Learn More About Selenium
What is selenium?
Selenium is one of the essential trace minerals in the human body. This nutrient comprises an important part of the antioxidant enzymes that protect cells against the effects of free radicals produced during normal oxygen metabolism. The body has developed defenses such as selenium-containing antioxidants to control levels of toxic free radical that damage cells and contribute to the development of some chronic diseases. The immune system and thyroid gland also require selenium for normal functioning.
What are food sources of selenium?
Good food sources of selenium are brazil nuts and organ meats and seafood, as well as muscle meats such as beef heart. An important consideration is that plants do not require selenium for their own growth and health, and so the amount of this trace nutrient they contain depends solely on how much selenium happens to be in the local soil. Some areas, such as the Southeastern United States, tend be have low selenium levels, sometimes making food sources problematic. Parts of China have so little selenium in the soil that table salt must be fortified with selenium as a public health measure.
What is selenium used for?
Not only have geographic studies consistently observed higher cancer mortality rates in populations living in areas with low soil selenium and relatively low dietary selenium intakes, but more than two-thirds of over 100 published studies in 20 different animal models of spontaneous, viral, and chemically induced cancers have found that selenium supplementation significantly reduces tumor incidence. Observations such as these have created a great deal of interest in whether or not selenium might help to lower cancer risk in people, and indeed, a number of studies seem to bear this possibility out.
For example, one American double-blind, placebo-controlled study of 1,300 older adults found that supplementation with 200 mcg/day of selenium-enriched yeast for an average of 7.4 years was associated with a 49% decrease in prostate cancer incidence in men. And in Dr. Larry Clark’s study at the University of Arizona, a modest dose of selenium reduced overall cancer incidence by a remarkable 42 percent.
But selenium’s role in health does not appear to be related to cancer prevention alone. Studies in Denmark, Finland, and elsewhere strongly suggest a correlation between high intake of selenium and reduced risk of various types of cardiovascular disease, including stroke, myoccardial infarction (heart attack), and buildup of arterial plaque. And again, geographical observation indicates a higher risk of stroke for those people who live in areas that have low levels of selenium in the soil.
While one study found a significant increase in illness and death from cardiovascular disease in individuals with serum selenium levels below 45 mcg/liter compared to matched pairs above 45 mcg/liter (42), another study, using the same cutoff points for serum selenium, found a significant difference only in deaths from stroke (43). One study in middle-aged and elderly Danish men found an increased risk of cardiovascular disease in men with serum selenium levels below 79 mcg/liter (44), but several other studies found no clear inverse association between selenium nutritional status and cardiovascular disease risk (45). In a multi-center study in Europe, toenail selenium levels and risk of myocardial infarction (heart attack) were only associated in the center where selenium levels were the lowest.
Also, low levels of plasma selenium have also been associated with a significantly increased risk of complications from HIV. One randomized control trial in 186 HIV-positive men and women found that selenium supplementation at 200 mcg/day for two years significantly decreased hospitalization rates .
Selenium—or the lack thereof—may even play a role in the course that influenza infection takes. Some mouse studies suggest that insufficient selenium can cause the flu virus to mutate into a more dangerous form, and lead to lung inflammation and possibly pneumonia.
Surveys of patients with rheumatoid arthritis, a chronic disease that causes pain, stiffness, swelling, and loss of function in joints, have indicated that they have reduced selenium levels in their blood. In addition, some individuals with arthritis have a low selenium intake.
How is selenium taken?
Many nutritionally-minded doctors and researchers suggest taking approximately 200 mcg per day of selenium. Some recommend a yeast-based form of selenium, although non-yeast versions are available for those with allergies. The cost of such a regimen is low, only a few cents a day.
The Recommend Daily Allowance of selenium for most people is 55 mcg per day. (Note: Do not confuse mcg with mg!)
Is selenium safe?
Selenium appears to be compatible with most medications, and may even enhance the efficacy of certain chemotherapy agents such as taxol and adriamycin.
Do not take more than a few hundred micrograms of selenium per day unless you are under a doctor’s supervision, as higher amounts may lead to a serious but reversible form of selenium overdose called selenosis.
And remember, you can obtain the best selling selenium supplements from A1Supplements.com at the lowest prices!
© A1Supplements.com 2008.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.