- Selenium Proves itself as Powerful Anti-Cancer Medicine
- Selenium makes Chemotherapy safer, more Effective
- Food sources of selenium
- Selenium Mechanisms
- Selenium Dosage/Administration
One of the most effective naturally occurring weapons against cancer is, like most healthy things, something many of us are not getting enough of. The mineral selenium has been shown in multiple studies to be an effective tool in warding off various types of cancer, including breast, esophageal, stomach, prostate, liver and bladder cancers. Not many people get the recommended dose of 200 micrograms a day. Most Americans only get between 60 and 100 micrograms of selenium daily from dietary sources, according to the Life Extension Foundation's Disease Prevention and Treatment. That means daily supplements might be worth considering.
Selenium was first used in conventional medicine as a treatment for dandruff, but our understanding of the mineral has come a long way since then. Today, research shows 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 (which can damage DNA and cause degenerative change in cells, leading to cancer)
Selenium also helps stop damaged DNA molecules from reproducing. In other words, selenium acts to prevent tumors from developing. "It contributes towards the death of cancerous and pre-cancer cells. Their death appears to occur before they replicate, thus helping stop cancer before it gets started," says Dr. James Howenstine in A Physician's Guide to Natural Health Products That Work.
Selenium makes Chemotherapy safer, more Effective
In addition to preventing the onset of the disease, selenium has also been shown to aid in slowing cancer's progression in patients that already have it. 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.
While the study concluded the mineral 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."
Food Sources of Selenium
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 -- garlic, onions, broccoli, asparagus, tomatoes and others -- as well as whole grains and seeds can also be good sources of selenium.
However, because the amount of selenium in vegetables and grains depends 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.
Accordingly, geography can have a significant impact on diet. In Antioxidants Against Cancer, author Ralph Moss PhD, 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, Earl Mindell RPh PhD, suggests 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."
Another reason it seems to be difficult for Americans to get enough selenium is the processing many of our foods go through 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. 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. These two work together with selenium in cancer prevention, according to Alternative Medicine author Burton Goldberg.
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.
Although extremely high doses of selenium can have toxic effects, most people are not at risk for such an overdose, and could, in fact, use more of the mineral. Simply adding more selenium-rich foods, such as organically grown vegetables and fruits to your diet, along with supplements, can help reduce your risk of cancer. And another positive side effect of selenium, according to Eat and Heal, by the Editors of FC&A Medical Publishing, is that it can actually improve your mood. Those editors write, "People who don't eat enough selenium-rich foods tend to be grumpier than people with a high dietary intake, according to recent research." So, go ahead and crack a Brazil nut open and smile.
Selenium Mechanisms
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—those loose molecular cannons that can damage DNA. 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 supposed 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.
Numerous studies suggest that an inverse association exists between selenium levels and cancer incidence (Hocman, 1988; Willett and Stampfer, 1986; Milner, 1985). Associations appear to be particularly strong with cancers that are also associated with high-fat, low-fiber diets (i.e., breast, colon, prostrate, etc.). The mechanism for selenium's reported protective effects is likely due to its function in antioxidant synthesis. Glutathione peroxidase, the primary enzyme that converts hydrogen peroxide to water (and thus prevents lipid peroxidation) is selenium-dependent. Inhibition of lipid or bile acid oxidation may account for its protective role (reviewed by Linder 1991:496-7). Selenium may also act as an immune stimulant. Selenium deficiency inhibits macrophage-mediated tumor destruction, and inhibits tumor necrosis factor-alpha production in animals (Kiremidjian-Schumacher et al., 1992).
Dietary supplementation with selenium produced the opposite effects.
The safest antioxidants are vitamin C, vitamin E, selenium, and beta-carotene. Together, they block the chemical reactions that create free radicals, which can damage DNA and promote a variety of degenerative changes in cells. Chemotherapy and radiation generate free radicals; that is how they kill dividing cells.
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 percent. 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.
Numerous mechanisms have been explored to explain the modulation of carcinogenesis by selenium (Medina 1986, El-Bayoumy 1991). The best characterized function of selenium in mammalian cells is as a component of the seleno- enzyme, glutathione peroxi-dase. This enzyme is localized in the cytosol and mitochondrial matrix, and it eliminates organic peroxides from the cell (Medina 1986). However, available evidence suggests that the prevention of carcinogenesis by selenium is not related to its function in glutathione peroxidase (Medina 1986). Other seleno- proteins have been identified, but their impact on carcinogenesis is not defined (Medina 1986). There is some evidence that selenium may alter the metabolism of carcinogens or the interaction of chemical carcinogens with DNA, but there is considerable controversy in the literature (Medina 1986). Additional mechanistic studies suggest that selenium may alter cell proliferation and/or immunologic responses (Medina 1986, El-Bayoumy 1991). Further research is needed to understand the mechanisms whereby selenium prevents cancer.
Selenium is needed to produce glutathione peroxidase, an antioxidant enzyme that protects the body from free radical damage. It is also important in preventing cancer and cardiomegaly an enlargement of the heart that causes premature aging and early death.
The best known functions of selenium at nutritionally adequate, but not at excessive, levels are its role as a part of the enzyme glutathione peroxidase and its interaction with heavy metals. Glutathione peroxidase destroys hydroperoxides and lipoperoxides, thereby protecting the constituents of the cells against free radical damage. Ip and Sinha (1981) have shown that selenium, through its function in glutathione peroxidase, could well be involved in protecting against cancer induced by high intakes of fat, especially polyunsaturated fatty acids.
Glutathione peroxidase activity in human blood increases with increasing selenium intakes, but reaches a plateau at intakes well below those customary in the United States (Thomson and Robinson, 1980). Thus, if the antitumorigenic effect of selenium is mediated through its function in glutathione peroxidase, attempts to increase the enzyme activity by selenium supplementation, superimposed on an adequate diet in the United States, would not be successful. The second function of selenium is to protect against acute and chronic toxicity of certain heavy metals. Although selenium is known to interact with cadmium and mercury, the mechanism of action is not known. Selenium does not cause an increased elimination of the toxic elements, but, rather, an increased accumulation in some nontoxic form (National Academy of Sciences, 1971). It is conceivable that carcinogenic effects of these, and perhaps other heavy metals, could be counteracted by selenium, in a manner similar to its protection against their general toxicity.
Selenium's main function in the body is to convert hydrogen peroxide to water, which is important for cellular health. Herbal Medicine Healing Cancer by Donald R Yance Jr, page 193 All of the body's tissues contain selenium, but it is most plentiful in the liver, kidneys, spleen, pancreas, and testes. Selenium works synergistically with vitamin E to protect tissues and cell membranes, aid in the production of antibodies, and help maintain a healthy heart and liver Prescription For Dietary Wellness by Phyllis A Balch, page 44
Selenium Dosage/Administration
It has been reported that selenium doses of about 250-300 micrograms a day (diet and supplements) would be helpful in preventing cancer. If an average person consumes 125 to 150 micrograms of selenium a day, an additional supplemental amount of 100 micrograms is unlikely to produce any major side effects.
Recommendation : Take selenium aspartate in a dose of 100 to 200 micrograms daily..
Selenium is a mineral with anticancer activity. But the anticancer effects of selenium are greatly reduced when there is an insufficient intake of vitamin E. Rats who receive a normal amount of vitamin E in their diets showed a 45 percent decrease in tumors when they were given selenium. But they only had a 25 percent decrease if their diet was low in vitamin E. In fact, vitamin E was considered more important than selenium in decreasing "oxidant stress" to the fat of the breast.
In the treatment of cancer the dosage is generally about 10,000 micrograms, still nearly one hundred times the National Academy of Science's recommended dose. Revici's treatment is more complicated than just organic selenium. He only uses selenium in patients whom he deems to be in a "catabolic," as opposed to an "anabolic," state. He has devised a number of urine tests to find whether a patient is in one condition or the other. Selenium is given when the urine has a low specific gravity, a high surface tension and a pH above 6.0. The alkalinity of the urine is supposed to reflect the state of the body's defenses against tumors.
Selenium levels show a U-shaped correlation with prostate cancer. In other words, both low and high blood levels of selenium increase risk. This simply means that we need enough selenium to maintain good health, yet too much can be dangerous. A practical compromise is to use a supplement that provides 100 I.U. of vitamin E (up to 400 I.U. would be fine), and about 50 micrograms of selenium.
Unlike selenomethionine, which is incorporated into protein in place of methionine, SMSC is not incorporated into any protein, thereby offering a completely bioavailable compound. In animal studies, SMSC has been shown to be 10 times less toxic than any other known form of selenium. The recommended dose of Se-methylselenocysteine (SMSC) is 200-400 mcg a day for cancer patients.
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