Dietary selenium.
Selenium is a micronutrient, which has been characterized as essential for the human body. Its importance for health has been recognized since the early '70s. The main role of the mineral is its participation in the molecular formation of an enzyme which is referred to as selenium-glutathione-peroxidase. This selenoprotein is an antioxidant and eliminates hydrogen peroxide, a free radical molecule, produced by certain cellular functions. If hydrogen peroxide is not neutralized, it can affect the cells by damaging their membranes. In combination with other free radicals, hydrogen peroxide causes oxidation and can lead to the development of numerous chronic diseases such as cancer, arthritis and heart disease.
Selenium helps in improvement of the immune system efficacy by triggering the synthesis of antibodies in response to infections and vaccinations. Studies have shown that the nutrient can play a protective role against the effects causes by the toxic properties of certain heavy metals, such as mercury, lead and cadmium. Evidence exists that selenium may contribute to cancer, and especially, to prostate cancer prevention.
Selenium may assist in co-enzyme Q10 production, protein synthesis, regulation of thyroid gland function, proper body growth and improvement of fertility. In males, for instance, the mineral improves the production and motility of sperm.
Sources of dietary selenium.
Pork, lamb, beef, liver, seafood, chicken, eggs, dairy products, whole-wheat bread, brewer's yeast, molasses, wheat germ, sunflower seeds, grains, Brazil nuts and garlic are all reliable selenium sources.
Selenium deficiency and toxicity.
Deficiency in selenium is quite common in patients who are under prolonged intravenous nutritional supply. Consequences of selenium deficiency include elevated risk for cardiovascular disease, cancer and reduced immunity. Keshan's disease is a medical condition, affecting the heart muscle and it is related to selenium deficiency, as well.
The tolerable upper intake levels for selenium have not been established yet. Problems or signs associated with toxicity, due to high intake of selenium, can be garlicky breath, loss of teeth or nails hair, alopecia, peripheral neuropathy, fatigue, skin inflammations and persistent nausea.
Recommendations for dietary selenium.
The amount of selenium in foods is dependent on the selenium content of the soil. For instance, in a part of the USA, in eastern and central Canada, in some parts of northern Europe, in New Zealand, Russia and China, the concentrations of the mineral in the soil are extremely low. For people living in these areas, moderate selenium supplementation is recommended. Such supplements may be advisable for people with gastrointestinal conditions, such as Crohn's disease that can decrease absorption of the mineral. The recommended dietary allowance (RDA) for the selenium is 55mcg for women and 70mcg for men.
Selenium food supplements are useful sources. In order deficiency to be prevented, the minimum daily intake of selenium must be 55mcg. Studies have shown that 300-400mcg of selenium per day can contribute to prevention of cardiovascular disease and certain cancers, like prostate cancer. If we consider that an average diet can provide 100-160mcg of the mineral on a daily basis, a supplementation of 200mcg/day must be adequate and safe. Click the  button, if you want to find such food supplements online.
Selenium may be more effective if it is accompanied by 400 IU of vitamin E per day. Our recommendation is the latest to be taken once a week (see recommendations for vitamin E). In other words, it can be used in the place of the plain vitamin E weekly supplementation, whereas the plain selenium preparation can be taken on a daily basis. Try this button to find such a complex supplement.
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