This trace mineral is essential to many body functions and can be found in every body cell, but especially in the kidneys, liver, spleen, pancreas, and testes. In males, approximately half of the body’s selenium concentrates in the testicles and parts of the seminal ducts around the prostate gland.
In fact, selenium and vitamin E, another powerful antioxidant, are synergists, meaning they each improve the efficiency of the other.
Some studies indicate that selenium can be useful in the treatment of acne, while other research indicates that it may be useful in repairing chromosome damage. It may counteract heavy metals and other contaminants that find their way into the body. Selenium may also help in the prevention of undesired and dangerous blood clots.
The amount of selenium provided by plant sources depends a great deal on the soil quality in which the plants were grown. Poor soil will yield plants that may not provide the correct levels of selenium. Those who follow a vegetarian diet, particularly a vegan diet, must be extremely vigilant in making sure they consume enough selenium in their daily diets.
Sources of selenium
Some natural sources of selenium are Brazil nuts, garlic, fish, red meat, and grains.
Other sources of selenium are Lobster, tuna, shrimp, oysters, herring, liver, egg, ham, beef, bacon, chicken, lamb, veal, oats, brown rice, garlic, broccoli, wheat germ, whole grains, mushrooms, red grapes, and sesame seeds.
Benefits of selenium
The trace mineral selenium functions primarily as a component of the antioxidant enzyme glutathione peroxidase (GP), which works with vitamin E in preventing free radical damage to cell membranes.
The development of cataracts is ultimately related to free-radical damage. The lens of the eye requires adequate levels of SOD, catalase, and GP. Studies have demonstrated that low selenium levels have been found in cataract sufferers.
Selenium is involved with the production of thyroid hormone.
Selenium’s involvement in the production of glutathione peroxidase affects all aspects of immunity. Selenium supplementation results in augmentation and/or restoration of immune function, stimulating white blood cell and thymus function.
Selenium supplementation appears to increase HDL to LDL cholesterol and inhibit platelet aggregation (blood stickiness). The overall benefits on the cardiovascular system stem from the antioxidant effects of glutathione peroxidase.
Some studies indicate that selenium can be useful in the treatment of acne, while other research indicates that it may be useful in repairing chromosome damage.
Selenium and GP levels are low in inflammatory conditions such as rheumatoid arthritis, eczema, and psoriasis. GP is especially important in reducing inflammatory prostaglandins and leukotrienes.
Selenium may also help in the prevention of undesired and dangerous blood clots.
Selenium has been shown to be essential for normal fetal growth and development. Selenium levels also appear to be very low in low birth weight babies.
Selenium also helps in treatment and prevention of dandruff.
Deficiency symptoms of selenium
Although deficiencies in this mineral are rare, a deficiency in selenium may contribute to the development of cancer and heart disease, immune problems, inflammatory conditions mostly of the skin, muscular weakness and fatigue.
Researchers have found three debilitating diseases that are directly related to serious selenium deficiency. These include Myxedematous Endemic Cretinism, Keshan Disease, and Kashin-Beck Disease.
Symptoms of high intake
Large amounts can be toxic, and selenium supplements, like any other dietary supplement, should be kept well out of the reach of children.
Toxicity symptoms may include nervousness, depression, nausea, vomiting, garlic odor to breath, perspiration, loss of hair and fingernails, discolored skin, weakness, and liver damage.
The RDA for selenium is 55-70 mcg, and recommendations include 50-200 mcg.
Selenium can be toxic in high dosages, but for short-term use recommendations range from 300-600 mcg, and for long time use dosage should be no more than 300-400 mcg per day.