The trace element selenium used to be treated as a very toxic substance, but modern science now regards it as essential - but in small quantities. An overdose or deficiency of selenium is equally bad, and good steady amounts should be available - but in small quantities.
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One of the main activities of this trace mineral is its anti-aging properties and its ability to help rid the body of free radicals, as well as toxic minerals such as mercury, lead and cadmium.
It is helpful in fighting infections since it stimulates increased antibody response to infections, promotes more energy in the body, and while it helps with alleviating menopausal symptoms in women, it assists the male in producing healthy sperm.
In certain cases selenium has also proven effective in helping to fight cold sores and shingles, which are both caused by the herpes virus. Some researchers have shown that in selenium-deficient animals a harmless virus can mutate into a virulent form capable of causing damage and death - this has also been followed up with other studies, which seem to indicate that selenium helps to keep the spread and multiplying of viruses in check.
Selenium is also used against arthritis and multiple sclerosis and if provided in adequate amounts it is thought to help prevent cancer as well. Tissue elasticity and pancreatic function is also dependent on this trace mineral.
In a study it was shown that selenium could be useful in treating certain cancers, and is also helpful in making the blood less "sticky", which is helpful in preventing heart attacks and strokes.
The dosage is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
In the case of microelements, such as trace elements, the amounts are very small, yet they are still important and at least 70 micrograms per day is taken as the required dosage.
As mentioned earlier - selenium is toxic and too large quantities may result in hair loss, tooth decay, brittle nails, white spots, poor appetite, sour taste in the mouth, loss of feeling in the hands and feet, change in skin pigmentation and the breath may have a garlic smell.
Selenium should always be taken with vitamins E, A and beta-carotene, and it is preferable when taking a supplement to take selenium in the form of Selenium Amino Acid Chelate, selenocysteine or selenomethionine, which are both organic.
People with yeast intolerance should check the source of the selenium used in the supplement, as certain manufacturers obtain selenium from yeast. (we use Selenium Amino Acid Chelate)
Men need more selenium than women as it is lost in the seminal fluid, and people staying in areas where the soil is poor in selenium, should also pay attention to their selenium intake.
Brazil nuts are excellent sources of selenium, but are also found in whole grains, shellfish etc.
This trace element is a potent nutritional antioxidant that carries out its effects through its incorporation into selenoproteins, and given the crucial roles that selenoproteins play in regulating reactive oxygen species (ROS) and redox status in nearly all tissues, it is not surprising that dietary selenium strongly influences inflammation and immune responses and may be of importance in delaying the aging process. It must however be kept in mind that small quantities of this trace element must be taken, as large amounts can be toxic.
Selenium has exhaustively been shown to possess chemoprotective qualities (protection from cancer) as well as several types of malignancies and tumors.
There is a definite correlation between dietary intake of selenium and decreased and reduced prostate cancer risk and also lowered LDL cholesterol levels with no adverse effects. In one study it was found that men with prostate cancer had far lower selenium levels than other men in the control group in which prostate cancer was not evident. Not only does it help in the prevention of this cancer, but also helps to arrest the cancerous growth when administered when the cancer already manifested.
Apart from prostate cancer, it was shown that selenium is also of value fighting various types of cancer, including leukemia, bladder cancer, gastric bowel cancer, lung cancer, metastatic head and neck cancers, growth inhibition of human esophageal cancer and advanced cancers and possess potent HDAC inhibitory activities. It helps to reduce inflammation and it is active at DNA level to help protect the cells from susceptibility to cancer, and to help fight the cancer or tumor when already formed.
Selenium also has a direct influence on reducing reactive oxygen specie (ROS) (free radicals) and a study has shown that selenium has a direct bearing on reducing various cancerous growths and the studies were concluded and verified by analyzing the DNA.
It has also shown to inhibit bone cancer growth while simultaneously promoting the growth of normal bone tissue, while in another study it showed that the presence of lead contributed to breast cancer, and that there was a direct correlation between the lead and the amount of tumors, as well as a direct correlation between the tumor and an absence of selenium in the people that were tested.
Melanoma is the most fatal form of skin cancer due to its rapid metastasis and several studies reported that selenium can induce apoptosis (programmed cell death) of the melanoma cells, although the way in which it happens is still a bit unclear.
Large bowel cancer is one of the most common human malignancies in the Western world and in the USA, CRC (colorectal cancer) is the third most common type of cancer and the second most common cause of death due to cancer. In an animal study it was shown that selenium significantly inhibits iNOS, PI3 kinase signaling and pAkt signal in colon cancer cells to dramatically increase apoptosis and decrease proliferation of the cancer cells as well as inhibited colorectal cancer through epigenetic silencing.
Apart from the preventative action, selenium has also been shown to alleviate the toxicity of anticancer chemotherapy and preventing heart failure. The positive effect of dietary supplementation was also measured in a study by the Chinese Cancer Institute and it showed that the positive effects of supplementation were still evident years after the test subjects stopped the dietary supplementation.
Apart from that, another study showed that selenium is required for normal hair and skin health, and that a shortage not only resulted in abnormal hair and skin health in mice, but also premature death.
Skeletal muscle disorders manifested by muscle pain, fatigue, proximal weakness, and serum creatine kinase (CK) elevation have been reported in patients with selenium deficiency.
Selenium is needed for the proper functioning of neutrophils, macrophages, NK cells, T lymphocytes and other immune mechanisms and a deficiency in selenium in the diet can causes immune dysfunction and inflammatory disorders and adding it to the diet helps to boost the immune system, and in another study, a cocktail containing selenium as well was used to treat lung cancer patients.
It also plays an important role in the repair of oxidative DNA damage in cells as well as preventing muscle and cardiovascular disorders, immune dysfunction, cancer, neurological disorders and endocrine dysfunction and is also helpful in preventing obesity-related cancers.
All HIV patients have depleted antioxidants and a massive increase of free radicals (superoxide anion, hydrogen peroxide, hydroxil radical) and this free radical excess could impair cell membranes and generate apoptosis (cell death), the main cause of lymphocytes CD4+ depletion.
The trace element selenium may be a key nutrient associated with HIV infection and HIV patients normally have a very low selenium count. It has an inhibitory effect on HIV in vitro through antioxidant effects of glutathione peroxidase and other selenoproteins.
Low plasma selenium concentrations are related to increased risk of mortality and mycobacterial disease among people with HIV infection and are related to low hemoglobin concentrations among both HIV-infected and HIV-uninfected populations, and various studies around the world have shown an associated with lower selenium and higher HIV infection rates. It also showed a positive effect on TB patients receiving chemotherapy.
In another study done in Tanzania, HIV pregnant women were treated with dietary selenium, and although it did not stop the progression of their HIV infection, it did however improve child survival, as well as a higher survival rate of the women, while another study shown that daily selenium supplementation can suppress the progression of HIV-1 viral burden and provide indirect improvement of CD4 count.
In an American study it was found that there is an association between lower selenium levels with lower CD4 count, and higher plasma viral load and that selenium supplementation for HIV infected patients will have a beneficial effect.
Daily supplementation with selenium may also be very beneficial for patients that contacted viral hepatitis, and may be beneficial to help contracting a host of viral infections.
The thyroid gland is one of the human tissues with the highest selenium content per mass unit similar to other endocrine organs and the brain.
Selenium act as a catalyst for the production of active thyroid hormone and supplementation could also alleviate the toxic effect of excessive iodine on the thyroid gland.
It is an essential micronutrient for normal development, growth, and metabolism plus the fact that selenium is found as selenocysteine in the catalytic center of enzymes protecting the thyroid from free radicals damage.
Selenium is in addition a selenoproteins contained in the sperm mitochondrial capsule, which is vital to the integrity of sperm flagella, which influence the sperm motility (movement) of the sperm and also plays a vital role in male virility.
The selenium content of male gonads increases during pubertal maturation and is localized in the mitochondrial capsule protein (MCP) of the mid-piece of the sperm.
Men suffering with immature spermatozoa have a problem due to the fact that they are vulnerable to oxidative stress after their release from the testes due to an innate deficiency in antioxidant enzymes.
Although the reproductive tract compensates for it with antioxidant enzymes, it may influence the incidence of miscarriage.
One study concluded that supplementing with selenium does not affect testis selenium, but they used high-selenium containing yeast for the test, and not selenium amino chelate.
On the whole, most studies attest to the role of selenium in male human reproduction and the semen selenium level appears to be a useful indicator of selenium status versus reproductive function.
During pregnancy the demand of thyroid hormone increases 30 - 50% and supplementation with selenium during this time may be wise to consider, as it does support the formation of the thyroid hormone.
Selenium deficiency has been implicated as a risk factor for recurrent pregnancy loss (RPL) and in a study of diabetic pregnant mothers miscarriage was probably due to ineffective antioxidant defense, leading to a spontaneous abortion, and due to low levels of selenium and high level of pre-prandial glycaemia.
Topical application of selenium may help with skin aging, but since we are more interested in the oral intake of selenium, we contain this page's scope to the systemic intake of selenium.
There is evidence that selenium (in the form of selenoproteins) is vital in the maintenance of optimal brain functions, and a shortage could be implicated in a few age-associated neurodisorders - including Parkinson's disease, Alzheimer's disease and even epilepsy. Degeneration of the eye (macular degeneration) could also benefit from selenium supplementation.
People receiving parenteral nutrition (intravenous feeding) should also receive selenium, and burn victims should definitely be included, and although not very well researched, may be of use for patients with sepsis.
Older people should ensure that they do get enough selenium through their diet or supplementation, since it does have a pivotal role to play in reducing oxidative stress (damage caused by free radicals).
Selenium (together with zinc and niacin) may remodel the changes happening during normal aging, possibly helping to escape some age related diseases, with the consequence of healthy ageing, because they are involved in improving immune functions, metabolic homeostasis and antioxidant defense.
Extra supplementation can be helpful in the prevention and management of hypertension, cardiovascular disease, cancer and diabetes mellitus.
Long term low dose replacement of zinc, together with selenium reduce the frequency and severity of respiratory infections so often found in the elderly, and selenium in general should be considered when looking after people that have repeated infections in general.
Several studies have shown that a low selenium intake was associated with poorer mood, and cognitive impairment.
The role of selenium in the prevention of a number of degenerative age-related conditions including cancer, inflammatory diseases, thyroid function, cardiovascular diseases, neurological diseases, ageing, infertility, and infections, has been established by laboratory experiments, clinical trials, and epidemiological data.
Most of the effects in these conditions are related to the function of selenium in the antioxidant enzyme systems and supplementing selenium in deficiency conditions appears to have immune-stimulating effects, particularly in patients undergoing chemotherapy. However, increasing the levels of selenoprotein antioxidant enzymes (glutathione peroxidase, thioredoxin reductase, etc.) appears to be only one of many ways in which selenium-based metabolites contribute to normal cellular growth and function.
Animal data, epidemiological data, and intervention trials have shown a clear role for selenium compounds in both prevention of specific cancers and in the anti-tumorigenic effects in post-initiation phases of cancer.