Selenium Cancer Prevention

SeleniumOther Names: Atomic Number 34, Ebselen, Selenite, Selenium Dioxide, Selenized Yeast, L-Selenomethionine, Selenomethionine, Sodium Selenite.

Selenium can assist in a holistic cancer treatment. Selenium will not cure cancer alone but in combination with other herbs, juices and therapies, selenium will boost cancer treatment effectiveness.

Research shows that Selenium, especially when used in conjunction with vitamin C, vitamin E and beta-carotene, works to block chemical reactions that create free radicals in the body. Selenium also helps stop damaged DNA molecules from reproducing. In other words, Selenium acts to prevent tumors from developing. According to Dr. James Howenstine in A Physician’s Guide to Natural Health Products That Work, Selenium contributes towards the death of cancerous and pre-cancer cells. Dr. Howenstine further states that the death of the cancer cells appear to occur before they replicate, thus helping stop cancer before it gets started.

In addition to preventing the onset of disease, Selenium has also been shown to aid in slowing cancer’s progression in patients that already have it. A 1996 study by Dr. Larry Clark of the University of Arizona showed how effective Selenium can be in preventing cancer. In the study of 1,300 old 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 Selenium were cut almost in half, according to the study that was published in the Journal of the American Medical Association. While the study concluded that Selenium helped protect against all types of cancer, it had particularly powerful impacts on prostate, colorectal, and lung cancers. Jean Carper, in Miracle Cures, called Dr. Clark’s findings an unprecedented cancer intervention study that bumped up the respectability of using supplements against cancer several notches.

There are several possible mechanisms for the protective effect of Selenium. Selenium activates an enzyme in the body called gluthathione peroxidase that protects against the formation of free radicals which is important in preventing cancer and cardiomegaly (enlargement of the heart that causes premature aging) and early death. In this situation, Selenium may work interchangeably (and in synergy) with vitamin E. In test tube studies, Selenium inhibited tumor growth and regulated the natural life span of cells, ensuring that they died when they were suppose to instead of turning “immortal” and hence malignant. Because of this particular action, the University of Arizona researchers say that Selenium could be effective within a fairly short time frame.

At the Yunnan Tin Corporation in China there is a very high rate of lung cancer among the miners. Forty healthy miners were given Selenium supplements for a year. The Selenium, which increased in their blood, boosted a key detoxifying enzyme system while simultaneously decreasing dangerous lipid peroxide levels by nearly 75%. It also protected against cancer-causing substances and ultraviolet radiation. Doctors at the Chinese Academy of Medical Sciences concluded that selenium supplements were a safe and effective food supplement for people.

In a recent five-year study of nearly 30,000 rural Chinese people, researchers from the National Cancer Institute found that daily doses of these three nutrients reduced cancer deaths by 13%. In another study it was found that a daily intake of 200 micrograms of Selenium cut the incidence of prostate cancer by 60 percent. Similar associations have been found with leukemia, as well as cancers of the intestines, rectum, ovary, prostate, lung, pancreas, skin and bladder. In Yugoslavia, scientists studied 33 patients with breast cancer. These women had Selenium levels in their bloodstream only half of those of healthy volunteers.
Selenium Supplement
In 1976, Dr. Raymond Shamberger pointed out that the cities and states with high Selenium content in the soil also had significantly lower rates of cancer, especially of the digestive and urinary systems. Dr. Shamberger was among the first to discover the link between low Selenium content in the soil and increasing number of deaths from cancer. Accordingly, geography can have a significant impact on diet. In Antioxidants Against Cancer, author Ralph Moss, says one theory for why cancer rates are so high in Linxian, China, dubbed the World Capital of Cancer, is that the soil is deficient in the essential minerals selenium and zinc. In Earl Mindell’s Supplement Bible, he suggested that part of the reason American men are five times more likely than Japanese men to die from prostate cancer could be because, in general, “the Asian diet contains four times the amount of Selenium as the average American diet.”

Although too much Selenium can actually be toxic to the system, research indicates the majority of the population is not getting enough of the essential mineral. So, how can we up our intake of Selenium and help our bodies fight cancer? The good news is there are some good dietary sources of Selenium: Mushrooms, egg yolks, seafood, poultry and kidney, liver and muscle meats contain the mineral. Vegetables as well as whole grains and seeds can also be good sources of Selenium. Strange as it may seem, toenail levels of Selenium are considered a good indicator of long-term Selenium intake. They found that the people whose toenails had the highest levels of Selenium had half of the rate of lung cancer compared with those whose toe-nails were low in Selenium.

However, because the amount of Selenium in vegetables and grains depend on the Selenium content in the soil in which they are grown, it can be hard for average consumers to know how much of the mineral they are actually getting in their diets. “The Selenium content of food is largely dependent on the content of volcanic ash in the soil on which the food was grown, with higher volcanic ash content yielding higher Selenium levels. Soil that is irrigated by seawater, such as much of California’s cropland, also contains higher levels of Selenium,” says Sue Gebo in What’s Left to Eat. Gebo adds that, in general, soil in the western United States is richer in Selenium than soil in the eastern part of the country.

Another reason it seems to be difficult for Americans to get enough Selenium is the process food undergo before they make it onto grocery store shelves. Mindell points out, for example, that processing wheat into white flour strips it of a great deal of its Selenium content.

One way to get more Selenium in your diet might be to eat more organically grown foods, which some studies have shown to contain more selenium as well as higher levels of beta carotene and vitamin E. Perhaps a more surefire way to boost your Selenium intake is to add supplements to your diet. Mindell advocates the use of supplements, saying, “To me, taking Selenium supplements, in addition to eating Selenium-rich foods, is good insurance against disease.” However, for those who oppose taking pills, Dr. Andrew Weil in Ask Dr. Weil says eating just one shelled Brazil nut, grown in the Selenium-rich soil of central Brazil, provides 120 micrograms of the mineral, getting you that much closer to the daily target of 200 micrograms.

Selenium is also found to make chemotherapy safer and more effective. According to the Life Extension Foundation, the use of Selenium during chemotherapy in combination with vitamin A and vitamin E can reduce the toxicity of chemotherapy drugs. The mineral also helps “enhance the effectiveness of chemo, radiation, and hyperthermia while minimizing damage to the patient’s normal cells; thus making therapy more of a selective toxin,’” says Patrick Quillin in Beating Cancer with Nutrition.

Selenium Historical Medical Usage

Selenium was first used in conventional medicine as a treatment for dandruff. It was first discovered in 1817 and because of its silvery color, was named for Selene, the ancient goddess of the moon.

Selenium is used for diseases of the heart and blood vessels, including stroke and atherosclerosis (hardening of the arteries). Some people use selenium for under-active thyroid, osteoarthritis, rheumatoid arthritis (RA), macular degeneration, hay fever, infertility, cataracts, gray hair, abnormal pap smears, chronic fatigue syndrome (CFS), mood disorders, arsenic poisoning, and preventing miscarriage.

Selenium is also used for preventing serious complications and death from critical illnesses such as head injury and burns. It is also used for preventing bird flu and treating HIV/AIDS.

Selenium Health Benefits

  • Enhances Chemotherapy Effectiveness
  • Minimizes Chemotherapy Toxicity
  • Repairs DNA Damage
  • Anti-proliferative
  • Antibacterial
  • Anti-fungal
  • Antiviral
  • Anti-carcinogen
  • Boosts Cardiovascular Health
  • Prevents Toxic Metal Poisoning
  • Prevents Skin Damage
  • Prevents Male Infertility
  • Protects Against Free Radicals
  • Protects Against Mutagens
  • Reduces Insulin Resistance
  • Prevents Rectal Cancer
  • Prevents Ovarian Cancer
  • Prevents Cervical Cancer
  • Prevents Leukemia
  • Prevents Breast Cancer
  • Prevents Prostate Cancer
  • Prevents Heart Disease
  • Prevents Colorectal Cancer
  • Prevents Esophageal Cancer
  • Prevents Stomach Cancer
  • Prevents Miscarriage
  • Treats Rheumatoid Arthritis
  • Treats Diabetes
  • Treats HIV/AIDS
  • Treats Osteoarthritis
  • Treats Atherosclerosis
  • Treats Macular Degeneration
  • Treats Hay Fever
  • Treats Cataracts
  • Treats Chronic Fatigue Syndrome
  • Treats Bird Flu
  • Reduces Gray Hair
  • Helps Mood Disorders
  • Reduces swelling after surgery

Though there are studies to support these health benefits, there are no definite conclusions. Some of the studies contradict each other and some needs more evidence.

The following list shows some of the foods that have Selenium:

  • Brewer’s Yeast
  • Wheat Germ
  • Butter
  • Garlic
  • Grains
  • Sunflower Seeds
  • Walnuts
  • Raisins
  • Liver
  • Kidneys
  • Shellfish
  • Fish
  • Mushrooms
  • Egg Yolks
  • Seafood
  • Poultry
  • Kidney, Liver and Muscle Meat
  • Onions
  • Broccolli
  • Asparagus
  • Tomatoes

Selenium Precaution

Very high doses of Selenium can be toxic. There is no question that excess Selenium in the soil (in the form of its compounds, selenite or selenate) can kill grazing animals and could probably in sufficiently large doses kill humans as well. The symptoms of Selenium poisoning are readily apparent. These symptoms include a heavy garlic odor, pallor, nervousness, depression, a metallic taste, skin eruptions, irritability, discolored teeth, hair loss, nail loss, and nausea. Selenium can also cause muscle tenderness, tremor, lightheadedness, facial flushing, blood clotting problems, liver problems, kidney problems, and other side effects.

Moreover, there is concern that taking Selenium for a long time might not be safe. Long-term consumption of Selenium supplements appear 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.

Taking Selenium may also worsen hypothyroidism especially in people with iodine deficiency. In this case, you should take iodine along with Selenium.

There is, however, some doubt about Selenium carcinogenicity studies. For instance, one study showed toxic effects for inorganic, but not organic, forms of the mineral.

Selenium Interactions

Certain metals such as lead, cadmium, arsenic, mercury, and silver block the action of Selenium. Recent laboratory experiments have shown that high doses of zinc block the action of Selenium. In some experiments, dietary zinc exceeding nutritional requirements has been shown to suppress chemically induced tumors in rats and hamsters, but when given in drinking water it counteracts the protective effect of Selenium in mice. Since Selenium has a wide spectrum of demonstrable anticancer effects, cancer patients should be particularly cautious with zinc, since it is a Selenium antagonist. Therefore, one has to be careful about taking excessive amounts of zinc (over 20 milligrams per day from diet and supplements) while taking Selenium at the same time.

Do not take Selenium with medications that slow blood clotting (Anticoagulants/Antiplatelets). Taking Selenium along with this type of medication might increase the chances of bruising and bleeding. Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, ticlopidine (Ticlid), warfarin (Coumadin), and others.

Taking Selenium, beta-carotene, vitamin C, and vitamin E together might also decrease the effectiveness of some medications used for lowering cholesterol (Statins). It is not known if Selenium alone decreases the effectiveness of medications used for lowering cholesterol. Some medications used for lowering cholesterol include atorvastatin (Lipitor), fluvastatin (Lescol), lovastatin (Mevacor), and pravastatin (Pravachol). The same combination may also decrease the beneficial effects of niacin.

Selenium might also slow how fast the body breaks down sedative medications (Barbiturates). Taking Selenium with these medications might increase the effects and side effects of these medications.

Gold salts bind to Selenium and decrease Selenium in parts of the body. This might decrease the normal activity of Selenium, possibly resulting in symptoms of Selenium deficiency. Gold salts include aurothioglucose (Solganal), gold sodium thiomalate (Aurolate), and auranofin (Ridaura).

Some research shows that women who take birth control pills might have increased blood levels of Selenium. But other research shows no change in Selenium levels in women who take birth control pills. There isn’t enough information to know if there is an important interaction between birth control pills and Selenium.

Some species of astragalus may accumulate large amounts of Selenium, especially when grown in Selenium-rich soils. Taking products made from these plants along with Selenium supplements could cause Selenium poisoning. However, most astragalus supplements contain Astragalus membranaceus, which is not a Selenium accumulator.

Selenium Dosage

Daily Recommended Dietary Allowances (RDAs) of Selenium

  • Children 1-3 years, 20 mcg
  • Children 4-8 years, 30 mcg
  • Children 9-13 years, 40 mcg
  • People over 13 years, 55 mcg
  • Pregnant women, 60 mcg
  • Lactating women, 70 mcg
  • Infants up to 6 months old, 2.1 mcg/kg is adequate intake (AI)
  • Infants 7-12 months, 2.2 mcg/kg per day is adequate intake (AI)

Some studies also recommend a daily selenium intake of 200 micrograms while the National Academy of Sciences recommend only 150 micrograms of selenium per day. From a compilation of available data, the maximum tolerable level for selenium in man could be considered in the range of 1000 to 1500 micrograms/day in contrast with other studies that recommend a selenium human tolerable level of 500 micrograms/day. The amount of selenium that can be tolerated, however, is dependent upon individual biological variation, nutritional status, and general state of health.

Keep in mind that selenium can be toxic in high doses. Experts warn that too much selenium intake, especially from supplements, is unsafe. Stay safe and follow the recommended dosage above.

Selenium Products

Selenium Supplements

Selenium Research Links

Effects of selenium supplementation for cancer prevention in patients with carcinoma of the skin. A randomized controlled trial. Nutritional Prevention of Cancer Study Group.
Decreased incidence of prostate cancer with selenium supplementation: results of a double-blind cancer prevention trial.
The protective role of selenium on genetic damage and on cancer.
Selenium compounds have disparate abilities to impose oxidative stress and induce apoptosis.
Selenium and interleukins in persons infected with human immunodeficiency virus type 1.
Selenium from high selenium broccoli protects rats from colon cancer.
Interactions of selenium compounds with other antioxidants in DNA damage and apoptosis in human normal keratinocytes.
Study of prediagnostic selenium level in toenails and the risk of advanced prostate cancer.
Serum selenium and subsequent risk of prostate cancer.
Plasma selenium level before diagnosis and the risk of prostate cancer development.
Chemoprevention of DMBA-Induced Mammary Tumors in Rats by a Combined Regimen of Alpha-Tocopherol, Selenium, and Ascorbic Acid.
Selenium in the maintenance and therapy of HIV-infected patients.
Selenium deficiency is associated with shedding of HIV-1–infected cells in the female genital tract.
Baseline characteristics and the effect of selenium supplementation on cancer incidence in a randomized clinical trial: a summary report of the Nutritional Prevention of Cancer Trial.
Cancer-protective properties of high-selenium broccoli.
Serum levels of selenium, manganese, copper, and iron in colorectal cancer patients.
Urinary selenium excretion in patients with cervical uterine cancer.
Chemoprevention of colon cancer by a glutathione conjugate of 1,4-phenylenebis(methylene)selenocyanate, a novel organoselenium compound with low toxicity.
Selenium supplementation and lung cancer incidence: an update of the nutritional prevention of cancer trial.
Association between alpha-tocopherol, gamma-tocopherol, selenium, and subsequent prostate cancer.
Selenium supplementation and secondary prevention of nonmelanoma skin cancer in a randomized trial.
Risk of squamous cell carcinoma of the skin in relation to plasma selenium, alpha-tocopherol, beta-carotene, and retinol: a nested case-control study.
Synergistic effect of vitamin E and selenium in human prostate cancer cell lines.
Anticarcinogenic effects of selenium.
A prospective study of plasma selenium levels and prostate cancer risk.
Selenium supplementation, baseline plasma selenium status and incidence of prostate cancer: an analysis of the complete treatment period of the Nutritional Prevention of Cancer Trial.
Selenium as an element in the treatment of ovarian cancer in women receiving chemotherapy.
Interaction of vitamin C and selenium supplementation in the modification of mammary carcinogenesis in rats.
Selenium for alleviating the side effects of chemotherapy, radiotherapy and surgery in cancer patients.
Effect of selenium and vitamin E on risk of prostate cancer and other cancers: the Selenium and Vitamin E Cancer Prevention Trial (SELECT).
Serum selenium levels and all-cause, cancer, and cardiovascular mortality among US adults.
The two faces of selenium-deficiency and toxicity–are similar in animals and man.

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