Posts Tagged ‘Selenium’

Study: The impact of common micronutrient deficiencies on iodine and thyroid metabolism: the evidence from human studies.

Thursday, September 22nd, 2011

-:: This Abstract is posted here for posterity and archival purposes only ::-

Best Pract Res Clin Endocrinol Metab. 2010 Feb;24(1):117-32.
The impact of common micronutrient deficiencies on iodine and thyroid metabolism: the evidence from human studies.
Hess SY.

Program in International and Community Nutrition, Department of Nutrition, University of California, Davis, CA, USA. syhess@ucdavis.edu
Abstract

Deficiencies of micronutrients are highly prevalent in low-income countries. Inadequate intake of iodine impairs thyroid function and results in a spectrum of disorders. Other common deficiencies of micronutrients such as iron, selenium, vitamin A, and possibly zinc may interact with iodine nutrition and thyroid function. Randomised controlled intervention trials in iodine- and iron-deficient populations have shown that providing iron along with iodine results in greater improvements in thyroid function and volume than providing iodine alone. Vitamin A supplementation given alone or in combination with iodised salt can have a beneficial impact on thyroid function and thyroid size. Despite numerous studies of the effect of selenium on iodine and thyroid metabolism in animals, most published randomised controlled intervention trials in human populations failed to confirm an impact of selenium supplementation on thyroid metabolism. Little evidence is available on interactions between iodine and zinc metabolism.

Copyright 2009 Elsevier Ltd. All rights reserved.

PMID:
20172476
[PubMed - indexed for MEDLINE]
From http://www.ncbi.nlm.nih.gov/pubmed/20172476

Selenium and the control of thyroid hormone metabolism.

Friday, July 1st, 2011

-:: This Abstract is posted here for posterity and archival purposes only ::-

Thyroid. 2005 Aug;15(8):841-53.
Selenium and the control of thyroid hormone metabolism.
Köhrle J.

Institut für Experimentelle Endokrinologie und Endokrinologisches Forschungs-Centrum der Charité EnForCé, Charité Universitätsmedizin Berlin, Berlin, Germany. josef.koehrle@charite.de

Abstract

Thyroid hormone synthesis, metabolism and action require adequate availability of the essential trace elements iodine and selenium, which affect homeostasis of thyroid hormone-dependent metabolic pathways.

The three selenocysteine-containing iodothyronine deiodinases constitute a novel gene family. Selenium is retained and deiodinase expression is maintained at almost normal levels in the thyroid gland, the brain and several other endocrine tissues during selenium deficiency, thus guaranteeing adequate local and systemic levels of the active thyroid hormone T(3).

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Due to their low tissue concentrations and their mRNA SECIS elements deiodinases rank high in the cellular and tissue-specific hierarchy of selenium distribution among various selenoproteins.

While systemic selenium status and expression of abundant selenoproteins (glutathione peroxidase or selenoprotein P) is already impaired in patients with cancer, disturbed gastrointestinal resorption, unbalanced nutrition or patients requiring intensive care treatment, selenium-dependent deiodinase function might still be adequate.

However, disease-associated alterations in proinflammatory cytokines, growth factors, hormones and pharmaceuticals modulate deiodinase isoenzyme expression independent from altered selenium status and might thus pretend causal relationships between systemic selenium status and altered thyroid hormone metabolism.

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Study: Effects of combined iodine and selenium deficiency on thyroid hormone metabolism in rats

Friday, July 1st, 2011

-:: This Abstract is posted here for posterity and archival purposes only ::-

Am J Clin Nutr. 1993 Feb;57(2 Suppl):240S-243S.

Effects of combined iodine and selenium deficiency on thyroid hormone metabolism in rats.

Beckett GJ, Nicol F, Rae PW, Beech S, Guo Y, Arthur JR.

University Department of Clinical Chemistry, Royal Infirmary, Edinburgh, UK.

Abstract

This paper compares the effects of combined iodine and selenium deficiency, of single deficiencies of these trace elements, and of no deficiency on thyroid hormone metabolism in rats.

In rats deficient in both trace elements, thyroidal triiodothyronine (T3), thyroidal thyroxin (T4), thyroidal total iodine, hepatic T4, and plasma T4 were significantly lower, and plasma thyroid-stimulating hormone (TSH) and thyroid weight were significantly higher than in rats deficient in iodine alone.

Plasma and hepatic T3 concentrations were similar in the dietary groups. Hepatic type I iodothyronine deiodinase (ID-I) activity was inhibited by selenium deficiency irrespective of the iodine status. Type II deiodinase (ID-II) activity in the brain was significantly higher and in pituitary, significantly lower in combined deficiency than in iodine deficiency alone.

These data show that selenium can play an important role in determining the severity of the hypothyroidism associated with iodine deficiency.

PMID:
8427196
[PubMed - indexed for MEDLINE]
Source: http://www.ncbi.nlm.nih.gov/pubmed/8427196

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Study: The impact of iron and selenium deficiencies on iodine and thyroid metabolism: biochemistry and relevance to public health.

Friday, July 1st, 2011

-:: This Abstract is posted here for posterity and archival purposes only ::-

Thyroid. 2002 Oct;12(10):867-78.

The impact of iron and selenium deficiencies on iodine and thyroid metabolism: biochemistry and relevance to public health.

Zimmermann MB, Köhrle J.

Laboratory for Human Nutrition, Swiss Federal Institute of Technology, Zürich, Switzerland. Michael.zimmermann@ilw.agrt.ethz.ch
Abstract

Several minerals and trace elements are essential for normal thyroid hormone metabolism, e.g., iodine, iron, selenium, and zinc. Coexisting deficiencies of these elements can impair thyroid function.

Iron deficiency impairs thyroid hormone synthesis by reducing activity of heme-dependent thyroid peroxidase. Iron-deficiency anemia blunts and iron supplementation improves the efficacy of iodine supplementation.

Combined selenium and iodine deficiency leads to myxedematous cretinism. The normal thyroid gland retains high selenium concentrations even under conditions of inadequate selenium supply and expresses many of the known selenocysteine-containing proteins. Among these selenoproteins are the glutathione peroxidase, deiodinase, and thioredoxine reductase families of enzymes.

Adequate selenium nutrition supports efficient thyroid hormone synthesis and metabolism and protects the thyroid gland from damage by excessive iodide exposure.

In regions of combined severe iodine and selenium deficiency, normalization of iodine supply is mandatory before initiation of selenium supplementation in order to prevent hypothyroidism.

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Trace elements content and hormonal profiles in women with androgenetic alopecia

Thursday, May 12th, 2011

J Trace Elem Med Biol. 2010 Dec 15.
Trace elements content and hormonal profiles in women with androgenetic alopecia.
Skalnaya MG, Tkachev VP.

Russian Society of Trace Elements in Medicine, Zemlyanoy Val str., 46, Moscow 105064, Russia; ANO “Centre for Biotic Medicine”, Zemlyanoy Val str., 46, Moscow 105064, Russia.

It is well-known that some trace element imbalances play a significant role in the pathomechanism of many forms of alopecia. Androgenetic alopecia, however, is a specific local sensitivity of hair follicle receptors to androgens.

In a clinical and laboratory study, 153 women with androgenetic alopecia (AGA) and 32 control women were examined. In AGA patients telogen hair and vellus hair (miniaturization, D<30μm) significantly differed in frontal and parietal hair comparison with occipital area (20±0.9% vs. 12±0.5% and 33±0.9% vs. 12±0.6% respectively).

In the AGA group levels of androstenedione and dihydrotestosterone were higher than in the control group. Hair elemental content, analyzed by ICP-MS, demonstrated a lowered Cu and Zn content in the frontal area in comparison to the occipital area. It is important to note, that the AGA patients with elevated levels of androstenedione and dihydrotestosterone presented an increased Cu content and decreased Mn, Se, Zn contents in the occipital area of scalp. The occipital level of Cu positively correlated with the concentration of free testosterone in the serum.

A negative correlation between the Zn content in the occipital area and the dehydroepiandrosterone level in the blood was found.

Unfortunately, a routine treatment course of AGA patients, including topical inhibitor of 5-alpha-reductase and minoxidil, had no effect on the Cu hair content in occipital and frontal areas.

However, there were positive changes in the morphological structure and other trace element contents. These data led us to hypothesize a key role of Cu metabolism disturbances in the AGA onset, development of AGA, and potential pharmaceutical targets for the treatment of AGA.

Heavy Metal Detox Supplements

Monday, January 31st, 2011

I’ve heard of a few good ways to chelate and cleanse the body of toxic heavy metals.

Here’s a list of the heavy metal chelating methods available:

  • OSR (oxidative stress relief)
  • Humifulvate
  • Toxguard
  • Modified Citrus Pectin / MCP / Sodium Alginate
  • ALA – alpha lipoic acid – lipoic acid
  • R-ALA – R alpha lipoic acid
  • Detoxamin
  • EDTA – ethylenediamine tetraacetic acid
  • Magnesium
  • Iodine
  • Silica Hydride
  • Chlorella – algae
  • Bentonite clay and Activated charcoal
  • MMS
  • Zeolites
  • Cilantro
  • DMPS – dimercaptopropane sulfonate sodium
  • Brazil Nuts
  • DMSA – dimercaptosuccinic acid
  • DMSO
  • Spirulina
  • Standard process catalyn and zinc liver chelate
  • Waiora’s NCD – natural cellular defense
  • Oral chelation/longevity plus
  • Dental mercury detox by sam and michael ziff
  • Selenium
  • Sulforaphane
  • garlic, sprouted broccoli seeds, anything that supports the liver, etc..

My favorites include Cilantro, Iodine, Chlorella, selenium, modified citrus pectin (MCP), and Humifulvate amongst others.

Some sources:

Enzymatic Therapy, Complete Metal Cleanse, 30 UltraCaps from iHerb or from Swanson’s: http://www.swansonvitamins.com/ET415/ItemDetail?n=0

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About Selenium

Sunday, January 16th, 2011

Selenium and Methylselenocysteine

Selenium is an essential trace mineral that is essential for life. It is also a toxic metal when consumed in excess. Selenium is required to activate various key enzymes, including the antioxidant glutathione peroxidase, the metabolic enzyme thioredoxin reductase, and the thyroid-hormone-activating enzyme iodothyronine deiodinase. Food sources of selenium include brazil nuts, yeast, whole grains and seafood. Selenium content of food is dependent on selenium content in the soil and both are highly variable.
Selenium: The Anticancer Mineral

Epidemological studies recognized a connection between cancer incidence and low levels of selenium in the blood as early as 1969. Researchers noted that breast cancer rates were low in areas where selenium levels in the soil and food were high and high in areas where selenium levels were low. The same correlation was found between death rates and selenium levels. Similar correlations were subsequently found in animal studies.
Helps in treatment and prevention of dandruff. Necessary for healthy hair and nails. May also increase the elastic youthfulness of the skin and be helpful in removing age spots. When ingested in the natural algae form of selenomethionine, skin cancer incidence from ultraviolet light may also be reduced.
Selenium (Se) is an essential trace element that functions as a component of enzymes involved in antioxidant protection and thyroid hormone metabolism. In several intra- and extra-cellular glutathione peroxidases, iodothyronine 5н-deiodinases, and in thioredoxin reductase, selenium is located at the active centers as the selenoamino acid, selenocysteine (SeCYS). At least two other proteins of unknown function also contain SeCYS. Although SeCYS is an important dietary form, it is not directly incorporated into these specific selenium-proteins; instead, a co-translational process yields tRNA-bound SeCYS. In contrast, selenium as seleno-methionine is incorporated non-specifically into many proteins, as it competes with methionine in general protein synthesis. Therefore, tissues often contain both specific, as well as the nonspecific, selenium-containing proteins when both SeCYS and selenomethionine are consumed, as found in many foods.

IMPORTANCE: A major antioxidant nutrient, protects cell membranes and prevents free radical generation thereby decreasing the risk of cancer and disease of the heart and blood vessels. Medical surveys show that increased selenium intake decreases the risk of breast, colon, lung and prostate cancer. Selenium also preserves tissue elasticity; slows down the aging and hardening of tissues through oxidation; helps in the treatment and prevention of dandruff.

Deficiencies: Selenium deprivation reduces activities of the selenium-dependent enzymes. The signs in animals depend upon vitamin E status and appear only when both nutrients are limiting. They vary according to species. For example, selenium- and vitamin E-deficient animals show myopathies of skeletal (e.g., sheep, cow, horse), cardiac (pig) or smooth (dog, cow) muscle; hepatic necrosis (rat, pig); increased capillary permeability (chicken); or pancreatic acinar degeneration (chicken). Characteristic signs of selenium deficiency have not been described in humans, but very low selenium status is a factor in the etiologies of a juvenile cardiomyopathy (Keshan Disease) and a chondrodystrophy (Kashin-Beck Disease) that occur in selenium-deficient regions of China. May result in premature aging, heart disease, dandruff, loose skin.

Diet recommendations: The Recommended Dietary Allowances are in µg/day: 0-0.5 yrs, 10; 0.5-1.0 yrs, 15; 1-6 yrs, 20; 7-10 yrs, 30; males 11-14 yrs, 40; females 11-14 yrs, 45; males and females 15-18 yrs, 50; adult males, 70; adult females, 55; pregnancy, 65; and lactation, 75.

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Selenium Supplements

Thursday, January 6th, 2011

I have used these products:

Selenium Synergy – Jarrow
Selenium 100 mcg yeast free form  mineral supplement L-selenomethionine

Now, I am switching to “L-Se-methylselenocysteine” AKA SeMSC sold by Swansons:

Swanson Ultra SeMSC Selenium http://www.swansonvitamins.com/SWU171/ItemDetail?n=0
* Delivers all-around antioxidant protection
* A natural, high-bioavailability selenium/amino acid complex
* Supports cardiovascular, prostate and immune system health and more

Get one of the most effective selenium supplements available today! The same form of selenium found in garlic, broccoli and Brussels sprouts, SeMSC is a natural, high-bioavailability selenium/amino acid complex with unique protective benefits for colon and breast health.



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