Minerals: Essential for Health – Selenium
Selenium is another essential mineral that follows on the heel of Chromium to help us remain fit and healthy. The many benefits of selenium include its ability to boost the body’s immune system and protect it against disease such as heart disease. It is a potent antioxidant and prevents hardening of the arteries. It increases sperm count, helps in the development of healthy fetus, supports pancreatic health and keeps skin looking young.
Selenium is a constituent of more than two dozen selenoproteins that play critical roles in reproduction, thyroid hormone metabolism, DNA synthesis, and protection from oxidative damage and infection.
While body has only a small requirement for selenium – but the small amount that is needed is essential for warding off some of the diseases and for optimum health.
Selenium is found in every cell of human body, but especially in kidneys, lever, spleen, pancreas and testes. In males, almost half of the selenium is concentrated in the testicles and the seminal ducts around the prostate gland. That is why it is considered essential to maintaining good health of the human anatomy specific to males.
As an antioxidant, selenium works with glutathione peroxidase to prevent damage by free radicals. Five selenium-containing glutathione peroxidases (GPx) have been identified:
Although each GPx is a distinct selenoprotein, they are all antioxidant enzymes that reduce potentially damaging reactive oxygen species (ROS), such as hydrogen peroxide and lipid hydroperoxides, to harmless products like water and alcohols by coupling their reduction with the oxidation of glutathione .
Sperm mitochondrial capsule selenoprotein, an antioxidant enzyme that protects developing sperm from oxidative damage and later forms a structural protein required by mature sperm, was once thought to be a distinct selenoprotein but now appears to be phospholipid hydroperoxide GPx.
Selenium acts as a powerful antioxidant – especial when combined with vitamin E.
Selenium (as Selenoproteins) helps prevent the oxidative modification of lipids, reducing inflammation and preventing platelets from aggregating – Thus, reducing the risk of cardiovascular disease.
Protection Against Cancer:
It supports cancer prevention due to its antioxidant properties and detoxification process. As an efficient antioxidant, it acts as an immune booster. There is a great deal of evidence indicating that selenium supplementation at high levels reduces the incidence of cancer in animals. More than two-thirds of over 100 published studies in 20 different animal models of spontaneous, viral, and chemically induced cancers found that selenium supplementation significantly reduces tumor incidence.
In one of the most well-known studies conducted in 1996 – [Effects of Selenium Supplementation for Cancer Prevention], late Larry Clark, Ph.D., of the University of Arizona, found a strong correlation between Selenium and an overall lower incidence of cancer risk of death.
In the study of 1,300 older people, the occurrence of cancer among those who took 200 micrograms of selenium daily for about seven years was reduced by 42 percent compared to those given a placebo. Cancer deaths for those taking the selenium were cut almost in half.
In addition, the men who took selenium had 63 percent fewer prostate cancers, 58 percent fewer colorectal cancers, 46 percent fewer lung cancers and overall 37 percent fewer cancers.
The study found that Selenium even to reduced the risk of lung cancer to a greater degree than stopping smoking.
The scientific explanations given for selenium’s anti-cancer effects include:
- Increased antioxidant protection and immune system support
- Regulation of cell proliferation and apoptosis (programmed cell death)
- Triggering DNA repair in damaged cells
- Suppression of growth of blood vessels supplying nutrients to the cancer
- Inhibition of tumor cell invasion
Rejuvenates the Body – Slows Down Aging:
Selenium and vitamin E are synergistic and enhance the effectiveness of each other. Selenium slows down aging and hardening of tissues through oxidation. It is useful in keeping youthful elasticity in tissues. It prevents arterial deposits and ensures smooth flow of blood. It is needed for healthy cardio-vascular system.
Effects on Brain Health:
Selenium is essential for proper functioning of neurotransmission. Depletion of selenium in brain causes mood swings and depression.
Effects on Sex and Menopause:
Selenium is also involved with the production of thyroid hormone. Its inadequate level would lead to decreased sexual desires. It also alleviates hot flushes and menopausal distress.
Selenium detoxifies toxic metals dangerous to our body like arsenic and mercury – It binds with these toxic metals and, once bound, the toxic substances lose their potency and become harmless.
Deficiency Symptoms of Selenium:
Per the WHO, more than 1 billion of world’s population suffers from selenium deficiency. Selenium deficiency leaves the body susceptible to cancer and severe infectious diseases.
Selenium deficiency results in decreased activity of the glutathione peroxidases as well as some other thioredoxin reductase and thyroid deiodinases. Even when severe, isolated selenium deficiency does not usually result in obvious clinical illness. However, selenium-deficient individuals appear to be more susceptible to additional physiological stresses. Deficiency of this mineral causes premature loss of stamina.
Selenium deficiency has been associated with impaired function of the immune system. Individuals who have a deficiency in selenium are often reported as becoming much more susceptible to infections, bacteria and other illnesses.
Selenium deficiency appears to enhance the virulence or progression of some viral infections. The increased oxidative stress resulting from selenium deficiency may induce mutations or changes in the expression of some viral genes.
Rich Food Sources of Selenium:
Selenium is a trace element that is naturally present in many foods. Brazil nuts contain the highest amounts of selenium than any other known food type – Mushrooms are another natural source of selenium. It is also possible to obtain selenium through other nuts, grains and seafood. Livestock who are allowed to graze on grass and grains grown in soil containing selenium, will typically contain selenium within their meat.
Supplementation & Dosage:
Recommended Dietary Allowance (RDA) for adults is 55mcg/day. But, selenium is one mineral that can be easily supplemented just by the dietary sources. Regular consumption of Brazil Nuts and incorporating grass fed meat in diet is enough to provide the needed amount of selenium.
Toxicity and Caution:
Selenium is needed in very minute quantities. High doses of selenium (in excess of 250mcg/day) can be toxic. Side effects related to taking too much selenium include a sense of fatigue, stomach problems and halitosis. This deficiency is known as Selenosis.
☞ To be on the safe side of Selenium, enjoy the Brazil nuts.
— Enjoy a Wholesome Life Naturally —
☘ ☘ ☘ ☘ ☘
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- Thomson CD, Chisholm A, McLachlan SK, Campbell JM. Brazil nuts: an effective way to improve selenium status. Am J Clin Nutr. 2008 Feb;87(2):379-84.
- Bailey RL, Gahche JJ, Lentino CV, Dwyer JT, Engel JS, Thomas PR, et al. Dietary Supplement Use in the United States, 2003–2006
- Effects of Chemical Form of Selenium on Plasma Biomarkers in a High-Dose Human Supplementation Trial
- World Health Organization, Food and Agriculture Organization of the United Nations. Vitamin and mineral requirements in human nutrition
- Lippman SM, Klein EA, Goodman PJ, Lucia MS, Thompson IM, Ford LG, et al. The effect of selenium and vitamin E on risk of prostate cancer and other cancers: the Selenium and Vitamin E Cancer Prevention Trial. JAMA 2009;301:39-51.
- Kesse-Guyot E, Fezeu L, Jeandel C, Ferry M, Andreeva V, Amieva H, et al. French adults’ cognitive performance after daily supplementation with antioxidant vitamins and minerals at nutritional doses
- U.S. Department of Agriculture, U.S. Department of Health and Human Services Dietary Guidelines for Americans, 2010
- Sunde RA. Selenium. In: Coates PM, Betz JM, Blackman MR, et al., eds. Encyclopedia of Dietary Supplements. 2nd ed. London and New York: Informa Healthcare; 2010:711-8
- U.S. Department of Agriculture, Agricultural Research Service. USDA National Nutrient Database for Standard Reference, Release 25