Selenium

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Other names for selenium

Sodium Selenite
Selenomethionine
Selenium Yeast
L-selenocysteine

Synopsis of selenium

Selenium is an essential trace mineral that plays a critical role in human health through its incorporation into selenoproteins—enzymes that regulate antioxidant defense, thyroid hormone metabolism, DNA synthesis, and immune function. It exists in both organic (selenomethionine, selenocysteine) and inorganic (selenate, selenite) forms, and its biological effects depend on its form and bioavailability. Dietary selenium is typically sourced from Brazil nuts, seafood, meats, whole grains, and vegetables grown in selenium-rich soils.

One of selenium's most vital functions is as a cofactor for glutathione peroxidase, a major antioxidant enzyme that protects cells from oxidative stress. It also supports the enzyme iodothyronine deiodinase, which is necessary for converting inactive thyroid hormone (T4) into its active form (T3), thereby playing a fundamental role in thyroid health. Selenium is also important in immune regulation, reproductive health, and reducing inflammation. Deficiency in selenium has been linked to thyroid dysfunction, weakened immunity, infertility, and increased susceptibility to viral infections.

In supplementation, selenium is commonly used in multivitamin formulas, thyroid support blends, and antioxidant complexes. Research suggests it may have protective roles in cancer prevention, cardiovascular health, and cognitive function, although optimal dosing is crucial—excess selenium can be toxic.

Historical Use:
Selenium was discovered in 1817 by the Swedish chemist Jöns Jakob Berzelius, but it wasn't until the mid-20th century that its biological significance was fully recognized. Before that, its presence in certain plants and animals was known more for toxicological than nutritional reasons. In regions with high natural selenium levels in the soil, such as parts of the U.S. Great Plains and China, livestock occasionally developed selenosis from overconsumption of selenium-rich vegetation, leading to early awareness of its potent effects.

The turn toward recognizing selenium as a nutritional necessity came with studies in the 1950s and 1960s, showing that animals fed selenium-deficient diets developed liver necrosis and other dysfunctions, which could be reversed with supplementation. By the 1970s, selenium was accepted as essential for human health, especially due to its role in glutathione peroxidase.

In traditional healing systems, selenium-rich foods like Brazil nuts and certain seafoods were used for strength, fertility, and resilience against disease—long before the mineral itself was isolated. In Chinese folk medicine, marine sources such as seaweed and shellfish—both naturally high in selenium—were used to strengthen the kidneys, thyroid, and immune function. These traditional practices mirrored selenium’s biological functions, even if their mechanisms were not yet scientifically understood.

Selenium is used for these health conditions

Acquired Immune Deficiency Syndrome (Scientific)
Aging (prevention) (Scientific)
Alzheimer's Disease (Scientific)
Arrhythmia (Scientific)
Athlete's Foot (Scientific)
Autoimmune Disorders (Scientific)
Bell's Palsy (Scientific)
Blood Poisoning (Scientific)
Burns and Scalds (Scientific)
Cancer (natural therapy for) (Scientific)
Cancer (prevention) (Scientific)
Cancer Treatment (reducing side effects) (Scientific)
Cardiovascular Disease (Scientific)
Carpal Tunnel Syndrome (Scientific)
Cervical Dysplasia (Scientific)
Chemical Poisoning (Scientific)
Chemotherapy (reducing side effects) (Scientific)
Cirrhosis of the Liver (Scientific)
Dementia (Scientific)
Depression (Scientific)
Eye Problems (Scientific)
Free Radical Damage (Scientific)
Goiter (Scientific)
Grave's Disease (Scientific)
Hair (loss or thinning) (Scientific)
Hepatitis (Scientific)
Infection (Scientific)
Infection (viral) (Scientific)
Inflammation (Scientific)
Influenza (Scientific)
Liver Detoxification (Scientific)
Memory and Brain Function (Scientific)

selenium is used to support these body systems

Blood (Scientific)
Brain (Scientific)
Circulatory System (Scientific)
Female Reproductive System (Scientific)
Glandular System (Scientific)
Hair (Scientific)
Heart (Scientific)
Immune System (Scientific)
Liver (Scientific)
Male Reproductive System (Scientific)
Mitochondria (Scientific)
Nails (Scientific)
Prostate (Scientific)
Reproductive System (Scientific)
Reproductive System (Scientific)
Skin (Scientific)
Testes (Scientific)
Testosterone (Scientific)
Thyroid Gland (Scientific)