Se is an unusual trace element in having its own codon in mRNA that specifies its insertion into selenoproteins as selenocysteine (SeCys), by means of a mechanism requiring a large SeCys insertion complex. This exacting insertion machinery for selenoprotein production has implications for the Se requirements for cancer prevention. If Se may protect against cancer, an adequate intake of Se is desirable.

Newly-published prospective studies on oesophageal, gastric-cardia and lung cancer have reinforced previous evidence, which is particularly strong for prostate cancer. Interventions with Se have shown benefit in reducing the risk of cancer incidence and mortality in all cancers combined, and specifically in liver, prostate, colorectal and lung cancers. The effect seems to be strongest in those individuals with the lowest Se status.

Cognitive performance declines naturally with age, but the results of the new study published in the "American Journal of Epidemiology" suggest that this increased long-term selenium intake may slow this decline. A person's selenium intake throughout life may influence how well they retain cognitive function as they age.

Sujuan Gao the study's lead author reports that the "Selenium exposure, unlike other factors studied for Alzheimer’s disease, is a factor that is easily modifiable by changing dietary habits or through supplements."

"Long-term exposure to selenium may be needed to impact brain function later in life," the study says. Selenium supplementation is also reported to improve confused and depressed mental states, mental fatigue and anxiety in adults.

Most importantly, preventive measures for cognitive decline can prolong the state of healthy aging and maintain the quality of life for many elderly individuals.

Metabolic Syndrome is condition closely related to diabetes. The syndrome has been linked to increased risks of both type 2 diabetes and CVD.

Researchers from the University of Navarra in Pamplona, Spain, conducted a study of 100 healthy young adults (average age of 20.7) and found that Selenium status appears to be linked with serum complement factor 3, which has been reported to be a marker for increased risk of the metabolic syndrome.

An increased intake of selenium may decrease risk factors for Metabolic Syndrome and inflammation.

The role of nutrition in infectious diseases has long been associated with changes in the immune response of the nutritionally deficient host.

The discovery that the juvenile cardiomyopathy known as Keshan disease likely has a dual etiology that involves both a nutritional deficiency of the essential trace mineral selenium (Se) as well as an infection with an enterovirus provided the impetus for additional studies of relationships between nutrition and viral infection.

Insufficient intake of Se enhances predisposition to diseases associated with oxidative stress to cells and tissues while supplementation has been shown to confer health benefits such as enhanced immune competence and resistance to viral infections.