Table of Contents<\/b><\/p>\n [\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column][vc_single_image image=”7295″ img_size=”full”][vc_column_text single_style=””]Figure 1. Zinc: The Essential Element We Cannot Live Without<\/strong>. From cosmic origins to human health \u2013 why this trace metal shapes growth, immunity, and lifelong development. [Adapted and modified from: https:\/\/pubchem.ncbi.nlm.nih.gov\/periodic-table\/<\/a>] Pronounced \u201csel-ee-nee-um,\u201d<\/em> the element draws its name from Selene<\/strong>, the Greek goddess of the Moon. The lunar reference is fitting: selenium is both mysterious and essential, quietly influencing life, technology, and planetary chemistry.<\/p>\n Selenium\u2019s importance spans an astonishing range\u2014from sperm biology<\/strong> to semiconductor technology<\/strong>, from soil fertility<\/strong> to the manufacture of specialized glass<\/strong>. Its versatility reflects a unique chemical profile that allows selenium to participate in both biological and industrial systems with remarkable efficiency.<\/p>\n Selenium\u2019s biological significance was firmly established in 1975<\/strong>, when Yogesh Awasthi<\/strong> at Galveston, Texas, demonstrated that selenium is an integral component of glutathione peroxidase<\/strong>, a major antioxidant enzyme that neutralizes peroxides before they generate harmful free radicals<\/strong>. This discovery placed selenium at the center of the body\u2019s oxidative defense network. Today, it is known that every human cell contains more than one million atoms of selenium<\/strong>. The highest concentrations occur in hair, kidneys, and testicles<\/strong>, reflecting selenium\u2019s roles in detoxification, filtration, and reproduction. Yet selenium presents a familiar nutritional paradox: too little impairs health, but too much becomes toxic<\/strong>.<\/p>\n Nature synthesizes selenium in the form of methylselenocysteine<\/strong>, a selenium-containing amino acid found in Brassica vegetables, garlic<\/strong>, and other Allium species<\/strong>. Remarkably, the genetic code includes a specialized segment of messenger RNA<\/strong> that directs the incorporation of selenium into proteins. To date, approximately 14 selenoproteins<\/strong> have been identified. While they function in various tissues\u2014including the kidneys\u2014their most critical roles lie in sperm development<\/strong> and the early embryo<\/strong>, underscoring selenium\u2019s importance in fertility and early life [1-6] (see Table 1<\/strong>).[\/vc_column_text][\/vc_column][\/vc_row][vc_row el_id=”blog-scroll-point-3″][vc_column][vc_custom_heading text=”The Fine Line Between Necessity and Toxicity” use_theme_fonts=”yes”][vc_column_text single_style=””]Despite its essentiality, selenium can be profoundly hazardous in certain forms. Hydrogen selenide (H\u2082Se)<\/strong> is extremely toxic and nearly killed the chemist who first synthesized it.<\/p>\n Even dietary selenium can become dangerous when consumed in excess. A dose of 5 mg<\/strong> is highly toxic, and chronic low-level exposure\u2014historically, seen in certain industrial settings\u2014caused weight loss, anemia, dermatitis<\/strong>, and severe social isolation<\/strong> due to the unbearable odor emitted by affected individuals. The recommended maximum daily intake is 0.45 mg (450 \u03bcg)<\/strong>; exceeding this threshold risks selenium poisoning<\/strong>, most notably characterized by extremely foul breath and body odor<\/strong>. These odors arise from volatile methylated selenium compounds<\/strong> produced as the body attempts to eliminate the excess.<\/p>\n A dramatic example of selenium toxicity occurred in April 2009<\/strong> at the prestigious U.S. polo championships<\/strong>. Horses were given a mineral supplement called Biodyl<\/strong>, intended to provide selenium, magnesium, potassium, and B vitamins. Due to a compounding error, the batch contained excessive selenium<\/strong>, and within three hours<\/strong> of ingestion, the horses began to collapse. All 21 horses<\/strong> that received the supplement died from acute selenium poisoning\u2014a stark reminder of the razor-thin line between selenium\u2019s essentiality and its lethality.<\/p>\n [\/vc_column_text][\/vc_column][\/vc_row][vc_row el_id=”blog-scroll-point-4″][vc_column][vc_custom_heading text=”Selenium in Food and Human Health” use_theme_fonts=”yes”][vc_column_text single_style=””]<\/p>\n In the human diet, selenium appears primarily in two organic forms: selenocysteine<\/strong>, found in foods such as broccoli, garlic, and other Allium and Brassica vegetables, and selenomethionine<\/strong>, which predominates in meat<\/strong> and grain<\/strong> products. Structurally, selenocysteine contains one fewer carbon atom<\/strong> than selenomethionine, and unlike selenomethionine, it is not incorporated into proteins<\/strong> in place of methionine. This biochemical distinction influences how selenium is stored, metabolized, and mobilized within the body.<\/p>\n Daily selenium intake varies widely\u2014from 6 to 200 \u03bcg<\/strong>, depending on dietary patterns. The average Westerner consumes about 65 \u03bcg per day<\/strong>, an amount sufficient to prevent deficiency. This intake falls slightly below the recommended 75 \u03bcg\/day for men<\/strong>, but meets the recommended 60 \u03bcg\/day for women<\/strong>. Although selenium losses may occasionally exceed dietary absorption, this does not pose immediate risk because the body can draw upon selenium reserves stored in bone<\/strong>.<\/p>\n [\/vc_column_text][vc_column_text single_style=””]As a supplement, selenium is commonly taken as sodium selenite (Na\u2082SeO\u2083)<\/strong>, a water-soluble white crystalline compound, typically at a dose of 50 \u03bcg per day<\/strong>. Another natural option is brewer\u2019s yeast<\/strong> grown on selenium-enriched media, which accumulates selenium in organic forms.<\/p>\n For most individuals, selenium intake comes from breakfast cereals and bread<\/strong>, particularly whole-meal bread<\/strong>, where two slices can provide 30 \u03bcg<\/strong>. However, selenium content in wheat and meat varies significantly depending on the selenium levels in the soil<\/strong> where crops or livestock were raised. One of the richest natural sources is the edible mushroom Albatrellus pes-caprae<\/strong>, popular in Italy, which contains an extraordinary 3,700 \u03bcg per 100 g (fresh weight)<\/strong>. A single dish of this size would deliver eight times the recommended daily maximum<\/strong>. Fortunately, much of the selenium in mushrooms is poorly absorbed<\/strong>, making them safe to consume despite their high content.<\/p>\n [\/vc_column_text][\/vc_column][\/vc_row][vc_row el_id=”blog-scroll-point-5″][vc_column][vc_custom_heading text=”Where Deficiency, Disease, and Human Physiology Intersect” use_theme_fonts=”yes”][vc_column_text single_style=””]Selenium is indispensable for human health, and inadequate levels have been associated with cancer, heart disease, and infertility<\/strong>. Additional conditions linked to selenium deficiency include anemia, hypertension, arthritis, premature aging, muscular dystrophy, multiple sclerosis<\/strong>, and AIDS<\/strong>. Selenium strongly influences the activity of T-lymphocytes<\/strong>, the immune system\u2019s natural killer cells, which defend the body and can even destroy tumor cells.<\/p>\n The relationship between selenium and cancer prevention<\/strong> has been extensively studied. Epidemiological data suggest a protective effect, though findings are not universally consistent. In one U.S. trial involving 1,300 elderly participants<\/strong> over four years<\/strong>, selenium supplementation was associated with a 30% reduction<\/strong> in new cases of lung, bowel, and prostate cancer<\/strong>. While such results are compelling, other studies have not replicated these benefits, highlighting the complexity of selenium\u2019s role in carcinogenesis.<\/p>\n [\/vc_column_text][vc_column_text single_style=””]In certain diseases, however, the evidence for selenium deficiency is unequivocal. In regions of China such as Keshan<\/strong> and Linxian<\/strong>, where soils are severely depleted of selenium, children in the Keshan region<\/strong> suffered from a form of congestive heart failure<\/strong> known as Keshan disease<\/strong>. Residents of Linxian experienced unusually high rates of stomach cancer<\/strong>. In both cases, the incidence of disease declined markedly when selenium supplements<\/strong> were provided to the population [1-6].<\/p>\n Selenium also plays a critical role in male fertility<\/strong>. Some researchers attribute the declining sperm counts observed among European men to reduced dietary selenium intake. Over the past century, average selenium consumption in Europe has fallen by half<\/strong>, partly due to decreased consumption of selenium-rich foods such as kidney and liver<\/strong>, and partly because European wheat is grown in selenium-poor soils<\/strong>. A double-blind trial provided strong evidence for selenium\u2019s reproductive importance: men receiving selenium supplements doubled their output of viable sperm<\/strong>, while those given a placebo showed no improvement.<\/strong>[\/vc_column_text][\/vc_column][\/vc_row][vc_row el_class=”blog-text-35795″ el_id=”blog-scroll-point-6″][vc_column][vc_custom_heading text=”The Unexpected Defender Against Heavy Metals” el_class=”blog-text-35795″][vc_column_text single_style=””]Selenium is full of paradoxes. Although the element itself can be toxic even at relatively low doses<\/strong>, it possesses the remarkable ability to counteract the toxicity of other heavy metals<\/strong>\u2014most notably cadmium, mercury, arsenic, and thallium<\/strong>. Because of this, selenium is often described as a biological antagonist<\/strong> to these metals, capable of neutralizing or diminishing their harmful effects.<\/p>\n One of the most striking examples comes from tuna<\/strong>, a species known to accumulate higher-than-expected levels of mercury<\/strong>. Despite this, tuna remains generally safe to eat. The prevailing explanation is that the fish protects itself by absorbing one atom of selenium for every atom of mercury<\/strong> it takes in. This molecular pairing prevents mercury from exerting its full toxic potential.<\/p>\n [\/vc_column_text][vc_column_text single_style=””]The protective mechanism is elegantly chemical. Mercury binds strongly to selenium\u2014even more strongly than it binds to sulfur<\/strong>, the element it typically attaches to when poisoning enzymes. In mercury toxicity, the metal disrupts enzyme function by binding to sulfur-containing amino acids at critical catalytic sites. Selenium intervenes by pulling mercury away from these enzyme sites<\/strong>, forming stable mercury\u2013selenium complexes. Once mercury is removed, the previously blocked enzymes can resume normal function<\/strong>, restoring essential biochemical pathways.<\/p>\n This unexpected defensive role\u2014where a potentially toxic element becomes a guardian against even more dangerous toxins\u2014captures the essence of selenium\u2019s dual nature. It is an element capable of harm, yet indispensable for protection; a micronutrient that, in the right balance, shields life from some of the most potent poisons in the natural world. [\/vc_column_text][vc_column_text single_style=””](Cf. previous blog entitled as: \u201cZinc: The Essential Element We Cannot Live Without.<\/a>\u201d)<\/span>[\/vc_column_text][\/vc_column][\/vc_row][vc_row el_class=”blog-text-35795″ el_id=”conclusion”][vc_column][vc_custom_heading text=”Summary and Conclusions” el_class=”blog-text-35795″][vc_column_text single_style=””]Selenium stands out as a paradoxical yet indispensable trace element\u2014essential for antioxidant defense, thyroid hormone activation, immune function, fertility, and early embryonic development<\/strong>, yet capable of toxicity when intake exceeds a narrow safe range. Its biological influence is anchored in at least 14 selenoproteins<\/strong>, each contributing to cellular protection, metabolic balance, or reproductive success. The presence of over a million selenium atoms in every human cell<\/strong> underscores its deep evolutionary integration into human physiology.<\/p>\n Dietary selenium intake varies widely across the globe, shaped by soil composition, agricultural practices, and changing dietary patterns. This variability leaves certain populations vulnerable to deficiency-related disorders such as Keshan disease<\/strong>, impaired immunity, reduced sperm quality, and possibly increased risks of specific cancers. At the same time, selenium\u2019s ability to neutralize heavy metals<\/strong>\u2014including mercury, cadmium, arsenic, and thallium\u2014reveals a protective role that extends beyond nutrition into toxicology and environmental health.<\/p>\n [\/vc_column_text][vc_column_text single_style=””]Despite decades of research, important gaps remain. The full catalog of human selenoproteins<\/strong> is still incomplete, and current biomarkers of selenium status<\/strong> lack precision, making it difficult to distinguish between adequacy, marginal deficiency, and early toxicity. The relationship between selenium and cancer prevention<\/strong> remains inconsistent across studies, suggesting complex interactions with genetics, diet, and environmental exposures. Additionally, the long-term effects of mild chronic deficiency<\/strong> or low-grade excess<\/strong> are not well understood, particularly in vulnerable groups such as pregnant women, infants, and individuals with chronic illness.<\/p>\n Future research must focus on developing more accurate biomarkers<\/strong>, clarifying selenium\u2019s role in neurodevelopment and immune aging<\/strong>, and understanding how genetic variations in selenium metabolism<\/strong> influence individual requirements. There is also a growing need to refine personalized supplementation strategies<\/strong>, especially in regions with selenium-depleted soils or in populations with increased physiological demands. As we deepen our understanding, selenium continues to exemplify the delicate balance of essential elements\u2014one that sustains human health through mechanisms both expected and profoundly surprising. Folate (vitamin B9) is very important for your child\u2019s brain development!<\/p>\n During pregnancy, it helps prevent neural tube defects and plays a big role in forming a normal and healthy baby\u2019s brain and spinal cord. Folate also helps cells divide and assists in both DNA and RNA synthesis.<\/p>\n Emerging research suggests that the presence of FRAAs negatively impacts folate transport into the brain.<\/p>\n Yes, there is a test – The Folate Receptor Antibody Test (FRAT\u00ae<\/sup>) has emerged as a diagnostic tool for detecting the presence of FRAAs.<\/p>\n It is important to screen at an early age or as soon as possible as there may be corrective measures available. Please consult your physician for further information.<\/p>\n To request a test kit, click on the button below.<\/p>\n Request Now<\/a><\/p>\n<\/div>\n<\/div>\n [\/vc_column_text][vc_column_text single_style=”” el_class=”text-gray-23″]For information on autism monitoring, screening and testing please read our blog<\/a>.[\/vc_column_text][\/vc_column][\/vc_row][vc_row el_id=”blog-references” el_class=”blog-text-35795″][vc_column][vc_custom_heading text=”References” use_theme_fonts=”yes”][vc_column_text single_style=”” el_id=”blog-ref-3564″]<\/p>\n\n
\n[\/vc_column_text][\/vc_column][\/vc_row][vc_row el_id=”blog-scroll-point-1″][vc_column][vc_custom_heading text=”Introduction”][vc_custom_heading text=”Selenium \u2014 The Moon\u2019s Element That Guards Human Life”][vc_column_text single_style=”” el_id=”blog-scroll-point-1″]Selenium carries a name born from the heavens\u2014drawn from Selene<\/strong>, the Greek goddess of the Moon\u2014yet its influence is felt in every corner of human biology. It is an element of paradoxes: essential yet potentially toxic<\/strong>, rare in the Earth\u2019s crust yet present in every cell of the human body<\/strong>, subtle in its daily actions yet capable of shaping health, development, and survival in profound ways.
\n[\/vc_column_text][vc_column_text single_style=””]Its scientific story began to unfold only in the late 20th century. In 1975<\/strong>, researchers discovered that selenium is a critical component of glutathione peroxidase<\/strong>, the enzyme that shields cells from destructive peroxides before they can ignite cascades of free-radical damage<\/strong>. A decade later, selenium emerged again at the center of human physiology when it was found in deiodinase<\/strong>, the enzyme that activates thyroid hormones and governs metabolic rhythm. These discoveries transformed selenium from a chemical curiosity into a cornerstone of antioxidant defense, endocrine balance, and cellular protection<\/strong>.
\n[\/vc_column_text][vc_column_text single_style=””]But selenium\u2019s reach extends even further. Nature has woven it into at least 14 selenoproteins<\/strong>, many of which are indispensable for sperm formation, embryonic development,<\/strong> and immune resilience<\/strong>. Its presence in foods\u2014whether as selenocysteine in garlic and broccoli or selenomethionine in grains and meat\u2014reflects the delicate interplay between soil, agriculture, and human nutrition. Too little selenium invites vulnerability: weakened immunity, heart dysfunction, impaired fertility, and region-specific diseases such as Keshan disease<\/strong>. Too much, however, tips the balance toward toxicity, with unmistakable signs like foul breath, dermatitis<\/strong>, and systemic poisoning [1-6].
\n[\/vc_column_text][vc_column_text single_style=””]And then comes selenium\u2019s most surprising role: its ability to neutralize some of the world\u2019s most dangerous heavy metals<\/strong>. Mercury, cadmium, arsenic, and thallium\u2014elements that devastate enzymes and tissues\u2014are disarmed by selenium\u2019s stronger chemical pull. Even mercury-rich tuna remains safe to eat because the fish binds one selenium atom for every mercury atom<\/strong>, forming protective complexes that prevent biochemical harm.[\/vc_column_text][vc_column_text single_style=””]Selenium is, in every sense, an element of contrasts\u2014a guardian and a threat, a nutrient and a toxin, a trace mineral with outsized influence<\/strong>. Its story reminds us that life depends not only on abundance, but on balance; not only on the elements we see, but on those that work quietly in the background, shaping health in ways both subtle and extraordinary.[\/vc_column_text][\/vc_column][\/vc_row][vc_row el_id=”blog-scroll-point-2″][vc_column][vc_custom_heading text=”Selenium: The Moon-Named Element That Shapes Life” use_theme_fonts=”yes”][vc_column_text single_style=””]<\/p>\nOrigins and Etymology<\/h3>\n
Life\u2019s Quiet Guardian in Every Cell<\/h3>\n
Element of Life<\/h3>\n
\n[\/vc_column_text][vc_single_image image=”7296″ img_size=”full”][vc_column_text single_style=””]Table 1. Element of Life ~ Selenium in the Human Body.<\/strong>
\n[\/vc_column_text][vc_column_text single_style=””]Further insight came in 1991<\/strong>, when Professor Dietrich Behne<\/strong> at the Hahn-Meitner Institute in Berlin identified selenium within deiodinase<\/strong>, the enzyme responsible for activating thyroid hormones. This finding linked selenium directly to thyroid function<\/strong>, metabolism, and energy regulation.<\/p>\nFrom Earth to Plate: How Diet Shapes Selenium Status<\/h3>\n
\n[\/vc_column_text][vc_column_text single_style=””]Some foods are exceptionally rich in selenium. Brazil nuts<\/strong> and molasses (black treacle)<\/strong> contain >100 \u03bcg per 100 g<\/strong>, while seafoods such as tuna, cod, and salmon<\/strong>, and organ meats like liver and kidney<\/strong>, exceed 30 \u03bcg per 100 g<\/strong>. Many nuts\u2014including peanuts and cashews<\/strong>\u2014contain similar amounts; a 100-gram bag of cashews<\/strong> may provide 65 \u03bcg<\/strong>. Additional selenium-dense foods include wheat germ, bran<\/strong>, and brewer\u2019s yeast<\/strong> [1-6].<\/p>\n
\n[\/vc_column_text][\/vc_column][\/vc_row][vc_row el_class=”blog-text-35795″ el_id=”blog-scroll-point-12″][vc_column][vc_custom_heading text=”Take-Home Messages” el_class=”blog-text-35795″][vc_column_text single_style=””]<\/p>\n\n
\n[\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text single_style=”” el_class=”blog-banner-section”]<\/p>\nDid You Know? Folate Receptor Autoantibodies (FRAAs) may impede proper folate transport.<\/h4>\n
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Is there a test for identifying Folate Receptor Autoantibodies (FRAAs)?<\/h4>\n
![\"FRAT](\"https:\/\/autism.fratnow.com\/blog\/wp-content\/uploads\/2023\/12\/frat-mascot-image.webp\")
<\/div>\n<\/div>\n\n
\nhttps:\/\/pubmed.ncbi.nlm.nih.gov\/22381456\/<\/a>
\n(A landmark review covering selenium biology, deficiency, toxicity, selenoproteins, and global health implications.)<\/em><\/strong><\/li>\n
\nhttps:\/\/pubmed.ncbi.nlm.nih.gov\/27095226\/<\/a>
\n(Defines the roles of major selenoproteins, including glutathione peroxidases and thioredoxin reductases.)<\/em><\/strong><\/li>\n
\nhttps:\/\/pubmed.ncbi.nlm.nih.gov\/20812787\/<\/a>
\n(A comprehensive synthesis of selenium metabolism, biomarkers, dietary sources, and clinical outcomes.)<\/em><\/strong><\/li>\n
\nhttps:\/\/pubmed.ncbi.nlm.nih.gov\/29974401\/<\/a>