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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.

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.

An evaluation of the vitamin D3 content in fish: Is the vitamin D content adequate to satisfy the dietary requirement for vitamin D? Lu Z, Chen TC, Zhang A, Persons KS, Kohn N, Berkowitz R, Martinello S, Holick MF. J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):642-4. Epub 2007 Jan 30. PMID: 17267210 doi: 10.1016/j.jsbmb.2006.12.010 Surprisingly, farmed salmon had approximately 25% of the vitamin D content as wild salmon had. The vitamin D content in fish varied widely even within species. These data suggest that the tables that list the vitamin D content are out-of-date and need to be re-evaluated. Little is known about the effect of cooking on the vitamin D content in fish. When farm salmon was baked, almost all of the vitamin D content, i.e. 240 IU of vitamin D3 was recovered from 3.5 oz. of salmon. The initial concentration in the uncooked salmon was 245 IU of vitamin D3. However, when the salmon was fried in vegetable oil, approximately 50% (123 IU of vitamin D3 was recovered.) We also evaluated the vitamin D content in mackerel which is traditionally considered to be an excellent source of vitamin D3 because of its oily content. However, in the one sample that we tested, we only observed 24 IU of vitamin D3 in 3.5 oz.

Vitamin D and skin physiology: a D-lightful story. Holick MF, Chen TC, Lu Z, Sauter E. J Bone Miner Res. 2007 Dec;22 Suppl 2:V28-33. PMID: 18290718 doi: 10.1359/jbmr.07s211 Very few foods naturally contain vitamin D, and those that do have a very variable vitamin D content. Recently it was observed that wild caught salmon had between 75% and 90% more vitamin D(3) compared with farmed salmon. The associations regarding increased risk of common deadly cancers, autoimmune diseases, infectious diseases, and cardiovascular disease with living at higher latitudes and being prone to vitamin D deficiency should alert all health care professionals about the importance of vitamin D for overall health and well being. Humans have depended on sunlight for their vitamin D requirement. The impact of season, time of day, and latitude on vitamin D synthesis is well documented.(2,3) We now report that altitude also has a dramatic influence on vitamin D3 production and that living at altitudes above 3500 m permits previtamin D3 production at a time when very little is produced at latitudes below 3400 m. It was surprising that, at 27° N in Agra (169 M), little previtamin D3 production was observed. However, there was significant air pollution that caused a haze over the city. It is likely the ozone and other UVB-absorbing pollutants in the air prevented the solar UVB photons from reaching the earth's surface to produce previtamin D3.

25-hydroxyvitamin D3 is an active hormone in human primary prostatic stromal cells. Lou YR, Laaksi I, Syvälä H, Bläuer M, Tammela TL, Ylikomi T, Tuohimaa P. FASEB J. 2004 Feb;18(2):332-4. Epub 2003 Dec 4. PMID: 14657005

Vitamin D receptor expression in normal, premalignant, and malignant human lung tissue. Menezes RJ, Cheney RT, Husain A, Tretiakova M, Loewen G, Johnson CS, Jayaprakash V, Moysich KB, Salgia R, Reid ME. Cancer Epidemiol Biomarkers Prev. 2008 May;17(5):1104-10. PMID: 18483332 doi: 10.1158/1055-9965.EPI-07-2713 onclusions: VDR expression spanned the lung carcinogenesis spectrum. Nuclear expression was similar across various histologies, whereas cytoplasmic expression decreased with increasing histologic grade. These results indicate that there is potential for the use of calcitriol as a chemopreventive agent against the development of lung cancer. (Cancer Epidemiol Biomarkers Prev 2008;17(5):1104-10)

1,25(OH)2 vitamin d inhibits foam cell formation and suppresses macrophage cholesterol uptake in patients with type 2 diabetes mellitus. Oh J, Weng S, Felton SK, Bhandare S, Riek A, Butler B, Proctor BM, Petty M, Chen Z, Schechtman KB, Bernal-Mizrachi L, Bernal-Mizrachi C. Circulation. 2009 Aug 25;120(8):687-98. Epub 2009 Aug 10. PMID: 19667238 doi: 10.1161/CIRCULATIONAHA.109.856070 Conclusion- These results identify reduced vitamin D receptor signaling as a potential mechanism underlying increased foam cell formation and accelerated cardiovascular disease in diabetic subjects.

Serum levels of free 1,25-dihydroxyvitamin D in vitamin D toxicity. Pettifor JM, Bikle DD, Cavaleros M, Zachen D, Kamdar MC, Ross FP. Ann Intern Med. 1995 Apr 1;122(7):511-3. PMID: 7872586 CONCLUSIONS: Although the patients had normal or near-normal total 1,25-(OH)2D values, most patients had elevated free 1,25-(OH)2D levels. These findings suggest that elevated free 1,25-(OH)2D levels might play a role in the pathogenesis of hypercalcemia in vitamin D toxicity.

Factors that influence the cutaneous synthesis and dietary sources of vitamin D.\nChen TC, Chimeh F, Lu Z, Mathieu J, Person KS, Zhang A, Kohn N, Martinello S, Berkowitz R, Holick MF.\nArch Biochem Biophys. 2007 Apr 15;460(2):213-7. Epub 2007 Jan 8.\nPMID: 17254541\ndoi:10.1016/j.abb.2006.12.017\n

An evaluation of the vitamin D3 content in fish: Is the vitamin D content adequate to satisfy the dietary requirement for vitamin D?\nLu Z, Chen TC, Zhang A, Persons KS, Kohn N, Berkowitz R, Martinello S, Holick MF.\nJ Steroid Biochem Mol Biol. 2007 Mar;103(3-5):642-4. Epub 2007 Jan 30.\nPMID: 17267210 \ndoi:10.1016/j.jsbmb.2006.12.010 \n

Vitamin D and skin physiology: a D-lightful story.\nHolick MF, Chen TC, Lu Z, Sauter E.\nJ Bone Miner Res. 2007 Dec;22 Suppl 2:V28-33.\nPMID: 18290718 \ndoi: 10.1359/jbmr.07s211\n

'Vitamin D Induces Innate Antibacterial Responses in Human Trophoblasts via an Intracrine Pathway.\nLiu N, Kaplan AT, Low J, Nguyen L, Liu GY, Equils O, Hewison M.\nBiol Reprod. 2009 Mar;80(3):398-406. Epub 2008 Nov 12.\nPMID: 19005165DOI: 10.1095/biolreprod.108.073577

Cutting edge: vitamin D-mediated human antimicrobial activity against Mycobacterium tuberculosis is dependent on the induction of cathelicidin.\nLiu PT, Stenger S, Tang DH, Modlin RL.\nJ Immunol. 2007 Aug 15;179(4):2060-3.\nPMID: 1767546

Human cathelicidin antimicrobial peptide (CAMP) gene is a direct target of the vitamin D receptor and is strongly up-regulated in myeloid cells by 1,25-dihydroxyvitamin D3.\nGombart AF, Borregaard N, Koeffler HP.\nFASEB J. 2005 Jul;19(9):1067-77.\nPMID: 15985530

Vitamin D3 and 25-hydroxyvitamin D3 in raw and cooked pork cuts. Ina Clausen, Jette Jakobsen, Torben Leth and Lars Ovesen. Journal of Food Composition and Analysis Volume 16, Issue 5, October 2003, Pages 575-585 doi:10.1016/S0889-1575(03)00064-4 Meat 25OHD3 contributes significantly to vitamin D activity. Food databases should include concentrations of both vitamin D and 25OHD.

Concentrations of vitamin D3 and 25-hydroxyvitamin D3 in raw and cooked New Zealand beef and lamb. Roger Purchas, Maggie Zoua, Philip Pearcea and Felicity Jackson- Journal of Food Composition and Analysis Volume 20, Issue 2, March 2007, Pages 90-98 For lamb, the highest levels of vitamin D3 were in the shoulder chop both before and after cooking, while levels were lowest in the rack muscle. Similar cut differences were shown for 25OHD3 concentrations. For beef there were no significant differences between the cuts for vitamin D3, but concentrations of 25OHD3 were lower in the striploin before and after cooking, Vitamin D3 levels tended to be higher in beef cuts than in lamb cuts, but the opposite held for 25OHD3. Concentrations of vitamin D3 were similar to those in other reports, but the 25OHD3 levels were at the high end of reported ranges. With 25OHD3 being more potent than vitamin D3, it is concluded that meat can make a useful contribution of this vitamin to the human diet.

Vitamin D-induced up-regulation of tumour necrosis factor alpha (TNF-alpha) in prostate cancer cells. Golovko O, Nazarova N, Tuohimaa P. Life Sci. 2005 Jun 17;77(5):562-77. Epub 2005 Feb 25. PMID: 15904673 doi:10.1016/j.lfs.2004.10.072 Combined addition of human recombinant TNF-alpha with calcitriol or CB1093 cause enhanced effect in induction of apoptosis. We conclude that under physiological conditions vitamin D activates only the transcription of TNF-alpha gene, for TNF-alpha protein synthesis additional cofactors are required. Therefore a cooperation of vitamin D and TNF-alpha may play an important role in the control of cell growth in prostate cancer.

25-Hydroxyvitamin D(3) is an agonistic vitamin D receptor ligand. Lou YR, Molnár F, Peräkylä M, Qiao S, Kalueff AV, St-Arnaud R, Carlberg C, Tuohimaa P. J Steroid Biochem Mol Biol. 2009 Nov 26. [Epub ahead of print] PMID: 19944755 doi:10.1016/j.jsbmb.2009.11.011 In conclusion, 25-hydroxyvitamin D3 is an agonistic vitamin D receptor ligand with gene regulatory and anti-proliferative properties.

25-Hydroxyvitamin D(3) is an agonistic vitamin D receptor ligand. Lou YR, Molnár F, Peräkylä M, Qiao S, Kalueff AV, St-Arnaud R, Carlberg C, Tuohimaa P. J Steroid Biochem Mol Biol. 2009 Nov 26. [Epub ahead of print] PMID: 19944755 doi:10.1016/j.jsbmb.2009.11.011 In conclusion, 25-hydroxyvitamin D3 is an agonistic vitamin D receptor ligand with gene regulatory and anti-proliferative properties.

Estimation and fortification of vitamin D3 in pasteurized process cheese. Upreti P, Mistry VV, Warthesen JJ. J Dairy Sci. 2002 Dec;85(12):3173-81. PMID: 12512590 The objective of this study was to develop methods for the estimation and fortification of vitamin D3 in pasteurized Process cheese. Vitamin D3 was estimated using alkaline saponification at 70°C for 30 min, followed by extraction with petroleum ether:diethyl ether (90:10 vol/vol) and HPLC. The retention time for vitamin D3 was approximately 9 min. A standard curve with a correlation coefficient of 0.972 was prepared for quantification of vitamin D3 in unknown samples. In the second phase of the study, pasteurized Process cheeses fortified with commercial water- or fat-dispersible forms of vitamin D3 at a level of 100 IU per serving (28 g) were manufactured. There was no loss of vitamin D3 during Process cheese manufacture, and the vitamin was uniformly distributed. No losses of the vitamin occurred during storage of the fortified cheeses over a 9-mo period at 21 to 29°C and 4 to 6°C. There was an approximately 25 to 30% loss of the vitamin when cheeses were heated for 5 min in an oven maintained at 232°C. Added vitamin D3 did not impart any off flavors to the Process cheeses as determined by sensory analysis. There were no differences between the water- and fat-dispersible forms of the vitamin in the parameters measured in fortified cheeses