Selenium

Selenium is a non-metallic chemical element and an essential mineral found in small amounts in the body and in the soil. Selenium naturally appears in water and some foods. While people only need a very small amount, selenium plays a key role in the metabolism.

Chemically, it is represented with the chemical symbol Se and its atomic number is 34. In the periodic table, it belongs to the same group as oxygen and sulfur. It was discovered in the year 1817 by famous Swedish chemist Jons Berzelius. If you ask me what is selenium good for, then let me tell you that the importance of this non metal is not just confined to chemistry but it plays a major role in various biological functions and has several practical applications as well.

Most of the selenium in the body comes from the diet. The amount of selenium in food depends on where it is grown or raised. Crab, liver, fish, poultry, and wheat are generally good selenium sources. The amount of selenium in soils varies a lot around the world, which means that the foods grown in these soils also have differing selenium levels. In the U.S., the Eastern Coastal Plain and the Pacific Northwest have the lowest selenium levels.

How It Works

Selenium is important for making many body processes work correctly. It seems to increase the action of antioxidants, especially when combined with vitamin E. Antioxidants like selenium help fight damaging particles in the body known as free radicals. Free radicals can damage cell membranes and DNA, and may contribute to aging and a number of conditions, including heart disease and cancer. Antioxidants can neutralize free radicals and may reduce or even help prevent some of the damage they cause.

Selenium plays a role in thyroid function and your immune system needs selenium to work properly. People with a number of conditions, ranging from rheumatoid arthritis to some types of cancer, often have low levels of selenium. However, in most cases scientists aren't sure whether low selenium levels are a cause or an effect of the disease.

Selenium Uses

• Selenium is a useful catalyst for various important chemical reactions. So, it is used in laboratories and chemical industries for the same purpose.

• The most important commercial use of selenium is in the glass making industry. In glass manufacturing, it helps in canceling out the greenish effect caused by the presence of iron impurities. Thus, it gives a colorless and transparent effect to the glass. Sometimes, it is also used as a component in manufacturing of glass to add a deep red color to the glass.

• Selenium is capable of converting light energy into a usable form of electricity. Hence, it is used in the manufacturing of solar cells.

• Selenium is also associated with other industries like that of ceramic manufacturing and in the making of brass. It has a major role in printing and copying technology as well.

• It is a vital component of various vitamin and mineral supplements and is used for treating various health problems. It is often administered to people suffering from Keshan disease, asthma, burns injuries and malabsorption of nutrients. It is also used to counteract the side effects of chemotherapy.

Selenium Benefits

• Selenium has excellent antioxidant properties that protect the chromosomes of our body cells from the damaging effect of free radicals. Thus, it reduces the chances of development of various types of cancer.

• It can lower the level of cholesterol in the blood and maintain healthy blood pressure. Thus, it takes care of the heart health.

• It works along with vitamin E and helps in removal of various forms of toxic substances from our body.

• It plays a major role in normal functioning of the thyroid gland. In absence of selenium, the thyroid gland will start functioning very slowly.

• High amount of selenium can be found in the liver and kidneys. It helps out these organs in carrying out various metabolic processes of the body.

• One of the important selenium benefits is that it is one of the most vital components that can give us healthy looking skin.

• Deficiency of selenium can lead to various health problem. It can cause Keshan disease, which weakens the heart so much that it cannot pump enough blood to various parts of the body. It can have an adverse impact on the thyroid function. People suffering from selenium deficiency can suffer from weak immune system, hypothyroidism, fatigue and other problems.

The major role of selenium in our body is to boost the immune system and activation of anti oxidant enzymes. These activities are vital for metabolism and body functions. It is concentrated in the kidneys, liver, muscles and the thyroid. Selenium is also known to fight against cancer cells. Natural killer cells are formed in the body with selenium intake which destroy any foreign bacteria entering our body.

Selenate and selenite are the inorganic forms of selenium. The gastrointestinal absorption of these inorganic forms in fraction, is less than 45% - 50%. Selenate is absorbed more as compared to selenite, but selenite has better retention properties. Selenium is eliminated through urine and small amounts of it is passed through feces.

The major health benefits of selenium include prevention of hardening of arteries. Selenium is known to aid pregnant women in healthy fetus development, it also helps to keep the skin looking young. The pancreas and its function is greatly benefited by the consumption of selenium. Semen production is significantly increased and can be attributed as a health benefit of selenium. Another vital nutritional benefit of selenium is increasing the ratio of HDL cholesterol to LDL cholesterol which is vital for a healthy heart. It also reduces the severity of cold sores and shingles, fights viral infections and helps relieve lupus symptoms. Cataracts and macular degeneration are known to be the leading causes of impaired vision or blindness in the elderly. Selenium may be useful in preventing the same. Thyroid hormone is vital for the functioning of every cell in the body, selenium aids in converting this hormone from a less active form (called T4) to its active form (known as T3).

Selenium's role in combating cancer has garnered a lot of attention recently. A five-year study conducted at the University of Arizona and the Cornell University showed that consumption of 200 mcg. of selenium daily resulted in 63% fewer prostate tumors, 58% fewer colorectal cancers, 46% fewer lung malignancies, and a 39% overall decrease in cancer deaths.

The health benefits of selenium supplements include making of antioxidants which fight against the free radicals that damage cells resulting in aging. Selenium benefits for hair have shown prevention of dandruff. Selenium compounds help to kill the fungus (Malassezia) present on the scalp, which sheds dry skin fragments. Some amount of selenium is also used in the anti-dandruff shampoos. Selenium benefits for skin include prevention of acne and skin cancer.

Selenium Deficiency

Human selenium deficiency is rare in the U.S. but is seen in other countries, most notably China, where soil concentration of selenium is low. There is evidence that selenium deficiency may contribute to development of a form of heart disease, hypothyroidism, and a weakened immune system. There is also evidence that selenium deficiency does not usually cause illness by itself. Rather, it can make the body more susceptible to illnesses caused by other nutritional, biochemical or infectious stresses.

Three specific diseases have been associated with selenium deficiency:

• Keshan Disease, which results in an enlarged heart and poor heart function, occurs in selenium deficient children.

• Kashin-Beck Disease, which results in osteoarthropathy.

• Myxedematous Endemic Cretinism, which results in mental retardation.

Keshan disease was first described in the early 1930s in China, and is still seen in large areas of the Chinese countryside with selenium poor soil. Dietary intake in these areas is less than 19 micrograms per day for men and less than 13 micrograms per day for women, significantly lower than the current RDA for selenium. Researchers believe that selenium deficient people infected with a specific virus are most likely to develop Keshan disease.

Selenium deficiency has also been seen in people who rely on total parenteral nutrition (TPN) as their sole source of nutrition. TPN is a method of feeding nutrients through an intravenous (IV) line to people whose digestive systems do not function. Forms of nutrients that do not require digestion are dissolved in liquid and infused through the IV line. It is important for TPN solutions to provide selenium in order to prevent a deficiency. Physicians can monitor the selenium status of individuals receiving TPN to make sure they are receiving adequate amounts.

Severe gastrointestinal disorders may decrease the absorption of selenium, resulting in selenium depletion or deficiency. Gastrointestinal problems that impair selenium absorption usually affect absorption of other nutrients as well, and require routine monitoring of nutritional status so that appropriate medical and nutritional treatment can be provided.

Symptoms of Selenium Deficiency

• Keshan disease is caused by deficiency of selenium and this condition affects the heart. This condition weakens the heart and is mainly seen in kids. Keshan disease causes loss of heart tissues and arrhythmias.

• Selenium deficiency symptoms include joint problems too. Kashin-Beck's disease, which causes deterioration of the joint tissues, is caused by selenium deficiency.

• Another medical condition that is linked to selenium deficiency is hypothyroidism. This is due to the active participation of selenium in the conversion of thyroid hormone called thyroxine.

• Other selenium deficiency symptoms include extreme fatigue, mental slowing, muscle weakness and pain, hair or skin discoloration, miscarriage, etc.

• When there are lowered selenium levels in the body, it lowers the immunity of the body and therefore it can lead to increased chances of several diseases attacking the body.

• Of these autoimmune diseases, Keshan disease (enlarged heart), Kashin-Beck (osteoarthropathy) and Myxedematous Endemic Cretinism (Hypothyroidism leading to mental retardation) are the most common.

• It makes a person more susceptible to developing cancer and HIV/AIDS.

• There are increased chances of developing thyroid problems.

• It increases fatigue in the body.

• Selenium deficiency can also lead to hair loss and weak nails.

Selenium Food Sources

Brewer's yeast and wheat germ, liver, butter, fish (mackerel, tuna, halibut, flounder, herring, smelts) and shellfish (oysters, scallops, and lobster), garlic, whole grains, sunflower seeds, and Brazil nuts are all good sources of selenium. Selenium levels in food depend on how much selenium was in the soil where the food was grown. Selenium is destroyed when foods are refined or processed. Eating a variety of whole, unprocessed foods is the best way to get selenium in your diet.

Plant foods are the major dietary sources of selenium in most countries throughout the world. The content of selenium in food depends on the selenium content of the soil where plants are grown or animals are raised. For example, researchers know that soils in the high plains of northern Nebraska and the Dakotas have very high levels of selenium. People living in those regions generally have the highest selenium intakes in the United States (U.S.). In the U.S., food distribution patterns across the country help prevent people living in low-selenium geographic areas from having low dietary selenium intakes. Soils in some parts of China and Russia have very low amounts of selenium. Selenium deficiency is often reported in those regions because most food in those areas is grown and eaten locally.

Selenium also can be found in some meats and seafood. Animals that eat grains or plants that were grown in selenium-rich soil have higher levels of selenium in their muscle. In the U.S., meats and bread are common sources of dietary selenium. Some nuts are also sources of selenium.

Selenium content of foods can vary. For example, Brazil nuts may contain as much as 544 micrograms of selenium per ounce. They also may contain far less selenium. It is wise to eat Brazil nuts only occasionally because of their unusually high selenium content. Selected food sources of selenium are provided below.

Selected Food Sources of Selenium

*DV = Daily Value. DVs are reference numbers developed by the Food and Drug Administration (FDA) to help consumers determine if a food contains a lot or a little of a specific nutrient. The DV for selenium is 70 micrograms (mcg). Most food labels do not list a food's selenium content. The percent DV (%DV) listed on the table indicates the percentage of the DV provided in one serving. A food providing 5% of the DV or less is a low source while a food that provides 10–19% of the DV is a good source. A food that provides 20% or more of the DV is high in that nutrient. It is important to remember that foods that provide lower percentages of the DV also contribute to a healthful diet. For foods not listed in this table, please refer to the U.S. Department of Agriculture's Nutrient Database Web site.

Selenium Recommended Dietary Intake

The daily recommended dietary allowances (RDAs) of selenium are:

The tolerable upper limit is:

The following selenium doses have been studied in scientific research:

BY MOUTH:

• Autoimmune thyroiditis (Hashimoto's thyroiditis): 200 mcg daily.

• In studies supporting the use of selenium for prostate cancer prevention, men took 200 micrograms daily.

Selenium Side Effects

Selenium is a trace mineral, meaning that the human body only needs a small amount to function properly. In the United States, most people get plenty of selenium through food. A normal dietary intake is unlikely to cause any side effects for most people. However, a high selenium intake (usually through supplementation) can cause serious side effects.

Serious Selenium Side Effects

Even though it seems like a harmless mineral, selenium can cause some dangerous side effects, especially if too much is taken. Although some of these side effects do not appear to be serious, they can be signs of selenium toxicity which is similar to arsenic poisoning. Because selenium toxicity can result in death, you should immediately report any of these side effects to your healthcare provider. These side effects include but are not limited to:

• Nausea, vomiting, and abdominal (stomach) pain

• White, horizontal streaking of the fingernails

• Hair loss

• Hair and nail brittleness

• A metallic taste in the mouth

• "Garlic" breath odor

• Fatigue

• Irritability

• Weight loss

• Muscle tenderness

• Shakiness

• Flushing (redness) of the face

• Heart failure

• Cardiac arrest

• Signs of an allergic reaction, such as:

• A rash

• Itching

• Hives

• Swelling of the mouth or throat

• Wheezing

• Difficulty breathing.

There is also some concern that high intakes of selenium may increase the risk of skin cancer, type 2 diabetes, and male infertility. However, more research is necessary before the full extent of these risks can be determined.

If you think you are experiencing a selenium side effect, please let your healthcare provider know. Also, let your healthcare provider know if you develop something that "just does not seem right." While it may not be a selenium side effect, your healthcare provider will be able to diagnose and treat the problem.

Selenium Safety

Selenium is LIKELY SAFE for most people when taken by mouth in doses less than 400 mcg per day, short-term.

Higher doses are POSSIBLY UNSAFE. They can cause significant side effects including nausea, vomiting, nail changes, loss of energy, and irritability. Poisoning from long-term use is similar to arsenic poisoning, with symptoms including hair loss, white horizontal streaking on fingernails, nail inflammation, fatigue, irritability, nausea, vomiting, garlic breath odor, and a metallic taste.

Selenium can also cause muscle tenderness, tremor, lightheadedness, facial flushing, blood clotting problems, liver and kidney problems, and other side effects.

There is concern that taking selenium for a long time might not be safe. Long-term consumption of selenium supplements appears to increase the chance of getting type 2 diabetes. It also seems to increase the risk of skin cancer recurrence. There is also some concern that having too much selenium in the body might increase the risk of overall death as well as death from cancer.

Precautions and Warnings

Pregnancy and breast-feeding: Selenium use is POSSIBLY SAFE during pregnancy and breast-feeding when used short-term in amounts that are not larger than 400 mcg per day.

Fertility problems in men: Selenium and other antioxidants play an essential role in how your body makes certain proteins found in sperm. Selenium might decrease the ability of sperm to move, which could reduce fertility. One study suggested that selenium supplements might improve male fertility in men who had low levels of selenium. However, high levels of selenium are associated with decreased sperm motility. Selenium might decrease the ability of sperm to move, which could reduce fertility. If you are trying to father a child, don't take selenium supplements.

A history of skin cancer: Long-term use of selenium supplements might slightly increase the risk of skin cancer recurrence, but this is controversial.

Under-active thyroid (hypothyroidism): Taking selenium can worsen hypothyroidism especially in people with iodine deficiency. In this case, you should take iodine along with selenium. Check with your healthcare provider.

Surgery: Selenium might increase the risk of bleeding during and after surgery. Stop taking selenium at least 2 weeks before a scheduled surgery.

Selenium Drug Interactions

If you are being treated with any of the following medications, you should not use selenium supplements without first talking to your health care provider.

Drugs that affect selenium levels in the body -- These drugs may lower levels of selenium:

• Cisplatin, a chemotherapy drug

• Clozapine (Clozaril)

• Corticosteroids, such as prednisone

• Valproic acid (Depakote)

Anticoagulants and antiplatelet drugs (blood thinners) -- When taken with these drugs, selenium may increase the risk of bleeding:

• Clopidogrel (Plavix)

• Warfarin (Coumadin)

• Heparin

• Aspirin

Barbiturates -- In animal tests, selenium seems to make the sedative effects of these drugs last longer:

• Butabarbital (Butisol)

• Mephabarbital (Mebaral)

• Phenobarbital (Nembutal)

• Secobarbital (Seconal)

Chemotherapy -- Although selenium may help reduce side effects from drugs such as cisplatin, doxorubicin, and belomycin, it may also interfere with their cancer-fighting ability. If you are undergoing chemotherapy, talk to your oncologist before taking selenium or any other supplement.

Cholesterol-lowering medications -- Simvastatin (Zocor) and niacin have been shown to lower LDL ("bad") cholesterol and raise HDL ("good") cholesterol in people with heart disease. Taking antioxidants, including selenium, along with these drugs may make them less effective. Theoretically, selenium may also reduce the effectiveness of other statins, including atorvastatin (Lipitor), fluvastatin (Lescol), lovastatin (Mevacor), and prevastatin (Pravachol).

Gold salts -- may lower levels of selenium in the body and cause symptoms of selenium deficiency.

Selenium Reviews

The following reviews have been selected:

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7 of 7 people found the following review helpful:

5.0 out of 5 stars Does NOT upset my stomach, September 25, 2010

By C&S Stephens (Michigan, USA)

I take Selenium for my Arthritis and ever since I started taking it my joint pain has gotten a lot better. Need to give it a few weeks up to two months to start working in your system.

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6 of 6 people found the following review helpful

Awesome! September 10, 2008

From Kentucky

Selenium is a great cancer fighter. These all natural v-caps are small and easy to take - no complaints here.

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7 of 7 people found the following review helpful

MR. September 28, 2008

From Texas

DR.WEIL RECOMMENDATION IS ANOTHER SOURCE TO HELP OUR BODY TO KEEP CLEAR OF FREE RADICALS.

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2 of 2 people found the following review helpful

Insurance March 26, 2009

By donald stephens From Washington

Selenium is short in our soil in the northwest, and sometimes in our food. Has preventive use against cancer as well. Cheap insurance for my life for a nickel a day.

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2 of 5 people found the following review helpful:

5.0 out of 5 stars Selenium can help to prevent cancer, September 19, 2011

By D. R. Schryer (Poquoson, VA United States)

Several years ago the findings of a large double-blind, placebo-controlled clinical study of selenium supplementation was published in the Journal of the American Medical Association. The multi-year study showed that people given 200 micrograms of supplemental selenium daily had only HALF the death rate from cancer as people who were given a placebo instead of selenium. No harmful side effects were observed. Has your doctor told you about this study or recommended that you take supplemental selenium to reduce your risk of cancer? I doubt it. He or she may well be unaware of this study; or, if aware, has dismissed it because it involved a simple, readily-available nutrient rather than a new wonder drug. But, if any pharmaceutical drug were available which cut the cancer death rate in half with no harmful side effects -- and none currently is -- you would see ads for it plastered on TV and magazines and your doctor would readily prescribe it for you. By the way, perhaps your doctor or a friend may tell you that selenium is toxic. Yes, it can be in large doses, but it is quite safe in the 200 microgram dosage used in the JAMA study which, as noted above, found no harmful side effects.

Two other facts are worth noting. Selenium has several beneficial effects -- including helping protect against cadmium, mercury, and lead poisoning -- in addition to helping prevent cancer. Also, supplemental vitamin D3 has been found to help prevent cancer as well as protect against colds and flu. A combination of 200 micrograms of selenium plus 5,00 I.U. of vitamin D3 daily could reduce the risk of cancer by about 75% and have other beneficial effects as well.

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2 of 2 people found the following review helpful:

5.0 out of 5 stars Selenium is a crucial nutrient, December 27, 2011

By Jeri Zerr...

After reading Dr. Joel Wallach's work with selenium and inducing cystic fibrosis in the adult primate I began to realize the important role selenium plays not just with cystic fibrosis, not just with lung and heart disease, but also connected the dots with pancreatic changes and a possible link to diabetes.

Since avoiding food chemicals including anything "bleached / enriched", brominated vegetable oils, brominated dough conditioners, high fructose corn syrup, etc my husband's Type 2 diabetes took a rapid 180 turn and finally began being under control with medication - a first in upteen years. Then when we began introducing mineral rich whole foods and naturally sourced supplements, another major improvement was achieved. Since he began taking occasional selenium supplements his cardiologist has remarked "looking at these labs I would NOT call you a diabetic" ... and he has no longer been taking ANY diabetes meds - not in almost TWO years!!

We feel Selenium was vital supplement in helping my husband Kick the Diabetes Bucket and finally lead a normal, healthy lifestyle free from the Fear Factor the diabetic counselors and medical experts had led us to believe.

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15 of 16 people found the following review helpful:

5.0 out of 5 stars A crucial trace mineral that enhances the immune system and detoxifies the body, July 17, 2011

By Kate McMurry...

Disclaimer: I offer the information below purely for the purposes of consumer education about this product. It is not intended as medical advice.

Selenium is a trace mineral that is crucial to the diet of humans and most animals. It has physical and chemical properties similar to sulfur and is found directly below sulfur on the periodic table of the elements. It is not recommended to use supplemental selenium in it its inorganic forms such as sodium selenite. Some researchers consider the most bioavailable form of selenium to be its organic form, L-selenomethionine...

L-selenomethionine can be obtained in the diet by consuming whole grains, legumes, nuts (especially Brazil nuts), meat and seafood. The most direct dietary source of L-selenomethionine is from plant food. Any L-selenomethionine in meat and fish is due to plant food that the animal consumed when alive. Selenium is found in soil all over the world, and the amount in a particular soil impacts how much selenium ends up in the food that grows in it.

Scientists first understood the nutritional importance of selenium in the late 1950's when an important study linked liver disease to low selenium in the diet. The first of many studies indicating selenium inhibits the growth of cancer came from the National Institutes of Health (NIH) in 1996. It found a 50% decrease in the incidence of lung, prostate and colorectal cancer in test subjects receiving selenium supplementation.

Subsequent research has revealed how selenium fights cancer. First, it prevents tumor growth by enhancing the body's immune system and by helping to cut off blood supply to tumors, which slows or stops their growth. Second, it has antioxidant properties. Antioxidants counteract free radicals, which are atoms within cells that lose an electron. An atom with an unpaired electron will reach out and grab a replacement electron from another atom nearby. If this process becomes widespread and unchecked in the body, it can lead to extensive biological damage at the cellular level.

Because it is an antioxidant, selenium also helps heal/prevent heart disease, particularly atherosclerosis (plaque in the arteries), and many autoimmune disorders such as arthritis, HIV and Hashimoto's thyroiditis. In addition to promoting healthy functioning of the immune system, selenium stimulates the production of prostaglandins, substances in the body which help lower blood pressure and reduce inflammation. Reducing inflammation is particularly important since many medical researchers consider it a key contributor to every major disease.

Research has also indicated that selenium chelates (removes) heavy metals from the body, particularly mercury, which is a neurotoxin. Humans are regularly exposed to mercury due to air pollution from coal-fired power plants, mercury-based vaccine preservatives, mercury-amalgam dental fillings, and mercury-tainted seafood. It also gets into the ground water due to millions of consumers sending broken electronic equipment (which contains lead, arsenic and cadmium in addition to mercury) to the city dump with their regular trash rather than disposing of it as toxic waste. Finally, compact fluorescent lamps/bulbs (CFLs) contain mercury, and many consumers do not realize they should dispose of burned-out CFLs as toxic waste and clean up broken CFLs with extreme care to avoid exposing themselves and their families to mercury. (The EPA states: "Open nearby windows to disperse any vapor that may escape, carefully sweep up the fragments [without touching them directly with] your hands, and wipe the area with a [damp] disposable paper towel to remove all glass fragments. Do not use a vacuum [because the mercury will stay in the bag, in your house, emitting fumes]. Place all fragments in a sealed plastic bag and dispose of it the same way you would other household hazardous waste [such as AA and AAA batteries] at your local Household Hazardous Waste Collection Site.")

It is important to note that even though selenium does so many great things for one's health, it does not therefore follow that one should take fistfuls of these pills. The top recommended safe dosage is 400 mcg per day, which would be two of these 200 mcg pills. I myself take only one of these pills per day.

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