subject: Importance of selenium supplementation as a trace elements for prevention of many life threatining diseases [print this page] Importance of selenium supplementation as a trace elements for prevention of many life threatining diseases
One of the main activities of this mineral is its anti-aging properties and its ability to help rid the body of free radicals, as well as toxic minerals such as mercury, lead and cadmium.
It is helpful in fighting infections since it stimulates increased antibody response to infections, promotes more energy in the body, and while it helps with alleviating menopausal symptoms in women, it assists the male in producing healthy sperm.
In certain cases selenium has also proven effective in helping to fight cold sores and shingles, which are both caused by the herpes virus.
Some researchers have shown that in selenium-deficient animals a harmless virus can mutate into a virulent form capable of causing damage and death - this has also been followed up with other studies, which seem to indicate that selenium helps to keep the spread and multiplying of viruses in check.
Selenium is also used against arthritis and multiple sclerosis and if provided in adequate amounts it is thought to help prevent cancer as well. Tissue elasticity and pancreatic function is also dependant on this mineral.
In a study it was shown that selenium could be useful in treating certain cancers, and is also helpful in making the blood less "sticky", which is helpful in preventing heart attacks and strokes.
The dosage is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
In the case of microelements, such as trace elements, the amounts are very small, yet they are still important and 70 micrograms per day is taken as the required dosage.
Toxicity and symptoms of high intake:-
selenium is toxic and too large quantities may result in hair loss, tooth decay, brittle nails, white spots, poor appetite, sour taste in the mouth, loss of feeling in the hands and feet, change in skin pigmentation and the breath may have a garlic smell.
Best used with:-
Selenium should always be taken with vitamins E, A and beta-carotene, and it is preferable when taking a supplement to take selenium in the form of selenocysteine or selenomethionine, which are both organic.
People with yeast intolerance should check the source of the selenium used in the supplement, as certain manufacturers obtain selenium from yeast.
Men need more selenium than women as it is lost in the seminal fluid, and people staying in areas where the soil is poor in selenium, should also pay attention to their selenium intake.
When can selenium deficiency occur ?
Selenium deficiency is most commonly seen in parts of China where the selenium content in the soil, and therefore selenium intake, is very low. Selenium deficiency is linked to Keshan Disease. The most common signs of selenium deficiency seen in Keshan Disease are an enlarged heart and poor heart function. Keshan disease has been observed in low-selenium areas of China, where dietary intake is less than 19 mcg per day for men and less than 13 mcg per day for women. This intake is significantly lower than the current RDA for selenium.
Selenium deficiency also may affect thyroid function because selenium is essential for the synthesis of active thyroid hormone. Researchers also believe selenium deficiency may worsen the effects of iodine deficiency on thyroid function, and that adequate selenium nutritional status may help protect against some of the neurological effects of iodine deficiency.
Selenium deficiency has been seen in people who rely on total parenteral nutrition (TPN) as their sole source of nutrition. TPN is a method of feeding nutrients through an intravenous (IV) line to people whose digestive systems do not function. Forms of nutrients that do not require digestion are dissolved in liquid and infused through the IV line. It is important for TPN solutions to provide selenium in order to prevent a deficiency. Physicians can monitor the selenium status of individuals receiving TPN to make sure they are receiving adequate amounts.
Severe gastrointestinal disorders may decrease the absorption of selenium, resulting in selenium depletion or deficiency. Gastrointestinal problems that impair selenium absorption usually affect absorption of other nutrients as well, and require routine monitoring of nutritional status so that physicians can recommend appropriate treatment.
Who may need extra selenium ?
Selenium supplementation is essential for anyone relying on TPN as the sole source of nutrition, and selenium supplementation has become routine during TPN administration since the relationship between selenium deficiency and TPN was discovered. Gastrointestinal disorders such as Crohn's disease can impair selenium absorption. Most cases of selenium depletion or deficiency are associated with severe gastrointestinal problems, such as in individuals who have had over half of their small intestines surgically removed. A physician, who will determine the need for selenium supplementation, should evaluate individuals who have gastrointestinal disease and depleted blood levels of selenium.
What are some current issues and controversies about selenium ?
Selenium and cancer
Some studies indicate that mortality (death) from cancer, including lung, colorectal, and prostate cancers, is lower among people with higher selenium blood levels or intake. Also, the incidence of non-melanoma skin cancer is significantly higher in areas of the United States with low soil selenium levels.
The effect of selenium supplementation on the recurrence of these types of skin cancers was studied in seven dermatology clinics in the US from 1983 through the early 1990s. Supplementation with 200 mcg selenium daily did not affect recurrence of skin cancer, but significantly reduced total mortality and mortality from cancers. In addition, incidence of prostate cancer, colorectal cancer, and lung cancer was lower in the group given selenium supplements.
However, not all studies have shown a relationship between selenium status and cancer. In 1982, over 60,000 participants of the Nurses Health Study with no history of cancer submitted toenail clippings for selenium analysis. Toenail analysis is thought to reflect selenium status over the previous year. After three and one-half years, researchers compared the toenail selenium levels of nurses with and without cancer. They did not find any apparent benefit of higher selenium levels .
These conflicting results emphasize the need for additional research on the relationship between selenium and chronic diseases such as cancer. A study that may help answer some of the questions about the effect of selenium supplementation on cancer risk has started in France. The vitamins and antioxidant minerals supplementation, or SU.VI.MAX Study, is a prevention trial that is providing doses of antioxidant vitamins and minerals that are one to three times higher than recommended intakes, including a daily supplement of 100 mcg selenium. More than 12,000 men and women are being followed for eight years to determine the effect of supplementation on the incidence of chronic disease, such as cancers and cardiovascular disease.
Selenium and heart disease
Some population surveys have indicated an association between a lower antioxidant intake with a greater incidence of heart disease. Additional lines of evidence suggest that oxidative stress from free radicals may promote heart disease. For example, it is the oxidized form of low-density lipoproteins (LDL, often called "bad" cholesterol) that promotes plaque build-up in coronary arteries. Selenium is one of a group of antioxidants that may help limit the oxidation of LDL cholesterol and thereby help to prevent coronary artery disease. Currently there is insufficient evidence available to recommend selenium supplements for the prevention of coronary heart disease.
Selenium and arthritis
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.
The body's immune system naturally makes free radicals that can help destroy invading organisms and damaged tissue, but that can also harm healthy tissue. Selenium, as an antioxidant, may help control levels of free radicals and help to relieve symptoms of arthritis. Current findings are considered preliminary, and further research is needed before selenium supplements can be recommended for individuals with arthritis.
Selenium and HIV
HIV / AIDS related malabsorption can deplete levels of many nutrients. Selenium deficiency is commonly associated with HIV / AIDS, and has been associated with a high risk of death from this disease. Of 24 children with HIV who were observed for five years, those with low selenium levels died at a younger age, which may indicate faster disease progression. An examination of 125 HIV positive men and women also associated selenium deficiency with mortality. Researchers believe that selenium may be important in HIV disease because of its role in the immune system and as
an antioxidant. Selenium also may be needed for the replication of the HIV virus, which could deplete host levels of selenium. Researchers are actively investigating the role of selenium in HIV / AIDS, and see a need for clinical trials that evaluate the effect of selenium supplementation on HIV disease progression.
What is the health risk of too much selenium ?
There is a moderate to high health risk of too much selenium. High blood levels of selenium can result in a condition called selenosis. Symptoms include gastrointestinal upsets, hair loss, white blotchy nails, and mild nerve damage. Selenium toxicity is rare in the United States and the few reported cases have been associated with industrial accidents and a manufacturing error that led to an excessively high dose of selenium in a supplement. The Institute of Medicine has set a tolerable upper intake level for selenium at 400 micrograms per day for adults to prevent the risk of developing selenosis. "Tolerable upper intake levels represent the maximum intake of a nutrient that is likely to pose no risk of adverse health effects in almost al individuals in the general population".
