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vitamin D supplements

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49 papers 0 to 25 followers Studies about vitamin d supplementation and effective doses.
By Clare Dix Dietitian, PhD candidate, researching vitamin D and obesity
Yvonne Pasing, Christopher Graham Fenton, Rolf Jorde, Ruth Hracky Paulssen
Vitamin D is hydroxylated in the liver and kidneys to its active form, which can bind to the vitamin D receptor (VDR). The VDR is present in a wide variety of different cells types and tissues and acts as a transcription factor. Although activation of the VDR is estimated to regulate expression of up to 5% of the human genome, our study is the first analysing gene expression after supplementation in more than 10 subjects. Subjects of a randomized controlled trial (RCT) received either vitamin D3 (n=47) in a weekly dose of 20,000 IU or placebo (n=47) for a period of three to five years...
October 2017: Journal of Steroid Biochemistry and Molecular Biology
A Arabi, N Khoueiry-Zgheib, Z Awada, R Mahfouz, L Al-Shaar, M Hoteit, M Rahme, R Baddoura, G Halabi, R Singh, G El Hajj Fuleihan
We studied the association between CYP2R1 genetic polymorphisms and circulating 25-hydroxyvitamin D [25(OH)D] before and after supplementation with vitamin D3 in 218 elderly. We found differences between 3 and 8 ng/ml in circulating levels at baseline in women but not in the response after 1 year of supplementation. INTRODUCTION: This study evaluated the association between polymorphisms in four single nucleotide polymorphisms (SNPs) of the CYP2R1 gene and 25(OH)D levels before and 1 year after supplementation with two different doses of vitamin D3 (600 IU daily or a dose equivalent to 3750 IU daily), in a cohort of 218 (96 men and 122 women) Lebanese elderly overweight subjects...
January 2017: Osteoporosis International
S Salekzamani, H Mehralizadeh, A Ghezel, Y Salekzamani, M A Jafarabadi, A S Bavil, B P Gargari
PURPOSE: The evidence in support of the effect of vitamin D deficiency on cardiovascular diseases is inconsistent. The objective of this randomized, controlled, double-blind study was to assess the effect of high-dose vitamin D supplementation on cardiometabolic risk factors in subjects with metabolic syndrome. METHODS: Eighty subjects were randomized to receive 50,000 IU vitamin D or matching placebo weekly for 16 weeks. Fasting blood sugar, homeostasis model assessment of insulin resistance, insulin sensitivity (Quicki), serum lipid profiles (low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride (TG) and total cholesterol), anthropometric factors and blood pressure were assessed before and after intervention...
November 2016: Journal of Endocrinological Investigation
Rene F Chun, Ivan Hernandez, Renata Pereira, Leon Swinkles, Tonnie Huijs, Rui Zhou, Nancy Q Liu, Albert Shieh, Miriam Guemes, Sanjay M Mallya, John S Adams, Martin Hewison
25-Hydroxyvitamin D (25D) circulates bound primarily to serum vitamin D binding protein (DBP), with DBP showing higher binding affinity for 25D3 than 25D2. We therefore hypothesized that vitamin D2 (D2) promotes higher serum levels of unbound 25D (free 25D), with different functional responses, relative to vitamin D3 (D3). Week 3 C56BL/6 mice were placed on diets containing either D2 or D3 alone (both 1000 IU/kg). At week 8 and week 16, D2 mice had only 25D2 in circulation (26.6 ± 1.9 and 33.3 ± 4.4 ng/mL), and D3 mice had only 25D3 (28...
September 2016: Endocrinology
Heike Annette Bischoff-Ferrari, Bess Dawson-Hughes, Elisabeth Stöcklin, Eduard Sidelnikov, Walter Churchill Willett, John Orav Edel, Hannes Balthasar Stähelin, Swen Wolfram, Alexander Jetter, Joseph Schwager, Jana Henschkowski, Arnold von Eckardstein, Andreas Egli
To test the effect of 25(OH)D(3) (HyD) compared to vitamin D(3) on serum 25-hydroxyvitamin D levels (25(OH)D), lower extremity function, blood pressure, and markers of innate immunity. Twenty healthy postmenopausal women with an average 25(OH)D level of 13.2 ± 3.9 ng/mL (mean ± SD) and a mean age of 61.5 ± 7.2 years were randomized to either 20 µg of HyD or 20 µg (800 IU) of vitamin D(3) per day in a double-blind manner. We measured on 14 visits over 4 months, 25(OH)D serum levels, blood pressure, and seven markers of innate immunity (eotaxin, interleukin [IL]-8, IL-12, interferon gamma-induced protein 10 kDa [IP-10], monocyte chemotactic protein-1 [MCP-1], macrophage inflammatory protein beta [MIP-1β], and "Regulated upon Activation, Normal T-cell Expressed, and Secreted" [RANTES])...
January 2012: Journal of Bone and Mineral Research: the Official Journal of the American Society for Bone and Mineral Research
Sue A Shapses, Deeptha Sukumar, Stephen H Schneider, Yvette Schlussel, Robert M Sherrell, M Paul Field, Hasina Ambia-Sobhan
BACKGROUND: Weight loss (WL) is associated with a decrease in calcium absorption and may be one mechanism that induces bone loss with weight reduction. OBJECTIVE: Because vitamin D supplementation has been shown to increase true fractional calcium absorption (TFCA), the goal of this study was to examine the effect of vitamin D during WL or weight maintenance (WM). DESIGN: A randomized, placebo-controlled, double-blind 6-wk study was conducted in 82 postmenopausal women [BMI (in kg/m(2); ±SD): 30...
March 2013: American Journal of Clinical Nutrition
Laura Tripkovic, Helen Lambert, Kathryn Hart, Colin P Smith, Giselda Bucca, Simon Penson, Gemma Chope, Elina Hyppönen, Jacqueline Berry, Reinhold Vieth, Susan Lanham-New
BACKGROUND: Currently, there is a lack of clarity in the literature as to whether there is a definitive difference between the effects of vitamins D2 and D3 in the raising of serum 25-hydroxyvitamin D [25(OH)D]. OBJECTIVE: The objective of this article was to report a systematic review and meta-analysis of randomized controlled trials (RCTs) that have directly compared the effects of vitamin D2 and vitamin D3 on serum 25(OH)D concentrations in humans. DESIGN: The ISI Web of Knowledge (January 1966 to July 2011) database was searched electronically for all relevant studies in adults that directly compared vitamin D3 with vitamin D2...
June 2012: American Journal of Clinical Nutrition
Bess Dawson-Hughes, Susan S Harris, Nancy J Palermo, Lisa Ceglia, Helen Rasmussen
It is sometimes assumed that dietary fat is required for vitamin D absorption, although the impact of different amounts of dietary fat on vitamin D absorption is not established. This study was conducted to determine whether the presence of a meal and the fat content of the meal influences vitamin D absorption or the 25-hydroxyvitamin D [25(OH)D] response to supplemental vitamin D3 . Based on earlier studies in rats we postulated that absorption would be greatest in the low-fat meal group. Sixty-two healthy older men and women were randomly assigned to one of three meal groups: no meal, high-fat meal, or low-fat meal; each was given a monthly 50,000 IU vitamin D3 supplement with the test breakfast meal (or after a fast for the no-meal group) and followed for 90 days...
August 2013: Journal of Bone and Mineral Research: the Official Journal of the American Society for Bone and Mineral Research
Arash Hossein-nezhad, Michael F Holick
PURPOSE OF REVIEW: Vitamin D has received global attention because of its many health benefits. Although there is general agreement about the importance of vitamin D for bone health, there remains skepticism about the nonskeletal health benefits of vitamin D. This review will not only focus on the vitamin D deficiency pandemic and ways to treat and prevent vitamin D deficiency but will also explore the epigenetic mechanisms of vitamin D that could help explain many of the nonskeletal benefits of enhancing vitamin D status...
November 2012: Current Opinion in Clinical Nutrition and Metabolic Care
Ghada El-Hajj Fuleihan, Roger Bouillon, Bart Clarke, Marlene Chakhtoura, Cyrus Cooper, Michael McClung, Ravinder J Singh
Hypovitaminosis D is prevalent worldwide but proportions vary widely between regions, depending on genetic and lifestyle factors, the threshold to define deficiency, and accuracy of 25-hydroxyvitamin D (25OHD) assays used. Latitude, pollution, concealing clothing, sun exposure, gender, dietary habits, and lack of government regulation account for up to 50% in variations in serum 25OHD levels, whereas genetic polymorphisms in the vitamin D pathway account for less than 5%. Organizations/societies have developed guidelines for recommended desirable 25OHD levels and vitamin D doses to reach them, but their applicability across age groups and populations are still debated...
July 2015: Journal of Bone and Mineral Research: the Official Journal of the American Society for Bone and Mineral Research
Laura Plante, Louis-Nicolas Veilleux, Francis H Glorieux, Hope Weiler, Frank Rauch
Osteogenesis imperfecta (OI) is a heritable condition characterized by fragile bones. Our previous studies indicated that serum 25-hydroxyvitamin D (25OHD) concentrations were positively associated with lumbar spine areal bone mineral density (LS-aBMD) in children and adolescents with OI. Here we assessed whether one year of high-dose vitamin D supplementation results in higher LS-aBMD z-scores in youth with OI. A one-year double-blind randomized controlled trial conducted at a pediatric orthopedic hospital in Montreal, Canada...
May 2016: Bone
Yasaman Motlaghzadeh, Fatemeh Sayarifard, Bahar Allahverdi, Ali Rabbani, Aria Setoodeh, Azadeh Sayarifard, Farzaneh Abbasi, Mohammad-Taghi Haghi-Ashtiani, Abbas Rahimi-Froushani
BACKGROUND: Obesity seems to be a critical issue nowadays because of its high prevalence and its adverse effects on health. There is some evidence indicating the relationship between obesity and lower serum 25-hydroxyvitamin D [25(OH)D] concentration. The aim of the present study was to examine serum 25(OH)D status of obese and non-obese Iranian children and compare their therapeutic response with identical oral vitamin D3 treatment. METHODS: In a non-randomized clinical trial, serum 25(OH)D level of 45 obese and 45 non-obese Iranian children aged 2-14 years was measured...
August 2016: Journal of Tropical Pediatrics
Paul J Veugelers, Truong-Minh Pham, John Paul Ekwaru
The Recommended Dietary Allowance (RDA) is the nutrient intake considered to be sufficient to meet the requirements of 97.5% of the population. Recent reports revealed a statistical error in the calculation of the RDA for vitamin D opening the question of what the recommendation should be. We took a dual approach to answer this question: (1) we aggregated 108 published estimates on vitamin D supplementation and vitamin D status; and (2) we analyzed 13,987 observations of program participants. The aggregation of published data revealed that 2909 IU of vitamin D per day is needed to achieve serum 25-hydroxyvitamin D (25(OH)D) concentrations of 50 nmol/L or more in 97...
December 4, 2015: Nutrients
Paul Glendenning, Charles A Inderjeeth
A dramatic and sustained surge in vitamin D test numbers has been attributed to the extraskeletal and probable intra/paracrine effects of vitamin D and not the important role of vitamin D in the regulation of extracellular calcium homeostasis and bone metabolism. This review summarizes recent data regarding the skeletal and extraskeletal effects of vitamin D, provides an overview of current methods of 25-hydroxyvitamin D measurement and includes the beneficial and adverse effects of vitamin D replacement. The role of 1,25-dihydroxyvitamin D, 24,25-dihydroxyvitamin D, vitamin D binding protein and free hormone levels are explored and potential future developments in this area are discussed...
2016: Critical Reviews in Clinical Laboratory Sciences
Mohammad Shafi Kuchay, Ganesh Sudhakar Jevalikar, Ambrish Mithal, Sunil Kumar Mishra, Navin Dang
BACKGROUND: This study aimed to evaluate the efficacy and safety of a single monthly dose of cholecalciferol in healthy school children. METHODS: A total of 118 children of class VI of a residential school were selected to receive vitamin D supplementation in the form of oral cholecalciferol 60,000 IU monthly. Serum calcium and 25-hydroxyvitamin D (25OHD) levels were estimated at 0 and 12 months. The proportion of subjects achieving vitamin D sufficiency was assessed...
April 2016: Journal of Pediatric Endocrinology & Metabolism: JPEM
Nasser M Al-Daghri, Omar S Al-Attas, Soundararajan Krishnaswamy, Sobhy M Yakout, Abdul Khader Mohammed, Amal M Alenad, George P Chrousos, Majed S Alokail
Parathyroid hormone (PTH) plays a crucial role in calcium metabolism and skeletal development via altering vitamin D level. Besides, hypersecretion of PTH is implicated in the etiology of osteoporosis. In this study, we analyzed association between promoter region sequence variants of PTH gene and circulating 25-hydroxy-vitamin D (25(OH)D) level. Genotypes of PTH SNPs rs1459015, rs10500783 and rs10500784 and circulating serum 25(OH)D level of healthy adults (N=386) of different nationalities living in Riyadh were determined and relation between the different PTH allelic variants and corresponding mean 25(OH)D values were obtained using Analysis of Variance (ANOVA) and Bonferroni post-hoc test for multiple comparisons...
2015: International Journal of Clinical and Experimental Pathology
Nazanin Moslehi, Sakineh Shab-Bidar, Parvin Mirmiran, Farhad Hosseinpanah, Fereidoun Azizi
This systematic review aimed to assess the determinants of the parathyroid hormone (PTH) level response to vitamin D supplementation. We searched Medline, Google Scholar and the reference lists of previous reviews. All randomised controlled trials (RCT) on vitamin D supplementation that involved apparently healthy human subjects with a report of PTH were selected. Potential studies were screened independently and in duplicate. Results are summarised as mean differences with 95% confidence intervals. Quality assessment, subgroup analysis, meta-analysis and meta-regression analysis were carried out...
November 14, 2015: British Journal of Nutrition
C T Sempos, R A Durazo-Arvizu, N Binkley, J Jones, J M Merkel, G D Carter
Unstandardized laboratory measurement of 25-hydroxyvitamin D (25(OH)D) confounds efforts to develop clinical and public health vitamin D guidelines. The Vitamin D Standardization Program (VDSP), an international collaborative effort, was founded in 2010 to correct this problem. Nearly all published vitamin D research is based on unstandardized laboratory 25(OH)D measurements. While it is impossible to standardize all old data, it may be possible to identify a small subset of prior studies critical to guidelines development...
November 2016: Journal of Steroid Biochemistry and Molecular Biology
Kevin D Cashman, Kirsten G Dowling, Zuzana Škrabáková, Mairead Kiely, Christel Lamberg-Allardt, Ramon A Durazo-Arvizu, Christopher T Sempos, Seppo Koskinen, Annamari Lundqvist, Jouko Sundvall, Allan Linneberg, Betina Thuesen, Lise Lotte N Husemoen, Haakon E Meyer, Kristin Holvik, Ida M Grønborg, Inge Tetens, Rikke Andersen
Knowledge about the distributions of serum 25-hydroxyvitamin D (25(OH)D) concentrations in representative population samples is critical for the quantification of vitamin D deficiency as well as for setting dietary reference values and food-based strategies for its prevention. Such data for the European Union are of variable quality making it difficult to estimate the prevalence of vitamin D deficiency across member states. As a consequence of the widespread, method-related differences in measurements of serum 25(OH)D concentrations, the Vitamin D Standardization Program (VDSP) developed protocols for standardizing existing serum 25(OH)D data from national surveys around the world...
November 2015: Scandinavian Journal of Clinical and Laboratory Investigation
Ian R Reid
The classical clinical consequence of vitamin D deficiency is osteomalacia, presenting as rickets in children. This remains a common problem in parts of the Middle East and the Indian subcontinent, and occurs when serum 25-hydroxyvitamin D levels are <25 nmol/L. Osteomalacia remains the only problem that is unequivocally a consequence of vitamin D deficiency. Low levels of 25-hydroxyvitamin D are observed in a wide range of conditions, but consistent trial evidence of amelioration of these conditions with vitamin D is lacking...
February 2016: Archives of Disease in Childhood
2015-07-27 11:12:30
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