Laucke Bio-Fort Selenium - About Selenium

Selenium is an essential trace mineral that functions largely in the form of proteins, called selenoproteins, which act as enzymes and help prevent damage to cells in the body by oxidants in the environment or those produced by normal metabolism.

Selenium is named after Selene the goddess of the moon. It is one of the rarest of the elements on earth, and is a key component in all living systems. Without it, humans or animals could not develop properly or survive for long. Therefore, it is classed as an essential micronutrient for humans and animals and plants alike. It is located in Group 16 on the Periodic Table of the Elements and is classified “non-metallic”. Non-metals are not able to conduct electricity or heat very well. As opposed to metals, non-metallic elements are very brittle, and cannot be rolled into wires or pounded into sheets. The non-metals exist in two of the three states of matter at room temperature: gases (such as oxygen) and solids (such as carbon). The non-metals have no metallic luster and do not reflect light. They have oxidation numbers of ±4, -3, and -2.

The important biological actions of Selenium (such as antioxidant, anti-cancer and anti-heart disease effects) are not properties of the element per se, but rather of its various chemical forms. The most common inorganic Selenium forms are selenite and selenate, while two of the major organic forms are selenomethionine (the major form in food) and selenocysteine (the 21st amino acid, and component of selenoproteins, many of which have vital enzyme functions in the body). Most Selenium ingested by humans comes from the soil, taken through plants growing in the soil. Fish is also an important dietary source of Selenium.

We are fortunate that plants such as cereals are able to extract Selenium from the soil, convert it into the most suitable forms for humans to eat (selenomethionine and other organic Selenium forms), and store it in their edible parts (e.g. grain). [link to Bio-Fort page]

It is important that people of all ages incorporate adequate daily levels of Selenium into their diet. Inadequate intake of selenium will result in adverse health consequences. There is evidence that infants who are low in the element are at higher risk of infections and other conditions associated with high oxidative stress, such as cot death. This is more likely if the mother has smoked and/or consumed a poor diet during pregnancy. In fact, pregnant or lactating women should eat more Selenium. Other groups at risk of insufficient Selenium intake and its consequences include smokers (especially men), the frail elderly, and anyone else who is subject to oxidative stress. [link to How Much Selenium do I need?]

Why is SELENIUM important for humans? The following diagram & list summarises major research findings on the effects of Selenium on human health. If you would like to know more about any of these, please click on the 'tell me more' button for each category below, or follow the navigational links at the top of this page.

Reducing risk and progression of cancer: [top] [back to diagram]
World Selenium expert, Professor Gerald Combs from the USA has stated: “There is no more extensive body of evidence for the cancer preventive potential of a normal dietary component than there is for selenium.” (Pharmacology & Therapeutics 1998; 79: 179-192). Forty years of research has shown that low Selenium soil levels and intakes tend to be associated with higher cancer incidence and mortality. [tell me more]

Enhancing immunity: [top] [back to diagram]
Selenium is essential to maintain an effective immune system, has diverse roles, and is normally abundant in immune tissues such as liver, spleen, and lymph nodes. Selenium deficiency reduces immunity, and supplementation of even supposedly selenium-replete individuals improves immunity by stimulating neutrophils, natural-killer-cells, T & B lymphocytes and macrophages. In addition, Selenium assists the immune system through its anti-viral effects. [link to more]

Anti-asthma, rheumatoid arthritis, muscular dystrophy, cystic fibrosis, pancreatitis effects: [top] [back to diagram]
Antioxidant effects:
Free radicals are atoms or groups of atoms with an odd (unpaired) number of electrons and can be formed when oxygen interacts with certain molecules. Once formed these highly reactive radicals can start a chain reaction, like dominoes. Their chief danger comes from the damage they can do when they react with important cellular components such as DNA, or the cell membrane. Cells may function poorly or die if this occurs. To prevent free radical damage the body has a defence system of antioxidants.
Antioxidants are molecules which can safely interact with free radicals and terminate the chain reaction before vital molecules are damaged.
Selenium’s vital roles in the body are mostly conducted by selenoenzymes, of which at least 35 have been discovered. They include selenoprotein P (selenium transporter in the blood and brain), the thioredoxin reductases (maintenance of cellular oxidation-reduction balance, and synthesis of DNA), and the glutathione peroxidase family. New selenoenzymes are being discovered all the time! The glutathione peroxidases reduce harmful hydroperoxides and scavenge free radicals that cause continual damage to cells. [link to more]

Diseases & Conditions:
Selenium can alleviate other conditions (in addition to heart disease, diabetes and some cancers) associated with high levels of inflammation and oxidative stress. Individuals with asthma, for example, tend to have increased oxidative activity, lowered selenium status, and decreased activity of glutathione peroxidase. Published studies of selenium deficiency and the preventive and clinical effects of selenium supplementation on asthma support the concept of selenium administration. [link to more]

Reducing heart disease and diabetes risk: [top] [back to diagram]
Selenium’s antioxidant action reduces damage to lipids, lipoproteins and DNA, and alleviates inflammation/platelet aggregation, and hence reduces risk of heart disease. Moreover, it helps regulate blood pressure and can reduce blood homocysteine level, two important heart disease risk factors. [tell me more]

Helping to control dangerous viruses: [top] [back to diagram]
Selenium has a direct effect against RNA viruses like influenza, measles, polio, hepatitis B & C, and HIV. When Selenium is deficient, or even merely marginal, the viruses become more active and virulent. Studies have shown Selenium deficiency to be associated with faster progression to AIDS among HIV-positive individuals, and increased risk of progression to fibrosis, cirrhosis and liver cancer in people with hepatitis B or C. [link to more]

Improving brain function: [top] [back to diagram]
Several selenoenzymes have important roles in the brain (e.g. selenoproteins M, P & W; glutathione peroxidase; thioredoxin reductase), where they are potent protective agents for neurons. Low Selenium levels have been associated with cognitive impairment, depression, anxiety and hostility. In one study, the brain selenium levels in Alzheimer’s patients was only 60% of that in controls. Selenium supplementation can reduce cognitive decline in the elderly, probably by preserving dopamine and neurons in the substantia nigra, and by reducing lipid peroxidation. [link to more]

Improving fertility: [top] [back to diagram]
In men, Selenium is necessary for testosterone biosynthesis and also for sperm development and function. In women, Selenium, due to its antioxidant effects, can reduce the risk of miscarriage. [tell me more]

Important thyroid function role: [top] [back to diagram]
The thyroid gland has the highest Selenium and Iodine concentrations of all organs in the human body. Both Selenium and Iodine are required for thyroid hormone synthesis, activation and metabolism. [tell me more]

Selenium is a co-factor for the enzyme glutathione peroxidase, which aids in the regeneration of glutathione. It is also a major antioxidant nutrient that protects cell membranes and prevents free radical generation, thereby decreasing the risk of cancer and disease of the heart and blood vessels. Glutathione and glutathione related enzyme precursors riboflavin and selenium are protective against Age-Related Macular Degeneration (ARMD) (Sternberg, Davidson, Jones, et al. Invest Ophth Vis Sci, 1993).

Several studies indicate a role for Selenium in the treatment of severe bacterial infections, such as acute septicaemia. This is particularly relevant in view of increasing resistance of bacteria to standard antibiotics. Moreover, low Selenium status is an important risk factor for developing mycobacterial disease (e.g. tuberculosis) in HIV-positive individuals.

Evidence is accumulating for important interactions of Selenium with various other minerals in the body, including zinc, copper, iron and manganese. Selenium appears to have a normalising effect on other minerals in organs and blood cells. For example, a Serbian study found that marginally low zinc, iron and copper levels, along with abnormally high manganese levels in red blood cells were all normalised after people consumed Selenium-enriched wheat, while low-Selenium wheat had no effect.

Selenium is a well-known detoxifier of toxic metallic pollutants. It has a high affinity for toxic metals such as cadmium and mercury, and for the metalloid arsenic, binding with them and rendering them harmless. In the case of cadmium and mercury, detoxification is achieved through the diversion in their binding from low- to high-molecular-weight proteins.
Numerous studies have found that Selenium and other antioxidants and phytochemicals have the effects of both enhancing the anti-cancer action of chemotherapy and radiotherapy and reducing the damage caused by these therapies to normal cells. [link to more]