The Importance of Selenium
The Importance of Selenium
Selenium is a trace mineral considered to be “essential”, meaning that it must be obtained through the diet. While, as a trace mineral, it is only required in small amounts (micrograms), it nonetheless plays a major role in human health, being required for metabolic and thyroid functions, reproduction, and DNA production.
Let’s have a look at the scientifically-proven health benefits of selenium, and then examine its potential as an antiviral agent.
Benefits of Selenium
Cancer Serving as an antioxidant, in part by boosting glutathione levels, selenium reduces oxidative stress by preventing free radical damage to DNA. Since free radical damage is linked to causing cancer it is no surprise selenium has been shown to lower the risk of certain cancers.
An overview of 69 studies (including over 350,000 people) found high blood levels of selenium to be associated with lower risk of a variety of cancers, including breast, colon, lung, and prostate cancer.
Heart Disease Low selenium levels have been linked to an increased risk of heart disease. An analysis of 25 studies, showed a 50% increase in blood selenium levels to be associated with a 24% reduction in heart disease risk.
Selenium also lowers levels of C-reactive protein (a marker of inflammation), one of the main risk factors for heart disease.
Alzheimer’s Disease Some studies have shown that patients with Alzheimer’s disease have lower blood levels of selenium, while other studies have confirmed that increased antioxidant intake (from food and supplements) can help to improve the memory in those with Alzheimer’s.
One, albeit small, study found that one Brazil nut per day (high in selenium) improved mental functions in patients with mild cognitive impairment.
Thyroid Function Selenium is necessary for the proper functioning of your thyroid gland, playing a critical role in the production of thyroid hormones. This is not surprising since thyroid tissue contains more selenium than any other organs in the body.
A study (covering over 6,000 people) found low serum levels of selenium to be associated with increased risk of autoimmune thyroiditis, and hypothyroidism.
Asthma Research has found people with asthma have lower blood levels of selenium, and that supplementing with selenium can help to reduce asthma symptoms.
One study showed those asthmatic patients with higher levels of selenium had better lung function than those with lower levels, and another found that supplementing with 200 mcg of selenium per day reduced use of corticosteroid medications.
Immunity Our immune system identifies and fights off potential threats, including bacteria, parasites, and viruses. Selenium is required for a healthy immune system, where, as an antioxidant, it helps to lower oxidative stress, thereby reducing inflammation, and enhancing immunity.
Studies have shown that higher blood levels of selenium are associated with improved immune function, while selenium deficiency reduces immune function, and slows immune response.
Selenium’s Antiviral Properties More than just generally supporting the immune system, there is strong evidence that selenium can specifically strengthen the immune response in people with viral conditions, including hepatitis C, HIV, influenza, poliovirus, and West Nile virus.
The clinical review of selenium that summarizes these antiviral benefits also includes its value in treating bacterial infections, including tuberculosis (and Helicobacter pylori). This is worth mentioning here, since as discussed in the last newsletter, those who die from influenza-type viruses usually die from the ensuing bacterial infection of the respiratory tract.
Here is some direct material from that clinical review:
“The habitual diet is often not sufficient to meet the increased demands for micronutrients in infectious diseases. Dietary multimicronutrient supplements containing selenium up to 200 mcg have potential as safe, inexpensive, and widely available adjuvant therapy in viral infections (e.g., HIV, Influenza A Virus) as well as in coinfections by HIV and M. tuberculosis to support the chemotherapy and/or to improve fitness and quality of life of the patients. Because many of these patients experience broad nutritional deficiencies, multimicronutrient supplementation appears to be a more promising approach than the use of selenium alone. Dietary supplementation with selenium-containing multimicronutrients might also be useful to improve supportive care and to strengthen the immune system of patients suffering from newly emerging viral diseases, such as in the current epidemic of Ebola fever in West Africa.” (Study)
Supplementing with Selenium The RDA of selenium for teens and adults is 55 mcg, 60 mcg for pregnant women, and 70mcg for those breastfeeding. However, most natural health practitioners, and many of the clinical studies referred to above, suggest that we should obtain from 100 to 200 mcg of selenium, daily.
Food can provide some selenium, though the only appreciable amount is found in brazil nuts. And, as with all foods and minerals, the selenium content of crops, including brazil nuts, depends on the soil they are grown in.
“For example, one study showed that the selenium concentration in Brazil nuts varied widely by region. While a single Brazil nut from one region provided up to 288% of the recommended intake, others provided only 11%.” (Source)
This wide variance implies that one should not overdo consuming Brazil nuts, since it could be possible to ingest far too much selenium, if the nuts happen to be extremely high in that mineral. Selenium, like all trace minerals, in excess becomes a heavy metal, at which point it can be toxic, and even fatal. Though selenium toxicity is rare, outside of industrial settings, one should not exceed 400 mcg per day. (And, as always, I suggest selenium be taken only 5 days a week. Then, in the event of ingesting more than the body requires, the two days off will give the body a chance to use up the excess. Consider it a safety valve.)
The Best Form of Selenium There are a variety of forms of selenium to be found in supplements. The selenium salts (sodium selenite and sodium selenate), found in cheap multivitamins, have both been shown to be “less bioavailable than organically bound forms of selenium (Am J Clin Nut,1982). Organically bound forms of selenium are high selenium yeast or selenomethionine. High selenium yeast contains three organic selenium compounds (selenomethionine, selenocysteine and methylselenocysteine), whereas selenomethionine is a single amino acid (methionine) with a selenium molecule attached to it. The most recent study shows that 100% organically bound selenium yeast is most effective for reducing oxidative stress as compared to selenomethionine.”
The most commonly used forms of selenium found in high quality supplements are yeast-derived selenium, and selenomethionine, with selenomethionine now being more commonly used. My research has convinced me that the selenium derived from yeast is superior, and more effective than selenomethionine (as the above study confirms).
In an article, published in the Journal of the American Medical Association (1996), Dr. Larry C. Clark, and his colleagues, found a reduction in cancer in individuals receiving a daily 200 mcg yeast-derived selenium supplement (“SelenoExcell”). Patients who took daily doses of this selenium had 63% fewer cases of prostate cancer, 58% fewer cases of colon or rectal cancers, and 45% fewer lung cancers than those not receiving the supplement. More recent research (2015) by John Richie Jr, PhD, at Penn State, found yeast-derived selenium (SelenoExcell) significantly reduced oxidative stress biomarkers far more than selenium methionine.
Finally, one more reference: “This difference in effectiveness of SY (selenium from yeast) vs. SeMet (selenomethionine) in protecting against oxidative stress may, in part, help explain the results of previous trials which demonstrated the effectiveness of SY, but not SeMet, at reducing the risk for Prostate Cancer. In fact SY was the only form associated with a pattern of decreased DNA damage in rodents.” (Study)
I have spent a lot of time on the distinction between these two forms of selenium because if we are going to get the broadest benefits from using a selenium supplement, we want to choose the most effective product. I (along with Dr. Mercola) believe that yeast-derived selenium, especially in the trademarked, clinically-proven version, SelenoExcell, is the preferred version to supplement with.
Now, let’s refer back to a comment from the clinical study discussed in the section on “Selenium’s Antiviral Properties”: “Because many of these patients experience broad nutritional deficiencies, multimicronutrient supplementation appears to be a more promising approach than the use of selenium alone.”
Of course this makes sense given that all nutrients require cofactors. Thus one can get their selenium in a multivitamin product (such as NutriPods), or in a multi-mineral product (such as Mineral Mix). And, of course given my preference for SelenoExcell, and the fact that I formulate for NutriStart, both our NutriPods and Mineral Mix use SelenoExcell for the selenium component.