Vitamins

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Yvonne
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Re: Vitamins

Post by Yvonne » Sun 2 May 2010 11:51

http://www.ncbi.nlm.nih.gov/pmc/article ... ool=pubmed

Vitamin D and molecular actions on the immune system: modulation of innate and autoimmunity
Abstract

Vitamin D has received increased attention recently for its pleiotropic actions on many chronic diseases. The importance of vitamin D on the regulation of cells of the immune system has gained increased appreciation over the past decade with the discovery of the vitamin D receptor (VDR) and key vitamin D metabolizing enzymes expressed by cells of the immune system. Animal studies, early epidemiologic and clinical studies have supported a potential role for vitamin D in maintaining immune system balance. The hormonal form of vitamin D up-regulates anti-microbial peptides, namely cathelicidin, to enhance clearance of bacteria at various barrier sites and in immune cells. Vitamin D modulates the adaptive immune system by direct effects on T cell activation and on the phenotype and function of antigen-presenting cells (APCs), particularly of DCs. The purpose of this manuscript is to review the molecular and clinical evidence for vitamin D as a modulator of the innate and adaptive immune system.
Conclusions

Innate and adaptive immune balance

Potent immunomodulatory activities of vitamin D on both innate and adaptive immune responses have been recently discovered [12, 22, 25, 99, 107–114]. While innate immunity is enhanced against “high-affinity” foreign antigens, vitamin D sufficiency has a dampening effect on the processing of “low-affinity” self antigens. Although the precise mechanisms are still being discovered, the important role of vitamin D in maintaining immune homeostasis should not be overlooked. Interventional studies to further define the immunomodulatory effects of vitamin D in humans need to be done.
In summary, the effects of 1,25(OH)2D on the immune system include decreasing Th1/Th17 CD4+ T cells and cytokines, increasing regulatory T cells, downregulation of T cell-driven IgG production and inhibition of dendritic cell differentiation. While enhancing protective innate immune responses, 1,25(OH)2D helps maintain self-tolerance by dampening overly zealous adaptive immune responses [115].
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Yvonne
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Re: Vitamins

Post by Yvonne » Tue 22 Jun 2010 9:24

What lies behind the vitamin D revolution? :

http://www.cortlandtforum.com/what-lies ... le/165306/
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Yvonne
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Re: Vitamins

Post by Yvonne » Tue 22 Jun 2010 9:26

http://www.medicalnewstoday.com/articles/191487.php

Genome-Wide Study Identifies Factors That May Affect Vitamin D Levels
An international research consortium has identified four common gene variants that are associated with blood levels of vitamin D and with an increased risk of vitamin D deficiency. The report from the SUNLIGHT consortium - involving investigators from six countries - will appear in The Lancet and is receiving early online release.

"We identified four common variants that contributed to the risk for vitamin D deficiency," says Thomas Wang, MD, of the Massachusetts General Hospital (MGH) Heart Center, a co-corresponding author of the Lancet report. "Individuals inheriting several of these risk-associated variants had more than twice the risk of vitamin D deficiency as was seen in those without these variants."

Vitamin D's essential role in musculoskeletal health is well known, and in recent years epidemiologic evidence has suggested that vitamin D deficiency may contribute to conditions like diabetes, cardiovascular disease and some cancers. Naturally produced in the skin in response to sunlight, Vitamin D has been added to many types of food and is available in dietary supplements. But studies have shown that from one third to one half of healthy adults in developed countries have low levels of vitamin D. While reduced sun exposure is clearly associated with lower vitamin D levels, environmental and cultural factors - including dietary intake - cannot completely account for variations in vitamin levels. The fact that vitamin D status tends to cluster in families suggests a genetic contribution

The SUNLIGHT (Study of Underlying Genetic Determinants of Vitamin D and Highly Related Traits) Consortium involved a research team from the U.S., U.K., Canada, Netherlands, Sweden and Finland who pooled data from 15 epidemiologic studies of almost 32,000 white individuals of European descent. Results of the comprehensive genetic screening were correlated with participants' serum vitamin D levels. Statistically significant associations were found for four common variants, all in genes coding enzymes involved with the synthesis, breakdown or transport of vitamin D. The risk association was independent of geographic or other environmental factors; and the more variants an individual inherited, the greater the risk of vitamin D deficiency.

"It's possible that these results could explain why some people respond well to vitamin D supplements and others don't, but that needs to be studied further since we didn't specifically examine response to supplementation," Wang explains. "We also need to investigate how genetic background can modify response to sunlight, whether these associations are seen in other populations, and if these gene variants have an impact in the chronic diseases that appear to be associated with vitamin D deficiency
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Yvonne
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Re: Vitamins

Post by Yvonne » Tue 22 Jun 2010 9:27

What Is Vitamin D Deficiency? Mixed Messages About Sun Exposure :

http://www.medicalnewstoday.com/articles/191407.php
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Re: Vitamins

Post by Yvonne » Tue 22 Jun 2010 9:28

Osteoporos Int. 2010 Jun 17. [Epub ahead of print]

Are commonly recommended dosages for vitamin D supplementation too low? Vitamin D status and effects of supplementation on serum 25-hydroxyvitamin D levels-an observational study during clinical practice conditions.

Leidig-Bruckner G, Roth HJ, Bruckner T, Lorenz A, Raue F, Frank-Raue K.

Gemeinschaftspraxis für Endokrinologie, Nuklearmedizin und Humangenetik, Brückenstr. 21, 69120, Heidelberg, Germany, thomas.bruckner@t-online.de.

Abstract
Vitamin D deficiency is associated with increased fracture risk. The observational study aimed to investigate vitamin D status and supplementation in ambulatory patients. Only 20% of patients had optimal serum 25-hydroxyvitamin D [25(OH)D] levels. Commonly recommended dosages were insufficient to achieve clinically relevant increase of 25(OH)D levels. Higher dosages were safe and effective under clinical practice conditions. INTRODUCTION: Vitamin D deficiency is associated with adverse health outcome. The study aimed to investigate vitamin D status and supplementation in ambulatory patients. METHODS: Nine hundred seventy-five women and 188 men were evaluated for bone status from January 2008 to August 2008 within an observational study; 104 patients (n = 70 osteoporosis) received follow-up after 3 months. Dosage of vitamin D supplementation was documented and serum 25(OH)D and parathyroid hormone (PTH) determined. RESULTS: In all patients (age, 60.4 +/- 14.1 years), distribution of 25(OH)D was 56.3 +/- 22.3 nmol/L (normal range, 52-182 nmol/L) and PTH 53.8 +/- 67.5 ng/L (normal range, 11-43 ng/L). The proportion of patients with 25(OH)D < 25, 25 to <50, 50 to <75, >/=75 nmol/L was 7.5%, 33.3%, 38.9% and 20.2% in the total group and 20.1%, 38.5%, 30.8%, 10.6% at baseline in the follow-up group, respectively. After 3 months, 3.9% had still 25(OH)D < 25 nmol/L; only 12.5% achieved 25(OH)D >/= 75 nmol/L. In osteoporosis patients, 25(OH)D increased more in those taking >/=1,500 (median, 3,000) IU vitamin D per day (33.1 +/- 14.7 nmol/L) compared with </=1,000 (median, 800) IU/day (10.6 +/- 20.0 nmol/L) (p < 0.0008). PTH decreased more in patients taking >/=1,500 IU/day (-13.2 +/- 15.2 ng/L) compared with </=1,000 IU/day (-7.6 +/- 19.2 ng/L; p = 0.29). 25(OH)D was negatively correlated to PTH (r = -0.49, p < 0.0001). An increase of 25(OH)D >/= 75 nmol/L resulted in normalised PTH. CONCLUSION: Supplementation with higher vitamin D dosages (2,000-3,000 IU/day) is required to achieve a relevant increase of 25(OH)D and normalisation of PTH.

PMID: 20556359
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Yvonne
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Re: Vitamins

Post by Yvonne » Tue 22 Jun 2010 9:28

Hautarzt. 2010 Jun;61(6):478, 480-6.

The significance of vitamin D metabolism in human skin. An update

[Article in German]

Trémezaygues L, Reichrath J.

Klinik für Dermatologie, Venerologie und Allergologie, Hautklinik und Poliklinik, Universitätsklinikum des Saarlandes, 66421, Homburg/Saar, Germany. lea-louisa.tremezaygues@uks.eu

Abstract
Vitamin D deficiency is endemic, affecting worldwide approximately more than 1 billion people and approximately 60% of the German population. In recent years, our understanding of the important role of vitamin D for human health has grown enormously. Epidemiological and in vitro investigations as well as animal studies have convincingly demonstrated new important functions of vitamin D, including potent immunoregulatory and growth regulatory properties. We know today that vitamin D deficiency/insufficiency is not exclusively associated with an increased risk for bone diseases, but with a multitude of other diseases (including various types of cancer, cardiovascular diseases, infectious diseases, and autoimmune diseases). We discuss our present understanding of the importance of the cutaneous vitamin D system.

PMID: 20502851
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Yvonne
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Re: Vitamins

Post by Yvonne » Tue 22 Jun 2010 9:32

Confirmation That Vitamin D Deficiency Common Across A Range Of Rheumatic Conditions :

http://www.medicalnewstoday.com/articles/192311.php
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Re: Vitamins

Post by Yvonne » Thu 24 Jun 2010 16:44

http://www.medicalnewstoday.com/articles/192325.php

Predicting An Individual's Vitamin D Needs
Your skin tone and the amount of sunshine you receive--in addition to what foods you eat--can all influence the amount of vitamin D that your body has on hand for optimum health. In a preliminary and apparently first-of-its-kind study, Agricultural Research Service (ARS) research physiologist Charles B. Stephensen and colleagues have developed a preliminary model that predicts an individual's vitamin D requirements.

Stephensen is based at the ARS Western Human Nutrition Research Center at the University of California-Davis.

Scientists have known since the early 20th century that our bodies are stimulated to make vitamin D when ultraviolet rays from the sun reach our skin. But the amount of direct sunlight that a person receives is affected not only by the amount of time spent in the sun, but also by latitude, season, skin pigmentation, and even the amount of protective clothing that one wears.

Some vitamin D comes from food, including salmon and some other fish; milk and breakfast cereals fortified with this essential nutrient, and nutritional supplements such as multivitamin tablets.

The current recommended daily allowance of vitamin D for U.S. adults who are less than 50 years of age is 200 international units.

To develop the preliminary model, Stephensen and co-investigators worked with 72 young adult volunteers who provided intermittent records of what they ate and, for 7- to 8-week stints, wore photosensitive badges from 7 a.m. to 7 p.m. so scientists could determine their level of sun exposure.

Data from the volunteers--either African-American or of European ancestry--who had relatively low amounts of sun exposure suggest that they may need additional vitamin D to reach a target blood level of 75 nanomoles of vitamin D per liter of plasma.

Stephensen cautions, however, that some vitamin D levels indicated by the model exceed the level currently considered safe. More research, with a larger number of volunteers, may refine the predictive power of the model, he reports.

The research was published earlier this year in the Journal of Nutrition
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Yvonne
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Re: Vitamins

Post by Yvonne » Sun 4 Jul 2010 16:18

Low Vitamin D Linked To The Metabolic Syndrome In Elderly People :

http://www.medicalnewstoday.com/articles/193594.php
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Re: Vitamins

Post by Yvonne » Thu 8 Jul 2010 9:54

Duodecim. 2010;126(10):1127-34.

[Human anti-infectious defence may be enhanced by vitamin D]

[Article in Finnish]

Alitalo A.

HUSLAB, Kliininen Mikrobiologia, HUS.

Abstract
Findings about the significance of vitamin D for intrinsic immune defense may explain the effects of sunlight on immunity. Beyond the skin and the mucus layer of mucosae, antimicrobial peptides constitute the first-line defence, acting very rapidly. Their synthesis is dependent on vitamin D. Certain antimicrobial peptides inhibit the function of influenza virus. The most important factor affecting vitamin D production is sunlight, whereby the levels of this vitamin exhibit seasonal variation. Risk groups should pay special attention to the supply of vitamin D particularly during the winter infection season.

PMID: 20597342
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