WHAT IS SELENIUM?
Selenium is a micromineral (or trace element) that protects your body from damaging free radicals (a harmful by-product of oxygen related reactions in the body) and reduces inflammation in the body. In this article I will be providing you with an in-depth look at this important nutrient.
WHEN WAS SELENIUM DISCOVERED?
Selenium was discovered by the two Swedish chemists Jons Jakob Berzelius and J. G. Gahn in 1818. They were studying the chemicals within sulphuric acid and found a material that they thought was the rare element tellurium. Berzellius studied this material more closely and discovered that whilst it was similar to tellerium it actually had different properties and was a new element which he named selenium.
HOW DOES YOUR BODY USE SELENIUM?
An average adult stores around 15 milligrams (mg) of selenium in their body. As I mentioned above the main role of selenium is as an antioxidant that protects you from free radicals. However, it has a number of other important roles in the body which include supporting your immune system (through the production of antibodies) and protecting your body from disease. The list below outlines the main roles of selenium in the body:
– Acting as an antioxidant by protecting your body’s cells from free radicals.
– Assisting in the production of antibodies (organisms that fight disease in the body).
– Assisting in the production of the antioxidant coenzyme Q10.
– Assisting with and regulating the production of triiodothyronine (a thyroid hormone also known as T3 that affects almost every process in the body including the generation of body heat, growth and heart rate).
– Assisting in the transport of ions across cell membranes.
– Possibly slowing the progression of the human immunodeficiency virus (HIV) (more research is needed in this area).
– Preventing certain types of cancer including colon cancer, lung cancer and prostate cancer.
– Preventing heart disease.
– Reducing joint inflammation.
– Relieving the symptoms of arthritis.
– Supporting male fertility.
– Working with vitamin C and vitamin E to boost the body’s antioxidant function.
HOW MUCH SELENIUM DO YOU NEED?
The body’s requirement for selenium increases with age. In 2000 the Institute of Medicine at the National Academy of Sciences set the following recommended daily allowances (RDAs) for selenium:
– Children aged 0-6 months:- 0.015mg.
– Children aged 7 months-3 years:- 0.02mg.
– Children aged 4-8 years:- 0.03mg.
– Children aged 9-13 years:- 0.04mg.
– Children and adults aged 14 years and older:- 0.055mg.
– Pregnant women:- 0.06mg.
– Lactating women:- 0.07mg.
WHICH FOODS CONTAIN SELENIUM?
Nuts and fish are the amongst the best food sources of selenium. The list below contains a selection of selenium rich foods:
– Brazil Nuts:- 1.92mg per 100g.
– Mixed Nuts:- 0.42mg per 100g.
– Salmon:- 0.038mg per 100g.
– Shrimp:- 0.048mg per 100g.
– Tuna Canned in Oil:- 0.076mg per 100g.
WHAT ARE THE SYMPTOMS OF GETTING TOO MUCH SELENIUM?
Overdosing on selenium from food alone is rare but it is possible when taking supplements. Because of this the National Academy of Sciences established a daily tolerable upper limit (TUL) of 0.4mg in 2001. Extremely high levels of selenium in the body are referred to as selenosis and can lead to the following negative symptoms:
– Bad breath.
– Fatigue.
– Gastrointestinal problems.
– Hair, nail and tooth loss.
– Increased dental cavities.
– Irritability.
– Loss of feeling in the fingers and toes.
– Mild nerve damage.
– White blotchy nails.
WHAT ARE THE SYMPTOMS OF NOT GETTING ENOUGH SELENIUM?
Failing to get enough selenium in your diet is very rare. However, it has been observed in countries such as China where the concentration of selenium in the soil is very low. Serious gastrointestinal problems can also lead to selenium deficiencies as the body will struggle to absorb adequate levels of this nutrient. People who are fed intravenously for long periods of time are also at risk of selenium deficiency. If a deficiency does develop it can lead to a number of undesirable symptoms which include:
– Increased cancer risk.
– Kashin-Beck disease (a bone and joint disorder caused by selenium deficiency).
– Keshan disease (a heart disorder caused by selenium deficiency).
– Myxedematous endemic cretinism (a disease that causes mental retardation).
– Osteoarthritis (the chronic breakdown of cartilage in the joints).
– Skin inflammation.
– Weak immune system.
SELENIUM SUMMARY
Selenium acts mainly in a protective capacity and helps keep your body free from infections and disease. Failing to get enough can lead to a number of unpleasant conditions. So to keep your body fighting fit make sure you get the RDA of this important nutrient.
Now I want to hear your thoughts. Do you consume enough selenium rich foods? Were you aware of all the protective roles it has in the body? Leave a comment and let me know.
Sources:
Selenium in Diet and Nutrition (New York Times)
Selenium (Chemistry Explained)
Selenium (Dietary Fibre Food)
Selenium (Internet Health Library)
Selenium (Life Clinic)
Selenium (Medpedia)