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19/09/2007

Selenium and health

Selenium is a potent immune stimulator – the most potent immune stimulator of all some think. Selenium is an essential component of thyroid metabolism and antioxidant defense, as well as immune function. It may improve activation and proliferation of B- lymphocytes and enhance T-cell function.[i] Selenium is essential for our immune system to function at optimal performance. Thus we should not be surprised to find out those cancer patients with low selenium levels tend to have a wider spread of the disease, more recurrences and die sooner. [ii]

Blood selenium levels often indicate the presence
of cancer and even the severity of cancer in a patient.

Selenium influences both the innate, "nonadaptive" and the acquired, "adaptive" immune systems[iii]-[iv]-[v]-[vi]-[vii] The innate immune system includes barriers to infection and nonspecific effector cells such as macrophages. Both the T and B lymphocytes form the major effector cells of the acquired system that mature with exposure to immune challenges. Selenium-deficient lymphocytes are less able to proliferate in response to mitogen, and in macrophages, leukotriene B4 synthesis, which is essential for neutrophil chemotaxis, is impaired by this deficiency. These processes can be improved by selenium supplementation. The humoral system is also affected by selenium deficiency; for example, IgM, IgG and IgA titers are decreased in rats, and IgG and IgM titers are decreased in humans. In endothelial cells from asthmatics, there is a marked selenium deficiency that results in an increase in expression of adhesion molecules, which causes greater adhesion of neutrophils.[viii]

Selenium is also involved in several key metabolic activities through its selenoprotein enzymes that protect against oxidative damage.[ix] Further, selenium deficiency may allow invading viruses to mutate and cause longer-lasting, more severe illness.[x] Animal research has shown selenium and vitamin E have synergistic effects, enhancing the body’s response to bacterial[xi] and parasitic infections.[xii]

Proving the point that selenium is a potent immune stimulator is a 18-month study of 262 patients with AIDS found those who took a daily capsule containing 200 micrograms of selenium ended up with lower levels of the AIDS virus and more health-giving CD4 immune system cells in their bloodstreams than those taking a dummy pill. These AIDS patients who took selenium were able to suppress the deadly virus in their bodies and boost their fragile immune systems, adding to evidence that selenium has healing powers we need to pay attention to in treating cancer patients.[xiii] Those with severely compromised immune systems due to AIDS had dramatically better immune system response with selenium supplementation and this finding is consistent with the information presented by the NIH on their selenium web site.

As an antioxidant nutrient, selenium prevents the action of free radicals which are believed to be causative agents behind degenerative diseases such as premature ageing, cancer and atherosclerosis.[xiv] Clinical trials have also indicated that selenium can have a role to play in combating oxidative diseases[xv], enhancing the immune response[xvi], increasing male fertility[xvii], improving psychological mood scores[xviii] and reducing the pain and stiffness in arthritis sufferers.[xix]

The implicit importance of selenium to human health is
recognised universally. Selenium is incorporated as
selenocysteine at the active site of a wide range of selenoproteins.

Dr. Emanuel Revici, a Romanian-born physician, scientist, author, and humanitarian[xx] had five major papers on lipids, pain, and cancer deposited by the Pasteur Institute into the eminent National Academy of Sciences during the Second World War. By 1948, Revici had begun exploring the use of selenium in treating cancer and as a means for rendering radiation less harmful. Dr. Revici's use of selenium in the treatment of cancer predates mainstream interest in this mineral by more than twenty years. Selenium is one of the major trace elements always found deficient in cancer-prone populations. Research has shown that it is of value not only in preventing cancer but also in treating it.[xxi]

Revici uses a special molecular form of selenium (bivalent-negative selenium) incorporated in a molecule of fatty acid. In this form, he can administer up to 1 gram of selenium per day, which corresponds to 1 million micrograms per day, reportedly with no toxic side effects. In contrast, too much selenite (hexavalent-positive selenium) has toxic effects on animals, so human intake of commercial selenite is limited to a dosage of only 100 to 150 micrograms by mouth. Dr. Revici often administered his nontoxic form of selenium by injection, usually considered to be four times more powerful than the form given orally.

Dr. Gerhard Schrauzer, professor of biochemistry at the University of California at La Jolla , publicly credited Revici for “having discovered pharmacologically active selenium compounds.” Dr. Gerhard Schrauzer noted almost 30 years ago if every woman in America took 200 micrograms of supplementary selenium daily that breast cancer rates would rapidly decline in the space of a few short years. Dr. Schrauzer is professor emeritus from the University of California , San Diego School of Medicine and has chaired two world conferences on selenium and cancer.

Dr. Richard Donaldson of the St. Louis Veterans' Administration Hospital conducted a clinical trial with terminally ill cancer patients. He found that when he could raise the patients' blood levels of selenium into the normal range, their pain and tumor sizes were often reduced. In a 140 patient study of cancer victims treated with selenium, Dr. Donaldson reported in 1983 that some patients deemed terminal with only weeks to live were completely free of all signs of cancer after four years; all the patients showed a reduction in tumor size and in pain.[xxii]

The amount of selenium needed to obtain normal blood levels varied from person to person. Normal healthy people usually were seen to have normal blood selenium levels on normal diets however it seemed that cancer patients had lower selenium levels on similar diets. (As we will see below this could in great part be due to more intense mercury toxicity in cancer patients.) Apparently they could not get enough without supplements. Dr. Donaldson found that he had to supplement the cancer patients with at least 200 to 600 micrograms of selenium per day and in some cases 2,000 micrograms of selenium per day were required to obtain normal blood selenium levels.

There are now seven population studies in the past six years
that examined the possible connection between selenium and
prostate cancer. All but one of them has found selenium protective.
Karen Collins, R.D.

A 1996 study by Dr. Larry Clark of the University of Arizona showed just how effective selenium can be in protecting against cancer. 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, according to the study that was published in the Journal of the American Medical Association on December 25, 1996. In addition, the people who had taken selenium had 63 percent fewer prostate cancers, 58 percent fewer colorectal cancers, 46 percent fewer lung cancers and overall 37% fewer cancers. Selenium was found to reduce the risk of lung cancer to a greater degree than stopping smoking.[xxiv]

One important study found that high blood levels of selenium is associated with a four- to fivefold decrease in the risk of prostate cancer. Scientists at Stanford University studied 52 men who had prostate cancer and compared them to 96 men who didn’t.[xxvi] One surprising finding was that blood levels of selenium generally decreased with age. It is well known that the risk of prostate cancer increases dramatically as one ages.

Those who have studied geographical differences have seen that in low-selenium regions, higher death rates occurred from malignant lymphomas and cancers of the tongue, esophagus, stomach, colon, rectum, liver, pancreas, larynx, lung, kidneys and bladder. Dr. Harold Foster has stated that death rates in the USA for breast, colon, rectal and lung cancer are lower when blood selenium levels are high. Dr. Foster is the one to have reported that cancer patients with low selenium levels tend to have a wider spread of the disease, more recurrences and die sooner.[xxvii] This is critical information that fits rationally into the entire picture of selenium being compiled by medical science and is the principle reason I list selenium as the number four agent in our cancer protocol.

There is no doubt that selenium is essential for human health and that these elements may protect against cancer and other diseases. For this reason people in regions which are naturally rich in selenium tend to live longer. 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 binds strongly with mercury protecting us from its damaging effects.

Dr. Laura Raymond and Dr. Nicholas Ralston of the University of North Dakota tell us that, “Measuring the amount of mercury present in the environment or food sources may provide an inadequate reflection of the potential for health risks if the protective effects of selenium are not also considered. Owing to the extremely high affinity between mercury and selenium, selenium sequesters mercury and reduces its biological availability. It is obvious that the converse is also true; as a result of the high affinity complexes formed, mercury sequesters selenium. This is important because selenium is required for normal activity of numerous selenium dependent enzymes.”[xxix]

Glutathione happens to be the most important of these selenium dependent enzymes. Mercury is highly toxic but mercury’s toxic ruin varies greatly with selenium and glutathione levels. These are the key variables that determine the harm done or the power each individual has to escape the poisonous effect of mercury and other dangerous toxins in the environment. Our defensive shields against both acute and chronic exposure to mercury depend very much on selenium and glutathione.

Selenium is useful as a controlling agent for
mercury, which attacks insulin and its binding sites.

An excess of a toxic metal and/or a relative deficiency of a nutritional
element can be found as significant contributors to every disease.
Dr. Garry Gordon

High doses of vitamin C (over 1 gram ) may reduce the
absorption of selenium. This mineral is best taken one hour
before or 20 minutes after taking vitamin C supplements.[xxxii]

Selenium deficiency impairs thyroid hormone metabolism by inhibiting the synthesis and activity of the iodothyronine deiodinases, which convert thyroxine (T4) to the more metabolically active 3,3'-5 triiodothyronine (T3). In rats, concurrent selenium and iodine deficiency produces greater increases in thyroid weight and plasma thyrotrophin than iodine deficiency alone, indicating that a concurrent selenium deficiency could be a major determinant of the severity of iodine deficiency.[xxxiii]

Later studies showed that serum T4 was maintained at control levels when both dietary iodine and selenium were low, but not when iodine alone, or selenium alone, was low. Activity of thyroidal GSH-Px (erythrocyte glutathione peroxidase) was lowest in rats fed a diet containing high iodine and low selenium. The results suggested that high iodine intake, when selenium is deficient, may permit thyroid tissue damage as a result of low thyroidal GSH-Px activity during thyroid stimulation. A moderately low selenium intake normalized circulating T4 concentration in the presence of iodine deficiency. [xxxiv]

Selenium is also essential for the production of estrogen sulfotranserfase which is the enzyme which breaks down estrogen. A deficiency of selenium can thus lead to excessive amounts of estrogen, which may depress thyroid function, and also upset the progesterone-estrogen balance. Animal studies have shown that the addition of selenium supplementation will alleviate the effects of excess iodine intake.[xxxix] Iodine and selenium deficiencies must both be resolved for iodine treatment to be effective.

For magnesium to be retained inside cells you need good antioxidant status. Selenium is the main mineral antioxidant. Foods are unreliable because food content is dependent on soil levels of selenium. Foods rich in selenium include whole grains, organ meats, butter, garlic and onion. Seafoods are rich in selenium and obviously not dependent on soil levels.

Dr. Majid Ali and Dr. Omar Ali write, “Deficiency of selenium and chromium are established risk factors of IHD. Selenium-dependent antioxidant systems are important parts of human antioxidant enzyme systems, especially in the regeneration of glutathione and other thiol antioxidants. An association between low serum selenium levels and atherogenesis, lipid peroxidation in vivo, and progression of carotid atherosclerosis has been reported. Salonen et al. observed that selenium deficiency was associated with an excess risk of myocardial infarction as well as morbidity and mortality from other expressions of coronary artery disease and other variants of cardiovascular disease in Eastern Finland . In this study, cardiovascular death and myocardial infarction were associated with low serum selenium levels in a matched-pair longitudinal study. Chromium supplementation in patients with type II diabetes results in improved glucose tolerance, lower total cholesterol and triglycerides levels and higher HDL cholesterol levels.”[xl]

Selenium in its inorganic form is poorly absorbed by the body. Most of the body’s selenium comes from organic sources, where selenium is bonded with sulphur-containing amino acids, the commonest being L-selenomethionine. Many nutritional supplements contain the poorly absorbed inorganic selenium. Selenium formulations containing L-selenomethionine are good choices but the ideal delivery system is provided by spirulina and perhaps by yeasts and even now by probiotics. (This is an area the IMVA is dedicated to studying.) When spirulina is grown in ponds with selenium added, the spirulina absorbs the inorganic selenium transforming it into organic selenium. The selenium becomes protein bonded to the amino acids in spirulina, which are present in abundance.

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