Food Study: Selenium
 

Selenium

http://www.lef.org/protocols/metabol...ulation_01.htm
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Selenium. Selenium is required for appropriate thyroid hormone synthesis, activation, and metabolism. Adequate selenium supports efficient thyroid hormone synthesis and metabolism and protects the thyroid gland from damage caused by excessive exposure to iodide (Zimmerman MB 2002). Long-term selenium deficiency in experimental animal models led to thyroid cell death and scarring after high iodide loads (Kohrle J 1999). Selenium deficiency may seriously influence the generation of free radicals, the conversion of thyroxineT4 to T3, and the autoimmune process (Kohrle J 1999).
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Dietary Recommendations

Some foods contain goiterogenic substances that prevent the utilization of iodine. These foods include canola oil, Brassica vegetables (e.g., cabbage, Brussels sprouts, broccoli, and cauliflower), corn, cassava, sweet potatoes, lima beans, and pearl millet. The actual content of goitrogens in these foods is quite low, however, and cooking destroys it.
Hypothyroid patients should also avoid soy supplements (Bell DS et al 2001; Jabbar MA et al 2001).

http://www.lef.org/protocols/cancer/colorectal_03.htm
Selenium is an essential trace element found in vegetables, cereals, grains, and nuts. Selenium reduces the incidence of colorectal cancer (Finley JW 2006), at least in part by increasing antioxidant levels that protect against cancer initiation (Peters U et al. 2006b); Wallace K et al 2003; Fleet JC 1997).
High selenium levels are associated with restoration of glutathione peroxidase levels (Ip C et al 1991), proper functioning of immune system cells, and a reduced occurrence of colorectal adenomas (Connelly-Frost A et al. 2006; Peters U et al. 2006a); Ferencik M et al 2003). By contrast, selenium deficiency increases susceptibility to colorectal cancer (Davis CD et al 2003; Kowal M et al 2003) and is associated with high levels of the tumor marker CA 19-9 (Lasch K et al 1999). Patients prone to colon adenomas and those with colon cancer have significantly lower selenium levels (less than 70 micrograms per liter (µg/L) (Fernandez-Banares F et al 2002; Milde D et al 2001; Psathakis D et al 1998).
In a double-blind, placebo-controlled trial, patients with colon adenomas presented with low serum levels of selenium before treatment, but supplemental selenium normalized their selenium levels (Al-Taie OH et al 2003). Reduced activity of this selenium-dependent enzyme is associated with increased risk and poor prognosis in colorectal cancer patients (Milde D et al 2001). In a double-blind, three-year intervention study of polyp-bearing patients, selenium (101 mcg) protected against the formation of new adenomas (Hofstad B et al 1998). A phase III clinical trial is investigating selenium to see how well it works in preventing the recurrence of polyps in patients with adenomatous colorectal polyps (for more information, visitwww.clinicaltrials.gov).
Brazil nuts, plant foods, tuna, cod, and eggs contain high levels of selenium.