SELENIUM: AN ESSENTIAL TRACE MINERAL
by Lynn Hinderliter, CN, LDN
In the 1990s there was a great deal of heightened interest generated in a comparatively little known trace mineral named Selenium. Holistic Health Professionals have known for some time that selenium plays a part in the antioxidant enzyme Glutathione Peroxidase, (whence its abbreviation, SeGPX) which is arguably the most important factor in resistance to free radical damage at the cellular level. Therefore, low levels of selenium have been implicated in most chronic disease states, to include cancer, premature aging, cataracts, AMD, cardiovascular disease, osteoarthritis and more.
The research, however, left little doubt as to the extreme importance of paying attention to selenium levels in the diet.
A case in point: in the 1970s, it was discovered that those suffering from a form of juvenile heart disease called Keshan (after a Chinese county), which was characterized in children between 2 and 10 by heart enlargement, heart weakness and irregular rhythm, and fluid on the lungs, had the lowest levels of selenium in their tissues of anywhere in the world!
Supplementing with selenium considerably reduced incidences of the disease, though a possible viral connection meant that not all sufferers responded. This would tie into research done in the 1980s and 1990s, which suggests that viruses become more dangerous where a selenium deficiency exists.
One very important fact about trace minerals is that if they are not present in the soils where foods are grown, then they will not be present in the food.
The food crops will grow normally, the animals to whom they are fed will develop normally, but they are not dependent on selenium for health, we are: and we will not be getting it! Interestingly, about 50% of the land mass in the U.S. is either deficient in, or barely at the acceptable level for, selenium. It is therefore obvious that the food chain is going to be a somewhat unreliable source for a steady supply of this important element.
How important? Avian flu heightened interest in research showing that more virulent viruses develop in selenium deficient hosts
Many new viruses, together with ever more deadly versions of old diseases, are first found in developing countries, which also suffer from extensive nutritional deficiencies.
Put this together with research from the University of N. Carolina, which discovered both that mice deficient in selenium became seriously ill with lung infections when infected only with a minor flu strain, and were subsequently found to have developed several viral mutations, many of them ever more virulent, and the selenium connection looks pretty compelling. (Trends in Microbiology, 2004, Vol. 12, pp. 417-423)
The conclusion of the researchers appears to be that taking a selenium supplement if one is low in the mineral, might well make a difference to one’s susceptibility to a virus, though of course, no one knows whether it would affect resistance to H5N1, or avian flu.
Selenium has many powerful effects, being a part of at least 25 proteins with antioxidant properties, and in its absence, causing both T-lymphocyte activity and antibody production ( important for immunity) to be adversely affected.
The lower your level of selenium, the higher your risk of osteoarthritis
Heading a research group from the University of Carolina, study leader Dr. Jordan determined that for every additional tenth of a part per million of selenium in volunteers’ bodies, there was a 15-20 per cent decrease in the risk of knee osteoarthritis.
“Our results suggest that we might be able to prevent or delay osteoarthritis of the knees and possibly other joints in some people if they are not getting enough selenium,” said Dr. Jordan.
The findings were presented in San Diego at the annual meeting of the American College of Rheumatology in 2005.
Studies show that selenium supplementation is tied to a dramatic reduction in the number of cancer cases and to the number of cancer mortalities. One such study was both significant enough and of a high enough quality to be published in the prestigious Journal of the American Medical Association.
The author of the study, Dr. Larry Clark, became interested in selenium because while doing a study of cancer mortality in North Carolina in the early 1980s, he noticed that there was a pattern of excess mortality from cancer that appeared to follow a geological map of the area. At first, he though this could be explained by pesticide use high in arsenic, or low carotenoid intake, and he was also looking at selenium intake, since selenium is an antagonist of arsenic.
He finally determined that selenium was directly correlated with the cancer data, and that in fact counties where selenium levels in the soil were low, there was a 10% higher mortality from cancer.
Building on Dr. Clark’s research, a recent (1999)study at the University of Colorado began following 1,312 patients with skin cancer. They were divided into 2 groups, one receiving organic selenium, the other a placebo. After 4 years, there was no discernible difference in the skin cancer rates, BUT when the researchers looked at other more life-threatening kinds of cancer, they found what Dr. Tim Byers, Professor of Preventive Medicine, called “the most exciting finding we’ve ever had in nutrition and cancer.” The selenium supplemented group had 63% fewer cancers of the prostate, 58% less cancer of the colon, and 46% less lung cancers than the placebo group. The Selenium used was a high selenium yeast called Selenomax.
A 2000 study using laboratory rats found selenium from broccoli was highly effective in protecting rats against potent injected carcinogens, with the protection increasing as the doses rose. You can access this study at www.ars.usda.gov.
In 2004, more studies in the Journal of the National Cancer Institute concluded: “The new epidemiologic data on selenium from Li et al. continue to support the initial impressions of this agent’s tremendous potential as a prostate cancer preventive agent. The emerging laboratory data greatly strengthen the biologic plausibility for this optimism and for the ongoing randomized clinical selenium trials, which ultimately will be necessary to define the potentially complex risk–benefit profile of this promising preventive agent . Meanwhile, science will continue peeling back layer after layer of the enormously deep and complex onion of selenium effects in the prostate.” http://jncicancerspectrum.oupjournals.org/cgi/content/full/jnci;96/9/645
What results can be brought about by optimizing one’s levels of selenium?
Dr. Clark’s 10 year study showed cancer mortality reduced by 50%, and overall mortality by 17%. Total cancer incidence was reduced by 37%, and three major kinds of cancer were especially affected: lung cancer was reduced by 46%, prostate cancer by 63%, and colon cancer by 38%. (JAMA 1996:276;1957-1963). Dr. Byers study confirms this result with even better odds!
Selenium and Colon Cancer
Evidence continues to mount that Selenium is intimately connected with rates of colon cancer. I have one link in Resources to a study suggesting that, and now an analysis of 3 studies comprising more than 1500 patients showed that those with the highest blood levels of selenium had the least risk of recurrence of colon cancer.
The researchers were clear: “higher selenium status may be related to decreased risk of colorectal cancer,” write the researchers in the Nov. 17 issue of the Journal of the National Cancer Institute. (J Natl Cancer Inst 2004;96:1645-1647,1669-1675.)
A particular “hero” of mine, Dr. Richard Passwater, goes into considerable detail about the variations of selenium content in the diet: he quotes one FDA survey which found NO selenium in five samples of a “balanced” diet in 1967. He himself reported in 1973 that he was unable to find any selenium in several TV dinners he analyzed. Refining, processing and cooking have an effect on selenium contents. It appears obvious that this is one incontrovertible case where only supplementation can assure one of proper levels of the mineral.
Consider also the fact that adequate levels of selenium are found only in a few states, and can be achieved through the diet only by eating locally grown foods…
It mush be remembered, though, that Selenium is after all considered a trace mineral, and high doses should be used with caution. In 2007, an eight year study concluded that taking more than 200 mcg of selenium daily could be connected to the development of blood sugar imbalances. The researchers commented that the risk of developing diabetes tended to be higher in people who had higher blood selenium levels at the start of the study.
How fortunate we are to be living in a time when this kind of research allows us to come up with inexpensive and effective ways to support our health : how fortunate, too, to be able to find the answers to the kind of question: why is this happening? Perhaps the day is not far away when we will know why many of the problems that plague us happen, and what we can do in detail to prevent them – perhaps we will even follow the ancient Chinese model of health care, when we pay our Health Professionals a stipend as long as they keep us healthy, and withhold payment when we become sick! It makes perfect sense to me!
Selenium and Esophageal Cancer
A Cornell study on Selenium and Cancer http://www.news.cornell.edu/releases/Jan97/selenium.ssl.html
A 2003 study on Viral Infections and Selenium Deficiency http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12730444&dopt=Abstract
Combine Selenium with Broccoli for twice the impact. http://www.guardian.co.uk/medicine/story/0,11381,927099,00.html
Colon Cancer & Selenium http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=837360
Related articles you may find interesting: Cancer