Selenium

General Info

Absorption

Selenium salts and compounds are readily absorbed in the small intestine.

Dietary Origins

Whole grains are the best dietary source of selenium followed by dairy products, eggs, liver, seafood, some vegetables including cabbage, celery, cucumbers, garlic, and radishes.

Overview

Selenium is an essential trace mineral found naturally in the soil. Much of what is known about selenium is based on observation of deficiency states caused by low levels of soil-selenium in certain regions of the world, and the food sources produced from that soil. Selenium plays important roles in detoxification and antioxidant defense mechanisms in the body.

Toxicities & Precautions

General

Selenium is a trace mineral that could be toxic if extreme amounts were ingested on a regular basis. Symptoms of selenium toxicity may include loss of hair and nails, skin lesions, digestive dysfunction, nervous system abnormalities, and breath odor. No deaths have occurred in humans from selenium toxicity.

Functions in the Body

Anti-cancer Benefits

Low dietary selenium intakes have been associated with higher rates of cancer.

Antioxidant

Selenium helps to reduce and neutralize free radical damage. Selenium also potentiates the antioxidant activity of vitamin E.

Detoxification

Helps detoxify heavy metal toxins such as cadmium and mercury.

Heart Disease

Selenium's antioxidant activities may help to protect against heart attacks and strokes.

Thyroid

Recently discovered that the enzyme that converts thyroid hormone, T4, to Triiodothyronine, the active form of T3, is a selenium-dependent enzyme.

Symptoms & Causes of Deficiency

The symptoms of selenium deficiency include the following; destructive changes to the heart and pancreas, increased red blood cell fragility, sore muscles, and a weakened immune system. The primary cause of selenium deficiency is insufficient dietary intake due to either poor food choices, or eating foods grown in seleniumdepleted soils. Selenium is not an essential nutrient for plants and thus, many farmlands have become increasingly depleted of selenium because farmers see no need to add it to the soil. Food processing causes substantial loss of selenium. For example, whole wheat bread has twice the selenium as white bread, and brown rice has 15 times more selenium than white rice. Human breast milk contains six times more selenium than cow's milk. A cow's milk diet for infants can contribute to low selenium levels and depressed immune systems in infants. Protein-calorie malnutrition can also lead to selenium deficiency. Increased rates of various types of cancer are associated with low dietary intake of selenium.