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Matti Narkia

The roles of calcium and vitamin D in skeletal health: an evolutionary perspective - Ro... - 0 views

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    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
Matti Narkia

Vitamin D and calcium insufficiency-related chronic diseases: molecular and cellular pa... - 0 views

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    Vitamin D and calcium insufficiency-related chronic diseases: molecular and cellular pathophysiology. Peterlik M, Cross HS. Eur J Clin Nutr. 2009 Dec;63(12):1377-86. Epub 2009 Sep 2. PMID: 19724293 doi:10.1038/ejcn.2009.105 A compromised vitamin D status, characterized by low 25-hydroxyvitamin D (25-(OH)D) serum levels, and a nutritional calcium deficit are widely encountered in European and North American countries, independent of age or gender. Both conditions are linked to the pathogenesis of many degenerative, malignant, inflammatory and metabolic diseases. Studies on tissue-specific expression and activity of vitamin D metabolizing enzymes, 25-(OH)D-1alpha-hydroxylase and 25-(OH)D-24-hydroxylase, and of the extracellular calcium-sensing receptor (CaR) have led to the understanding of how, in non-renal tissues and cellular systems, locally produced 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) and extracellular Ca2+ act jointly as key regulators of cellular proliferation, differentiation and function. Impairment of cooperative signalling from the 1,25-(OH)2D3-activated vitamin D receptor (VDR) and from the CaR in vitamin D and calcium insufficiency causes cellular dysfunction in many organs and biological systems, and, therefore, increases the risk of diseases, particularly of osteoporosis, colorectal and breast cancer, inflammatory bowel disease, insulin-dependent diabetes mellitus type I, metabolic syndrome, diabetes mellitus type II, hypertension and cardiovascular disease. Understanding the underlying molecular and cellular processes provides a rationale for advocating adequate intake of vitamin D and calcium in all populations, thereby preventing many chronic diseases worldwide.
Matti Narkia

Acid-base balance and bone - Acid-base balance, dentinogenesis and dental caries: Exper... - 0 views

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    Acid-base balance has an effect on bone turnover, especially on the rates of bone resorption and calcium mobilization. Bone mineral participates in the defense against acid-base disturbances, especially against metabolic acidosis (Lemann et al. 1966, Green & Kleeman 1991). The role of the bone mineral is important in the acid-base disorders, as no appreciable change in the intestinal calcium absorption occurs (Bichara et al. 1990). In the mammalian body, mainly three hormones regulate the calcium metabolism and the bone turnover. 1,25-dihydroxycholecalciferol (vitamin D derivative) increases calcium absorption from the intestine and, indirectly, from bone. Parathyroid hormone mobilizes calcium from the bone and increases the urinary phosphate excretion. Calcitonin inhibits bone resorption (Ganong 1981). Used as drugs, these hormones are also capable of inducing acid-base disorders. Calcitonin administration (Escanero et al. 1991) and vitamin D excess (Bichara et al. 1990) have been reported to cause metabolic alkalosis.
Matti Narkia

Effects of vitamin D and calcium supplementation on falls: a randomized controlled tria... - 0 views

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    Effects of vitamin D and calcium supplementation on falls: a randomized controlled trial. Bischoff HA, Stähelin HB, Dick W, Akos R, Knecht M, Salis C, Nebiker M, Theiler R, Pfeifer M, Begerow B, Lew RA, Conzelmann M. J Bone Miner Res. 2003 Feb;18(2):343-51. PMID: 12568412 A single intervention with vitamin D plus calcium over a 3-month period reduced the risk of falling by 49% compared with calcium alone. Over this short-term intervention, recurrent fallers seem to benefit most by the treatment. The impact of vitamin D on falls might be explained by the observed improvement in musculoskeletal function.
Matti Narkia

Calcium and vitamin D intakes may be positively associated with brain lesions in depres... - 0 views

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    Calcium and vitamin D intakes may be positively associated with brain lesions in depressed and nondepressed elders. Payne ME, Anderson JJ, Steffens DC. Nutr Res. 2008 May;28(5):285-92. PMID: 19083421 doi: 10.1016/j.nutres.2008.02.013 In conclusion, calcium and vitamin D consumption were associated with brain lesions in elderly subjects even after controlling for potentially explanatory variables. These associations may be due to vascular calcification or other mechanism. The possibility of adverse effects of high intakes of calcium and vitamin D needs to be further explored in longitudinal studies of elderly subjects.
Matti Narkia

The Effect of Vitamin D2 and Vitamin D3 on Intestinal Calcium Absorption in Nigerian Ch... - 0 views

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    The effect of vitamin D2 and vitamin D3 on intestinal calcium absorption in Nigerian children with rickets. Thacher TD, Obadofin MO, O'Brien KO, Abrams SA. J Clin Endocrinol Metab. 2009 Sep;94(9):3314-21. Epub 2009 Jun 30. PMID: 19567516 Conclusions: Despite similar increases in 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D with vitamin D2 or vitamin D3, fractional calcium absorption did not increase, indicating that rickets in Nigerian children is not primarily due to vitamin D-deficient calcium malabsorption
Matti Narkia

Vitamin D-dependent calcium-binding protein - Wikipedia, the free encyclopedia - 0 views

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    "Vitamin D-dependent calcium binding proteins were discovered in the cytosolic fractions of chicken intestine, and later in mammalian intestine and kidney, by workers including Robert Wasserman of Cornell University. They bound calcium in the micromolar range and were greatly reduced in vitamin D-deficient animals. Expression could be induced by treating these animals with vitamin D metabolites such as calcitriol. They were found to exist in two distant sizes with a molecular weight of approximately 9 kDa and 28 kDa. They were renamed calbindin; calbindin-D9k is found in mammalian intestine and calbindin-D28k in avain intestine and in kidney."
Matti Narkia

Calbindin - Wikipedia, the free encyclopedia - 0 views

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    "Calbindin describes calcium binding proteins first described as the vitamin D-dependent calcium binding proteins in intestine and kidney."
Matti Narkia

The Role of Vitamin D and Calcium in Type 2 Diabetes. A Systematic Review and Meta-Anal... - 0 views

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    The role of vitamin D and calcium in type 2 diabetes. A systematic review and meta-analysis. Pittas AG, Lau J, Hu FB, Dawson-Hughes B. J Clin Endocrinol Metab. 2007 Jun;92(6):2017-29. Epub 2007 Mar 27. Review. PMID: 17389701 .CONCLUSIONS: Vitamin D and calcium insufficiency may negatively influence glycemia, whereas combined supplementation with both nutrients may be beneficial in optimizing glucose metabolism.
Matti Narkia

NEJM -- Vitamin D3 and calcium to prevent hip fractures in the elderly women - 0 views

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    Vitamin D3 and calcium to prevent hip fractures in the elderly women. Chapuy MC, Arlot ME, Duboeuf F, Brun J, Crouzet B, Arnaud S, Delmas PD, Meunier PJ. N Engl J Med. 1992 Dec 3;327(23):1637-42. PMID: 1331788 CONCLUSIONS. Supplementation with vitamin D3 and calcium reduces the risk of hip fractures and other nonvertebral fractures among elderly women.
Matti Narkia

Calcium and vitamin d supplementation decreases incidence of stress fractures in female... - 0 views

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    Calcium and vitamin d supplementation decreases incidence of stress fractures in female navy recruits. Lappe J, Cullen D, Haynatzki G, Recker R, Ahlf R, Thompson K. J Bone Miner Res. 2008 May;23(5):741-9. PMID: 18433305 doi: 10.1359/jbmr.080102 Conclusions: Generalizing the findings to the population of 14,416 women who entered basic training at the Great Lakes during the 24 mo of recruitment, calcium and vitamin D supplementation for the entire cohort would have prevented 187 persons from fracturing. Such a decrease in SFx would be associated with a significant decrease in morbidity and financial costs.
Matti Narkia

A longitudinal study of serum 25-hydroxyvitamin D and intact parathyroid horm... - 0 views

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    A longitudinal study of serum 25-hydroxyvitamin D and intact parathyroid hormone levels indicate the importance of vitamin D and calcium homeostasis regulation in multiple sclerosis. Soilu-Hänninen M, Laaksonen M, Laitinen I, Erälinna JP, Lilius EM, Mononen I. J Neurol Neurosurg Psychiatry. 2008 Feb;79(2):152-7. Epub 2007 Jun 19. PMID: 17578859 doi:10.1136/jnnp.2006.105320 Conclusions: The endocrine circuitry regulating serum calcium may be altered in MS. There is an inverse relationship between serum vitamin D level and MS clinical activity. The role of vitamin D in MS must be explored further.
Matti Narkia

Dietary Reference Intakes for Vitamin D and Calcium - Institute of Medicine - 0 views

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    Dietary Reference Intakes for Vitamin D and Calcium An IOM committee has been named to undertake a study to assess current relevant data and update as appropriate the DRIs for vitamin D and calcium. The review will include consideration of chronic and non-chronic disease indicators. The study will also incorporate, as appropriate, systematic evidence-based reviews of the literature and an assessment of potential indicators of adequacy and of excess intake. Indicators for adequacy and excess will be selected based on the strength and quality of the evidence and the demonstrated public health significance, taking into consideration sources of uncertainty in the evidence.
Matti Narkia

Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride : Dietary Guidance : Food and N... - 0 views

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    This DRI report presents calcium, phosphorus, magnesium, vitamin D, and fluoride, all of which have key roles in developing and maintaining bone and other calcified tissues in the body. View or download the entire 454 page document or just selected sections below, or find information for obtaining the book version. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride (1997) National Academy of Sciences. Institute of Medicine. Food and Nutrition Board.
Matti Narkia

Animal Pharm: Hearts of Stone, Arteries of Glass - 0 views

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    A recent Wall Street Journal article "Defending Against Disease -- With Vitamin D New Studies Suggest It Isn't Just Bones That Might Benefit" by the wonderful Melinda Beck highlights benefits of Vitamin D3. In TYP, we've known the benefits for years :) but it's nice to see the rest of the world catching up. The benefits of Vitamin D3 are potent, powerful immunomodulation -- to the point where autoimmune diseases, viral and bacterial infections and cancer are effectively reduced. What is the value for heart disease and diabetes prevention? In hemodialysis patients, great lessons are can be learned. Nephrologists often describe patients with severe (stage 5) chronic kidney disease (CKD) patients on hemodialysis as having 'hearts of stone, blood vessels of glass.' Unfortunately over 70% of chronic hemodialysis patients have coronary artery disease (and Lp(a)). What medical science shows is that Agatston coronary calcification scores can be dramatically reduced when vitamin D is replenished and calcium is restricted. Sevelamer (Renagel) is a calcium-free, metal-free polymer phosphate binder. In 52-weeks, calcium restriction, a phosphate-binder and vitamin D resulted in one individual in a 21% reduction in Agatston CAC score (from 968 to 756; see Figure 2).
Matti Narkia

Dietary Acid-Base Balance, Bone Resorption, and Calcium Excretion -- Jajoo et al. 25 (3... - 0 views

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    Dietary acid-base balance, bone resorption, and calcium excretion. Jajoo R, Song L, Rasmussen H, Harris SS, Dawson-Hughes B. J Am Coll Nutr. 2006 Jun;25(3):224-30. PMID: 16766781 Conclusions: Diet changes that increase renal NAE are associated with increases in serum PTH, bone resorption, and calcium excretion over a 60-day period.
Matti Narkia

NEJM -- Calcium plus Vitamin D Supplementation and the Risk of Colorectal Cancer - 0 views

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    Calcium plus vitamin D supplementation and the risk of colorectal cancer. Wactawski-Wende J, Kotchen JM, Anderson GL, Assaf AR, Brunner RL, O'Sullivan MJ, Margolis KL, Ockene JK, Phillips L, Pottern L, Prentice RL, Robbins J, Rohan TE, Sarto GE, Sharma S, Stefanick ML, Van Horn L, Wallace RB, Whitlock E, Bassford T, Beresford SA, Black HR, Bonds DE, Brzyski RG, Caan B, Chlebowski RT, Cochrane B, Garland C, Gass M, Hays J, Heiss G, Hendrix SL, Howard BV, Hsia J, Hubbell FA, Jackson RD, Johnson KC, Judd H, Kooperberg CL, Kuller LH, LaCroix AZ, Lane DS, Langer RD, Lasser NL, Lewis CE, Limacher MC, Manson JE; Women's Health Initiative Investigators. N Engl J Med. 2006 Feb 16;354(7):684-96. Erratum in: N Engl J Med. 2006 Mar 9;354(10):1102. PMID: 16481636 Conclusions Daily supplementation of calcium with vitamin D for seven years had no effect on the incidence of colorectal cancer among postmenopausal women. The long latency associated with the development of colorectal cancer, along with the seven-year duration of the trial, may have contributed to this null finding. Ongoing follow-up will assess the longer-term effect of this intervention.
Matti Narkia

NEJM -- Vitamin D3 and calcium to prevent hip fractures in the elderly women - 0 views

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    Vitamin D3 and calcium to prevent hip fractures in the elderly women. Chapuy MC, Arlot ME, Duboeuf F, Brun J, Crouzet B, Arnaud S, Delmas PD, Meunier PJ. N Engl J Med. 1992 Dec 3;327(23):1637-42. PMID: 1331788 CONCLUSIONS. Supplementation with vitamin D3 and calcium reduces the risk of hip fractures and other nonvertebral fractures among elderly women.
Matti Narkia

Vitamin D and calcium supplementation reduces cancer risk: results of a randomized tria... - 0 views

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    Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. Lappe JM, Travers-Gustafson D, Davies KM, Recker RR, Heaney RP. Am J Clin Nutr. 2007 Jun;85(6):1586-91. Erratum in: Am J Clin Nutr. 2008 Mar;87(3):794. PMID: 17556697 Conclusions: Improving calcium and vitamin D nutritional status substantially reduces all-cancer risk in postmenopausal women.
Matti Narkia

New topics in vitamin D research - Google Books - 2 views

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    Table of Contents Ch. I Is calcidiol an active hormone? 1 Ch. II Vitamin D as a neurosteroid hormone : from neurobiological effects to behavior 29 Ch. III Inhibitors of vitamin D hydroxylases : mechanistic tools and therapeutic aspects 67 Ch. IV Vitamin D analogues as anti-cancer therapies 145 Ch. V Paricalcitol : a vitamin D2 analog with anticancer effects with low calcemic activity 169 Ch. VI Vitamin D use among older adults in U.S. : results form national surveys 1997 to 2002 181 Ch VII Vitamin D deficiency in migrants 199 Vitamin D is a fat-soluble steroid hormone precursor that contributes to the maintenance of normal levels of calcium and phosphorus in the bloodstream. Strictly speaking, it is not a vitamin since human skin can manufacture it, but it is referred to as one for historical reasons. It is often known as calciferol. The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones. It promotes bone mineralisation in concert with a number of other vitamins, minerals and hormones. Without vitamin D, bones can become thin, brittle, soft or misshapen. Vitamin D prevents rickets in children and osteomalacia in adults -- skeletal diseases that result in defects that weaken bones. This book gathers international research on the leading-edge of the scientific front.
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