Selenium is an essential mineral required in small amounts. This vital mineral was discovered in 1817 by Swedish chemist, Jons Berzelius. In 1957, Foltz and Schwartz established selenium as an essential trace element in nutrition for the prevention of disease. The human body selenium content is considered to be average 12-20 milligrams. Selenium is present in almost every cell in the body. However mostly, is found in the kidneys, liver, spleen, pancreas, thyroid, testes, and the lymph nodes.
Sources of High Selenium
Brewer’s yeast, Brazil nuts, wheat germ, butter, garlic, chives, sunflower seeds, raisins, eggs, whole grains, brown rice, lean meats, cheddar, mozzarella cheese, mustard seeds, mushrooms, halibut, mackerel, herring, smelts, tuna, cod, salmon, redsnapper, swordfish, flounder and shellfish selenium-containing foods. The level of selenium in plants depends on the soil in which they are grown. Selenium can be lost when food is processed or refined.
Requires selenium to create selenoproteins, enzymes important to human health. Selenoproteins are antioxidants that protect cells from free radical damage. Free radicals are by-products of oxidation and can occur during normal metabolism, can also be exposed to free radicals in smoke or other toxic exposures. Selenium is a vital component of the antioxidant enzyme known as glutathione peroxidase. Production of glutathione peroxidase for free radical scavenging depends upon the availability of selenium. (The level of blood selenium is determined by measuring the of this enzyme. Erythrocyte, serum and tissue levels of glutathione peroxidase can be measured to assess selenium rate. Selenium in hair and nails can also be measured). Glutathione peroxidase protects cell membranes from effect from free radicals released from hydrogen peroxide formed during normal metabolism in the cells mitochondria. Selenium and vitamin E have complementary however independent effects as antioxiadants in the protection of cells against the damaging effects of lipid peroxides and free radicals producedduring normal metabolism. Vitamin E and selenium work synergistically. Selenium when combined with vitamin E, it has demonstrated anti-inflammatory effect.
Selenium and Sulforaphane
Sulforaphane and selenium have also been shown to work synergistically protecting the body cells against damage caused by free radicals. Sulforaphane and other isothiocyanates have a chemical structure that makes them antioxidants. That is, although both selenium and sulforaphane have beneficial effects alone, when they are combined it is reported that their cancer fighting properties are increased thirteen fold. When combined, sulforaphane and selenium had a bigger impact on the genes than they did alone. The research in question is published in the journal “Carcinogenesis“.
Selenium, can help build up white blood cells, which boosts the body’s ability to fight illness and infection. Selenium supplementation in individuals who are not overtly selenium deficient appears to stimulate the immune response. Selenium supplementation was found to reduce the viral load in patients infected with human immunodeficiency virus (HIV). Selenium may increase resistance to HIV by enhancing the action of T-cells and modifying their production of cytokines. In a 2007 study conducted by the University of Miami; researchers observed that the selenium group reduces HIV viral load compared to the placebo group. In addition, selenium plays a role in reducing cellular stress and breakdown caused by the HIV virus. Selenium helps to produce antibodies, proteins in the blood and lymph that destroy bacteria, viruses and parasites that attack the body.also, selenium may stimulate the formation of antibodies in response to vaccines.
Often have low levels of selenium in cancer patients. A study published in the “American Journal of Epidemiology” measured serum selenium levels in over 9,000 Finns from 1968 to 1976. The research in question; revealed that those who previously had serum selenium amounts of less than 46 ng/ml were more likely to get lung cancer. Five-year study conducted at the the Cornell University and University of Arizona showed that consumption of 200 micrograms of selenium daily resulted in 63% fewer prostate tumors, 58% fewer colorectal cancers, 46% fewer lung malignancies, and a 39% overall decrease in cancer deaths. Selenomethionine is considered to be the best absorbed and utilized form of selenium. In one study of 1,312 people, those who took 200 mcg of selenium per day had 2/3 lower risk of developing prostate cancer during the 4.5-year study compared to those who took a placebo. In a 1997 study published in Biomedical and Environmental Sciences, supplements of 200 mcg of selenium a day were shown to lower the risk of mortality from prostate, colorectal and lung cancers. Researches indicates that the methylated forms of selenium are the active species against tumors, and these methylated selenium compounds are produced at the greatest amounts with excess selenium intakes. A study conducted at “Harvard University“; found that men with high selenium levels have a 65 % lower chance of getting prostate cancer and recommends 159 micrograms of the mineral for the protective effect. Study results published in 2004 in the Journal of the National Cancer Institute found that people with the highest blood levels of selenium had a 34 % lower risk of abnormal cell growth and developing new polyps in the rectum and colon. Anticancer mechanism of selenium; 1-As anti-oxidant, can help protect the body from harmful effects of free radicals. 2- improving immune system function. 3-increasing the levels of selenium metabolites that inhibit tumor cell growth. 4-Affecting the metabolism of carcinogens. 5- Selenium has been shown to induce DNA repair and synthesis in damaged cells, to inhibit the proliferation of cancer cells, and to induce their apoptosis.
Selenium is a critical mineral for maintaining healthy function of the thyroid gland. Is a necessary component of three enzymes that contribute to thyroid hormone production and your thyroid contains more selenium than any other tissue in your body. (Selenium is needed in the conversion of the thyroid hormone T4 into its active version, T3). In order for the thyroid to produce the most active form of its hormone, selenium is not only essential, also helps regulate the amount of hormone that is produced. Selenium and iodine work together to convert the inactive hormone T4 into active T3 to circulate properly in your bloodstream and signal different cellular functions. In addition, selenium may have the ability to suppress anti-thyroid antibodies for persons who suffer from thyroid inflammation or thyroiditis.
Selenium increases fertility in men by enhancing sperm production and sperm movement. Blood selenium amounts have been found to be lower in men with low sperm counts. A young and healthy man produces more than four million sperm per hour in each testicle. Selenium acts to help prevent oxidation of the sperm cell, aiding in maintaining sperm cell integrity. Research has shown that selenium improves the health of Leydig cells inside testes. This has the beneficial effect of improving sperm quality. In one Scottish study; (96 men), received either a composite tablet containing selenium and vitamins and minerals or a placebo tablet to be taken daily for a period of three months. The sperm quality was recorded before and after the study. Showed that the motility of sperm cells in the treatment groups had increased by as much as 80 % but when the men stopped taking the tablet, their sperm cell quality was seen to fall again. (To produce improvement in sperm quality, a daily intake of 130 mcg per day is required.) In another study, 500 infertile men took 200 micrograms of selenium per day, 600 mg of NAC (N-acetyl-cysteine) per day, these two nutrients combined or a placebo. After 26 weeks, men who had taken NAC and selenium together had more sperm with normal structure and form, more balanced levels of a group of hormones that regulate and control the number of sperm, more concentrated sperm counts and better sperm movement. (“Journal of Urology,” date of publication 2008)
•Selenium-amino acid chelates
•Sodium selenite and sodium selenate
Selenium yeast and selenomethionine are an organic form of selenium. Inorganic forms of selenium are sodium selenite, and sodium selenate. Inorganic forms are not absorbed as organic forms. Selenite has about a 50 % absorption level. Selenate is almost completely absorbed. Selenate is almost completely absorbed. But, a significant amount is excreted in the urine before it can be used by the body’s protein. In one study, selenium levels in red blood cells of people receiving selenomethionine increased by 100% after 16 weeks supplementation. Neither selenate nor selenite produced significant increases under the same conditions.
Maximum Daily Dose of Selenium
The RDA for Selenium is 55-70 micrograms (mcg), and recommendations include 100-200 micrograms. Dosage should not exceed 400 micrograms per day. The doses used in experimental studies; To strengthen the immune system 100 mcg. Infection 100 mcg. To prevent cancer; 200 mcg, colon cancer 200 mcg. HIV 400 mcg.
Selenium Toxicity Symptoms
Nausea, vomiting, diarrhea, nail changes, hair loss, skin lesions, facial flushing, garlic breath, muscle cramps, joint pain and loss of energy. Selenium supplements should not be taken with anticoagulant medications or medications that slow the blood-clotting process. This mineral is also; may interact with other medicines, such as, chemotherapy drugs, corticosteroids, statin drugs, birth control pills and antacids.