Mar;61(3 Suppl):638S-645S. Review.
PMID: 7879731
Holick MF.
Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease.
Am J Clin Nutr. 2004 Dec;80(6 Suppl):1678S-88S. Review.
PMID: 15585788 [PubMed - indexed for MEDLINE]
Schematic diagram of cutaneous production of vitamin D and its metabolism and regulation for calcium homeostasis and cellular growth - Figure 3 from the study
Holick MF. Sunlight and vitamin D for bone health and prevention of autoimmune diseases, can
Matsuoka, L. Y., Wortsman, J., Hanifan, N. & Holick, M. F. (1988)
Chronic sunscreen use decreases circulating concentrations of 25-hydroxyvitamin D: a preliminary study.
Arch. Dermatol. 124:1802-1804
An evaluation of the relative contributions of exposure to sunlight and of diet to the circulating concentrations of 25-hydroxyvitamin D in an elderly nursing home population in Boston.
Webb AR, Pilbeam C, Hanafin N, Holick MF.
Am J Clin Nutr. 1990 Jun;51(6):1075-81.
PMID: 2349922
Aging decreases the capacity of human skin to produce vitamin D3.
MacLaughlin J, Holick MF.
J Clin Invest. 1985 Oct;76(4):1536-8.
PMID: 2997282
doi:10.1172/JCI112134
An evaluation of surgically obtained skin (age range, 8-92 yr) revealed that there is an age-dependent decrease in the epidermal concentrations of provitamin D3 (7-dehydrocholesterol). To ascertain that aging indeed decreased the capacity of human skin to produce vitamin D3, some of the skin samples were exposed to ultraviolet radiation and the content of previtamin D3 was determined in the epidermis and dermis. The epidermis in the young and older subjects was the major site for the formation of previtamin D3, accounting for greater than 80% of the total previtamin D3 that was produced in the skin. A comparison of the amount of previtamin D3 produced in the skin from the 8- and 18-yr-old subjects with the amount produced in the skin from the 77- and 82-yr-old subjects revealed that aging can decrease by greater than twofold the capacity of the skin to produce previtamin D3. Recognition of this difference may be extremely important for the elderly, who infrequently expose a small area of skin to sunlight and who depend on this exposure for their vitamin D nutritional needs.
Sunlight regulates the cutaneous production of vitamin D3 by causing its photodegradation.
Webb AR, DeCosta BR, Holick MF.
J Clin Endocrinol Metab. 1989 May;68(5):882-7.
PMID: 2541158
doi:10.1210/jcem-68-5-882
Vitamin D3 proved to be exquisitely sensitive to sunlight, and once formed in the skin, exposure to sunlight resulted in its rapid photodegradation to a variety of photoproducts, including 5,6-transvitamin D3, suprasterol I, and suprasterol II.suprasterol I, and suprasterol II.
nfluence of season and latitude on the cutaneous synthesis of vitamin D3: exposure to winter sunlight in Boston and Edmonton will not promote vitamin D3 synthesis in human skin.
Webb AR, Kline L, Holick MF.
J Clin Endocrinol Metab. 1988 Aug;67(2):373-8.
PMID: 2839537
doi:10.1210/jcem-67-2-373
These results quantify the dramatic influence of changes in solar UVB radiation on cutaneous vitamin D3 synthesis and indicate the latitudinal increase in the length of the "vitamin D winter" during which dietary supplementation of the vitamin may be advisable.
Vitamin D status: measurement, interpretation, and clinical application.
Holick MF.
Ann Epidemiol. 2009 Feb;19(2):73-8. Epub 2008 Mar 10. Review.
PMID: 18329892
Conclusion
The only way to determine whether a person is vitamin D deficient or sufficient is to measure their circulating level of 25(OH)D. There are a variety of assays used to measure 25(OH)D. The radioimmunoassays and competitive protein binding assays for 25(OH)D are useful in detecting vitamin D deficiency and sufficiency. However, these assays are fraught with technical difficulties, especially if they are not run routinely (Fig. 4) (33). Several reference laboratories have now switched to LC-MS ,which measures both 25(OH)D2 and 25(OH)D3 quantitatively. The total 25(OH)D, i.e., 25(OH)D2 plus 25(OH)D3, is what physicians need to be aware of for their patients. A level >30 ng/mL is
Factors that influence the cutaneous synthesis and dietary sources of vitamin D.
Chen TC, Chimeh F, Lu Z, Mathieu J, Person KS, Zhang A, Kohn N, Martinello S, Berkowitz R, Holick MF.
Arch Biochem Biophys. 2007 Apr 15;460(2):213-7. Epub 2007 Jan 8.
PMID: 17254541
doi: 10.1016/j.abb.2006.12.017
Vitamin D is rare in food. Among the vitamin D-rich food, oily fish are considered to be one of the best sources. Therefore, we analyzed the vitamin D content in several commonly consumed oily and non-oily fish. The data showed that farmed salmon had a mean content of vitamin D that was ~25% of the mean content found in wild caught salmon from Alaska, and that vitamin D2 was found in farmed salmon, but not in wild caught salmon. The results provide useful global guidelines for obtaining sufficient vitamin D3 by cutaneous synthesis and from dietary intake to prevent vitamin D deficiency and its health consequences.ensuing illness, especially, bone fractures in the elderly.