Posted by Larry Hoover on January 1, 2004, at 14:56:50
In reply to Re: really worried about past selenium use » Larry Hoover, posted by headachequeen on January 1, 2004, at 13:35:16
> taking more than 25 mcg is excessive really
No it is not. Please refer to the most authoritative review of the subject I have ever seen:
http://books.nap.edu/books/0309069351/html/284.html#pagetop> It binds toxic metals such as mercury and cadmium, flsuhing them from the system, and works with iodine to enhance and unhealthy thyroid function...
It binds mercury, but does not flush it from the body. It stabilizes the mercury so that it can do no more harm, but the mercury remains in your tissues until death releases it. One of the most intense point-source anthropogenic (man-made) mercury emissions comes from crematoriums. Some of the mercury is from amalgam dental work, but the rest arises from tissue stores.
> but in most of North America it is best taken with medical supervision or direction as it comes in questionable dosages and can do harm as much as it does good...
That is a very misleading statement. The Lowest Observeable Adverse Effects Level (LOAEL) is 900 mcg/day, chronic ingestion. Individuals in the most seleniforous region of the United States, in Wyoming, consume in excess of 400 mcg/day seleniuum, with no adverse effects. The highest intake was estimated at about 800 mcg/day, with no adverse effect on health.
> This is not a trace mineral to be playing with on one's own wick... we tend to read things in books on vitamins and so on and jump in and diagnose ourselves or treat ourselves and this is not the thing to do
I recognize that caution is advised. But my recommendations are cautious.
> especially when trying to deal with side effects of a medication as this board was discussing...
....which can be ameliorated by mineral supplements.
> when the supplement in question will do nothing to help it... and might, especially when taken in large amounts do harm ...
...I'm not advocating large amounts. There is nothing at all large about 200 mcg/day selenium.
Moreover, following your suggestion, I researched any link between selenium and reproductive health, and found that selenium deficiency is associated with low sperm motility. I found no evidence for a toxic effect from excessive selenium ingestion.
Selenium supplementation (in excess of the requirement for stabilization of plasma glutathione peroxidase concentrations) is associated with a reduction in cancer risk, and with mood enhancement.
Here's a review article that clearly states that supplementation of 100-200 mcg/day selenium is necessary for the cancer-protective effects. There are numerous selenium supplementation trials underway right now, testing the effect on a variety of differenct cancers.
Mutat Res. 2001 Apr 18;475(1-2):123-39.
The protective role of selenium on genetic damage and on cancer.El-Bayoumy K.
Division of Cancer Etiology and Prevention, American Health Foundation, 1 Dana Road, 10595, Valhalla, NY, USA. kelbayoumy@aol.com
Collectively, results from epidemiologic studies, laboratory bioassays, and human clinical intervention trials clearly support a protective role of selenium against cancer development. Several hypotheses have been proposed to explain these observations. Increased genomic instability, either inherent or induced by exogenous agents (mutagens or carcinogens), has been considered as a primary event leading to neoplastic transformation. This report deals specifically with the evidence for a role of selenium in the inhibition of carcinogen-induced covalent DNA adduct formation and retardation of oxidative damage to DNA, lipids and proteins, and for modulating cellular and molecular events that are critical in cell growth inhibition and in the multi-step carcinogenesis process. At present, the bulk of our knowledge on the role of selenium on genetic stability is based primarily on animal data and from studies conducted in in vitro systems. Studies performed in vitro showed that the dose and form of selenium compounds are critical factors with regard to cellular responses. Inorganic (at doses up to 10microM) and organic selenium compounds (at doses equal to or greater than 10microM) elicit distinctly different cellular responses. The recommended daily allowance (RDA) is 50-70 microgramSe per day for healthy adults; with 40 microgramSe as minimum requirement. Less than 11 microgramSe will definitely put people at risk of deficiency that would be expected to cause genetic damage. Daily doses of 100-200 microgramSe inhibited genetic damage and cancer development in humans. About 400 microgramSe per day is considered an upper limit. Clearly, doses above the RDA are needed to inhibit genetic damage and cancer. However, it has been hypothesized that the intake of excessive doses of selenium may cause oxidative damage, leading to genomic instability. The use of a cocktail consisting of selenium, and other vitamins and minerals appears to be a promising approach to inhibit genetic damage and the development of cancer. It is the author's recommendation that development of mechanism-based hypotheses that can be tested in pilot studies in different populations prior to a large-scale clinical trial in humans, is of paramount importance in order to better understand the role of selenium on genetic stability and cancer.
Here are a couple references for mood effects of selenium supps:Biol Psychiatry. 1991 Jun 1;29(11):1092-8.
The impact of selenium supplementation on mood.
Benton D, Cook R.
Department of Psychology, University College, Swansea, Wales, UK.
The possibility that a subclinical deficiency of the trace element selenium might exist in a sample of the British population was examined by giving a selenium supplement for 5 weeks. Using a double-blind cross-over design, 50 subjects received either a placebo or 100 mcg selenium on a daily basis. On three occasions they filled in the Profile of Moods States. A food frequency questionnaire was used to estimate the intake of selenium in the diet. Intake was associated with a general elevation of mood and in particular, a decrease in anxiety. The change in mood when taking the active tablet was correlated with the level of selenium in the diet, which was estimated from a food frequency questionnaire. The lower the level of selenium in the diet the more reports of anxiety, depression, and tiredness, decreased following 5 weeks of selenium therapy. The results are discussed in terms of the low level of selenium in the food chain in some parts of the world.
Nutr Neurosci. 2002 Dec;5(6):363-74.Selenium intake, mood and other aspects of psychological functioning.
Benton D.
Department of Psychology, University of Wales Swansea, Swansea SA2 8PP, Wales, UK. d.benton@swansea.ac.uk
Selenium is an essential trace element although the level of selenium in food items reflects the soil in which they were grown and thus varies markedly between different parts of the world. The metabolism of selenium by the brain differs from other organs in that at times of deficiency the brain retains selenium to a greater extent. The preferential retention of selenium in the brain suggests that it plays important functions. To date mood is the clearest example of an aspect of psychological functioning that is modified by selenium intake. Five studies have reported that a low selenium intake was associated with poorer mood. The underlying mechanism is unclear although a response to supplementation was found with doses greater than those needed to produce maximal activity of the selenoprotein glutathione peroxidase. Although the functions of many selenoproteins are unknown some play important roles in anti-oxidant mechanisms. As there are suggestions that oxidative injury plays a role in normal aging, schizophrenia, Parkinson's and Alzheimer's disease, the possible role of selenium is considered. Although there is evidence that supplementation with anti-oxidant vitamins shown some promise with Alzheimer's patients, and in preventing the development of tardive dyskinesia in schizophrenics taking neuroleptics, a role for selenium has been little considered.
poster:Larry Hoover
thread:50878
URL: http://www.dr-bob.org/babble/20031231/msgs/295426.html