Selenium Deficiency

The essential trace mineral selenium functions primarily as a component of the antioxidant enzyme glutathione peroxidase, which works with Vitamin E in preventing free radical damage to cell membranes. New Zealand soils are selenium deficient. Low levels of selenium are linked to a higher risk for cancer, cardiovascular disease, inflammatory diseases and other conditions associated with free-radical damage, including premature aging and cataract formation. Selenium is also antagonistic to heavy metals such as lead, mercury, aluminium and cadmium and can reduce their toxic effects.

Selenium, in its vital role in glutathione peroxidase, positively affects all components of the immune system, including the development of white blood cells, an integral part of the body’s natural defence force. While Vitamin E works synergistically with selenium in raising glutathione peroxidase activity, selenium absorption is adversely affected by heavy metals. Various drugs, particularly chemotherapy drugs, are likely to increase selenium requirements.

Selenium absorption may be reduced as a consequence of aging and in addition, older people often consume less selenium-containing fresh and whole foods (food sources for selenium include tuna, oysters, mushrooms, herrings, cottage cheese, cabbage, beef liver, courgettes, and cod). Selenium deficiency is more common where soils are low in selenium and also in infants who are fed cow’s milk instead of breast milk.

While no clearly defined deficiency syndrome has been accepted, given selenium’s many important functions and uses, its deficiency may generate increased risk of certain cancers, cardiovascular disease, hypertension, strokes, myocardial infarction (heart attack) and kidney disease. Other problems possibly associated with deficiency include: eczema, psoriasis, rheumatoid arthritis, pancreatitis, cataracts, cervical dysplasia and alcoholism.