Dietary sources of selenium (1)

SELENIUM is a dietary mineral that is primarily found in the soil. The level of selenium in other sources such as plants and water is dependent on its level in the soil where the plant grows or where the water is gotten from. It is a trace mineral that is essential in many metabolic reactions in the body. Also, selenium is an antioxidant, which protects various cells in the body against free radical damage.

Uses 

Selenium as a trace element is required for the proper functioning of the glutathione peroxidases (one of the enzyme antioxidant defence systems). These are enzymes that protect against oxidative stress damage of cells in the body. These enzymes also play a role in detoxifying the body. They are capable of recycling used Vitamin C to be re-used and thereby prolong the life span of Vitamin C and its antioxidant function. 

      Furthermore, selenium supports the enzyme that is responsible for transforming T4 thyroid hormone (thyroxine) to the more active T3 hormone (triiodothyronine). Together with iodine, selenium, enhances the function of the thyroid gland. It also helps the immune system to function properly. In its antioxidant function, selenium works in combination with Vitamin E. 

Sources of selenium

      Selenium is primarily found in the soil, as I mentioned earlier. The concentration of selenium in water and plants depends on the location, whether there is selenium or not. Selenium can be found in water and the following sources: Seafood and fish such as oysters, crab, tuna, shrimps, salmon, sardines and cod. Poultry sources include chicken and turkey, red meat is also a good source of selenium. 

      Vegetable sources are asparagus, barley, flaxseed, spinach, cabbage, garlic and broccoli. Whole grains and nuts also have high content of selenium. Examples are whole wheat and wheat gem, Brazil nuts and walnuts. 

Health benefits of selenium 

      Research has shown that selenium might play a positive role in some diseases. Diseases such as cardiovascular diseases, cancer and thyroid disease. Deficiency of selenium in the body, a very rare occurrence, may be associated with conditions like Human Immuno-deficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS), rheumatoid arthritis and Crohn’s disease. Selenium has also shown some promises in the treatment of asthma, arthritis, dandruff and infertility in men, hypothyroidism, macular degeneration and cataract. 

Cancer 

    In the management of cancer, the antioxidant property of selenium is brought into play. Not only that, selenium also plays a role in the repair of damaged DNA and in programmed cell death, known as apoptosis. It is also involved with boosting the immune system and the endocrine organs’ function. The type of cancer in which selenium has been found to be most effective is the prostate cancer in men. On-going research has begun to throw more light into the effectiveness of selenium in other types of cancer; colorectal, bladder, gastric, oesophageal and lung cancers. Research has so far, not shown any association between breast cancer and selenium. High levels of selenium in the body may increase the risk of skin cancer. Cardiovascular disease 

Selenium, acting as co-factor to glutathione peroxidase enzyme helps to prevent the oxidative damage of lipids in the cell membranes. The inflammation and platelet agglutination that would have accompanied this process is also averted. Plaques, which would have been formed and deposited on the blood vessels are also prevented by this action of the enzyme and selenium. Selenium also lowers the blood level of total cholesterol but increases High Density Lipo-protein (HDL) cholesterol. It can be said to prevent atherosclerosis, coronary artery disease and stroke. 

Thyroid disease and selenium deficiency 

        Selenium deficiency is a rare occurrence. It is seen more in diseases of the intestines that affect their ability to absorb nutrients, for example Crohn’s disease. Selenium is very important in the function of the thyroid gland. 

     t is involved in the production of thyroid hormone and balancing of the hormone in the tissues and organs of the body. It helps to convert the thyroid hormone, thyroxine (T4) to the more active and usable form, triiodothyronine (T3). Furthermore, selenium protects the thyroid gland tissues against the effects of stress and helps to recycle iodine so as to prolong its use. 

     Symptoms of selenium deficiency include nausea, weakness, muscular pain, change of colour of the skin, hair and nails. 

      Goitre, a swelling of the thyroid gland usually in the front of the neck is a condition caused by deficiency of iodine. However, research has shown that in goitre there is also deficiency of selenium. In the management of goitre therefore, supplements of selenium should also be administered.