| This
trace mineral functions primarily as a component of the antioxidant
enzyme, glutathione peroxidase. Glutathione peroxidase activity, which
requires selenium for activity, facilitates the recycling of vitamins
C and vitamin E in optimizing the performance of the antioxidant system.
Low levels of selenium have been linked to higher risk for cancer,
cardiovascular disease, and other conditions associated with free
radical damage, including aging and cataract formation. Selenium is
also essential for healthy cell-mediated immune function, stimulating
immune properties of lymphocytes. Selenium is also needed for the
activation of thyroid hormones.
Chronic low selenium intake is associated with an increased risk
for heart disease, cancer and depressed immune function. Selenium
appears to provide protection against heart disease and stroke.
Selenium supplementation (110 ugm/daily) increases the ratio of
HDL to LDL and inhibits platelet aggregation.
Selenium and glutathione peroxidase activity are low in patients
with rheumatoid arthritis, eczema, psoriasis and most inflammatory
conditions. This is related to the increased synthesis of pro-inflammatory
prostagladins and leukotriens. Immune system function is enhanced
by selenium, by contributing to higher natural killer cell (NKC)
activity. Natural killer cells have a the ability to destroy cancer
cells and bacterial and viral agents. Heavy metal toxicity symptoms
may be alleviated by selenium, acting as an antagonist. Selenium
deficiency may also contribute to male infertility.
Selenium is safe at the level generally used for supplementation
(100-200 mcg/day). However, taking more than 750 mcg of selenium
per day may cause toxicity with reactions such as loss of fingernails,
skin rash and neurological aberrations. In the presence of iodine
deficiency goiter, selenium supplementation has been reported to
exacerbate low thyroid function.
Selenium is
available in several different forms. Studies indicate that inorganic
salts like sodium selenite are less effectively absorbed and not
as biologically active forms of selenium, such as selenomethionine
or high-selenium content yeast. Highest sources of dietary selenium
are found in wheat germ, brazil nuts, whole wheat bread, brown rice,
bran red swiss chard, oats, turnips.
|
hCG
