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Measurement of vitamin D levels in inflammatory bowel disease patients reveals a subset of Crohn's disease patients with elevated 1,25-dihydroxyvitamin D and low bone mineral density. Abreu MT, Kantorovich V, Vasiliauskas EA, Gruntmanis U, Matuk R, Daigle K, Chen S, Zehnder D, Lin YC, Yang H, Hewison M, Adams JS. Gut. 2004 Aug;53(8):1129-36. PMID: 15247180 doi: 10.1136/gut.2003.036657. Conclusions: These data demonstrate that elevated 1,25(OH)2D is more common in CD than previously appreciated and is independently associated with low bone mineral density. The source of the active vitamin D may be the inflamed intestine. Treatment of the underlying inflammation may improve metabolic bone disease in this subgroup of patients.

Association of low 25-hydroxyvitamin D concentrations with elevated parathyroid hormone concentrations and low cortical bone density in early pubertal and prepubertal Finnish girls. Cheng S, Tylavsky F, Kröger H, Kärkkäinen M, Lyytikäinen A, Koistinen A, Mahonen A, Alen M, Halleen J, Väänänen K, Lamberg-Allardt C. Am J Clin Nutr. 2003 Sep;78(3):485-92. Erratum in: Am J Clin Nutr. 2006 Jan;83(1):174. PMID: 12936933 CONCLUSIONS: Vitamin D-deficient girls have low cortical BMD and high iPTH concentrations, which are consistent with secondary hyperparathyroidism. A low vitamin D concentration accompanied by high bone resorption (TRAP 5b) may limit the accretion of bone mass in young girls.

A seasonal variation of calcitropic hormones, bone turnover and bone mineral density in early and mid-puberty girls - a cross-sectional study. Viljakainen HT, Palssa A, Kärkkäinen M, Jakobsen J, Cashman KD, Mølgaard C, Lamberg-Allardt C. Br J Nutr. 2006 Jul;96(1):124-30. PMID: 16870000 Seasonal variation in S-25-OHD and bone remodelling markers accompanied by negative correlation between S-25-OHD and S-iPTH was seen in this cross-sectional study of adolescent girls. In addition, the seasonal rhythm contributed 7.0-7.6 % difference in the BMD of lumbar vertebrae and left femur in early puberty girls. This variation should be avoided since it could hamper peak bone mass attainment.

[Low levels of 25-hydroxyvitamin D (25OHD) in patients with inflammatory bowel disease and its correlation with bone mineral density] Souza HN, Lora FL, Kulak CA, Mañas NC, Amarante HM, Borba VZ. Arq Bras Endocrinol Metabol. 2008 Jun;52(4):684-91. Portuguese. PMID: 18604382

Vitamin D status affects serum parathyroid hormone concentrations during winter in female adolescents: associations with forearm bone mineral density. Outila TA, Kärkkäinen MU, Lamberg-Allardt CJ. Am J Clin Nutr. 2001 Aug;74(2):206-10. PMID: 11470722 Conclusion: A large percentage of adolescent females have low vitamin D status during the winter in Finland, which seems to have negative effects on bone health.

Vitamin D deficiency is associated with worse cognitive performance and lower bone density in older African Americans. Wilkins CH, Birge SJ, Sheline YI, Morris JC. J Natl Med Assoc. 2009 Apr;101(4):349-54. PMID: 19397226 CONCLUSIONS: Vitamin D deficiency in older African Americans was associated with worse cognitive performance and lower BMD of the hip

Strong correlations have been noted between cardiovascular diseases and low bone density / osteoporosis-connections so strong that the presence of one is considered a likely predictor of the other. This relationship has led to the hypothesis that these conditions share core pathophysiological mechanisms. Recent advances in our understanding of the complimentary roles played by vitamin D3 and vitamin K2 in vascular and bone health provide support for this hypothesis, along with insight into key metabolic dysfunctions underlying cardiovascular disease and osteoporosis. Part II, The Vitamin K Connection to Cardiovascular Health, reviews the ways in which vitamin K regulates calcium utlization, preventing vascular and soft tissue calcification while complimenting the bone-building actions of vitamin D, and also discusses vitamin K safety and dosage issues, and the necessity of providing vitamin K and vitamin A along with vitamin D to preclude adverse effects associated with hypervitaminosis D.

Strong correlations have been noted between cardiovascular diseases and low bone density / osteoporosis-connections so strong that the presence of one type of pathology is considered a likely predictor of the other. This potentially causal relationship has led to the hypothesis that these conditions share core mechanisms. Recent advances in our understanding of the complimentary roles played by vitamin D3 and vitamin K2 in vascular and bone health provide support for this hypothesis, along with insight into key metabolic dysfunctions underlying cardiovascular disease and osteoporosis. Part I of this review summarizes current research linking vitamin D deficiency to cardiovascular disease, the physiological mechanisms underlying vitamin D's cardiovascular effects, and leading vitamin D researchers' recommendations for significantly higher supplemental doses of the pro-hormone. Part II reviews the vitamin K connection to cardiovascular disease; the ways in which vitamin D and vitamin K pair up to prevent inflammation, vascular calcification and osteoporosis; and the necessity of providing vitamin K along with vitamin D to preclude adverse effects associated with hypervitaminosis D, which include vascular and other soft tissue calcification.

Relation of body fat indexes to vitamin D status and deficiency among obese adolescents. Lenders CM, Feldman HA, Von Scheven E, Merewood A, Sweeney C, Wilson DM, Lee PD, Abrams SH, Gitelman SE, Wertz MS, Klish WJ, Taylor GA, Chen TC, Holick MF; Elizabeth Glaser Pediatric Research Network Obesity Study Group. Am J Clin Nutr. 2009 Sep;90(3):459-67. Epub 2009 Jul 29. PMID: 19640956 RESULTS: The mean (+/-SD) age of the adolescents was 14.9 +/- 1.4 y; 38 (66%) were female, and 8 (14%) were black. The mean (+/-SD) body mass index (in kg/m(2)) was 36 +/- 5, FM was 40.0 +/- 5.5%, and VAT was 12.4 +/- 4.3%. Seventeen of the adolescents were vitamin D deficient, but none had elevated PTH concentrations. Bone mineral content and bone mineral density were within 2 SDs of national standards. In a multivariate analysis, 25(OH)D decreased by 0.46 +/- 0.22 ng/mL per 1% increment in FM (beta +/- SE, P = 0.05), whereas PTH decreased by 0.78 +/- 0.29 pg/mL per 1% increment in VAT (P = 0.01). CONCLUSIONS: To the best of our knowledge, our results show for the first time that obese adolescents with 25(OH)D deficiency, but without elevated PTH concentrations, have a bone mass within the range of national standards (+/-2 SD). The findings provide initial evidence that the distribution of fat may be associated with vitamin D status, but this relation may be dependent on metabolic factors

Summary of evidence-based review on vitamin D efficacy and safety in relation to bone health. Cranney A, Weiler HA, O'Donnell S, Puil L. Am J Clin Nutr. 2008 Aug;88(2):513S-519S. Review. PMID: 18689393 We found inconsistent evidence of an association between serum 25-hydroxyvitamin D [25(OH)D] concentration and bone mineral content in infants and fair evidence of an association with bone mineral content or density in older children and older adults. The evidence of an association between serum 25(OH)D concentration and some clinical outcomes (fractures, performance measures) in postmenopausal women and older men was inconsistent, and the evidence of an association with falls was fair. We found good evidence of a positive effect of consuming vitamin D-fortified foods on 25(OH)D concentrations. The evidence for a benefit of vitamin D on falls and fractures varied. We found fair evidence that adults tolerated vitamin D at doses above current dietary reference intake levels, but we had no data on the association between long-term harms and higher doses of vitamin D.

Robert P. Heaney is John A. Creighton University Professor, Creighton University, Omaha, Nebraska, United States. Hominid evolution took place in an environment (equatorial East Africa) that provided a superabundance of both calcium and vitamin D, the first in available foods and the second through conversion of 7-dehydrocholesterol to pre-vitamin D in the skin, a reaction catalysed by the intense solar ultraviolet (UV) radiation. Seemingly as a consequence, the evolving human physiology incorporated provisions to prevent the potential of toxic excesses of both nutrients. For vitamin D the protection was of two sorts: skin pigmentation absorbed the critical UV wavelengths and thereby limited dermal synthesis of cholecalciferol; and slow delivery of vitamin D from the skin into the bloodstream left surplus vitamin in the skin, where continuing sun exposure led to its photolytic degradation to inert compounds. For calcium, the adaptation consisted of very inefficient calcium absorption, together with poor to absent systemic conservation. The latter is reflected in unregulated dermal calcium losses, a high sensitivity of renal obligatory calcium loss to other nutrients in the diet and relatively high quantities of calcium in the digestive secretions. Today, chimpanzees in the original hominid habitat have diets with calcium nutrient densities in the range of 2 to 2.5 mmol per 100 kcal, and hunter-gatherer humans in Africa, South America and New Guinea still have diets very nearly as high in calcium (1.75 to 2 mmol per 100 kcal) (Eaton and Nelson, 1991). With energy expenditure of 3 000 kcal per day (a fairly conservative estimate for a contemporary human doing physical work), such diets would provide substantially in excess of 50 mmol of calcium per day. By contrast, median intake in women in North America and in many European countries today is under 15 mmol per day. Two factors altered the primitive situation: the migration of humans from Africa to higher latitude

"Thursday, 17 December 2009 This blog is in response to Dr Briffa's post here. as I keep having problems commenting on his blogs. While 44ng/ml is sufficient to not only maximize uptake of calcium (>32ng/ml) and ensure maximum bone mineral density (>42ng/ml), pregnant and nursing mothers should be aware that in order to maximize the amount of vitamin D3 in human breast milk 6400iu/daily was found to be necessary to raise (>58ng/ml) at latitude 32. This is detailed in the Taylor, Wagner and Hollis paper. Vitamin D supplementation during lactation to support infant and mother. Although 4000iu/daily met the mothers daily needs in full it left babies being born with lower 25(OH)D status than required for optimum calcium absorption They also found DAILY use of supplements was required by pregnant and nursing mothers to ensure an even daily Vitamin D3 supply to the foetus & baby. It makes virtually no measurable difference for everyone else if you supplement daily or weekly. While Dr Briffa will not be lactating he may be interested seeing in the Grassrootshealth chart showing disease incidence by 25(OH)D status. this may encourage him to go just another 10ng/ml higher and a bit nearer to the natural level at which human breast milk flows replete with D3."

Optimal serum 25-hydroxyvitamin D levels for multiple health outcomes. Bischoff-Ferrari HA. Adv Exp Med Biol. 2008;624:55-71. Review. PMID: 18348447 DOI: 10.1007/978-0-387-77574-6_5 Recent evidence suggests that higher vitamin D intakes beyond current recommendations may be associated with better health outcomes. In this chapter, evidence is summarized from different studies that evaluate threshold levels for serum 25(OH)D levels in relation to bone mineral density (BMD), lower extremity function, dental health, risk of falls, admission to nursing home, fractures, cancer prevention and incident hypertension. For all endpoints, the most advantageous serum levels for 25(OH)D appeared to be at least 75 nmol/l (30 ng/ml) and for cancer prevention, desirable 25(OH)D levels are between 90-120 nmol/l (36-48 ng/ml). An intake of no less than 1000IU (25 meg) of vitamin D3 (cholecalciferol) per day for all adults may bring at least 50% of the population up to 75 nmol/l. Thus, higher doses of vitamin D are needed to bring most individuals into the desired range. While estimates suggest that 2000 IU vitamin D3 per day may successfully and safely achieve this goal, the implications of 2000 IU or higher doses for the total adult population need to be addressed in future studies.