Magnesium (Elemental Mg) vs. Selenium (Elemental Se)
Comparing 2 standards across 9 specifications. 9 key differences identified.
Magnesium is an essential macromineral required as an enzymatic cofactor in over 300 biochemical reactions including ATP synthesis, DNA replication, and neuromuscular transmission. Adult RDA is 400–420mg (men) / 310–320mg (women).
Selenium is an essential trace element incorporated as Selenocysteine (the 21st amino acid) into 25 human selenoproteins including Glutathione Peroxidases (GPx) and Iodothyronine Deiodinases (T4->T3 conversion). Adult RDA is 55 µg, with a Tolerable Upper Limit of 400 µg/day.
Specification Comparison Table
9 Parameters| Parameter / Spec | ||
|---|---|---|
|
Nutrient Type
|
Essential Macromineral | Essential Trace Element |
|
Adult RDA / RDI
|
400 – 420 mg / day (Men) / 310 – 320 mg / day (Women) | 55 µg / day (60 µg pregnancy, 70 µg lactation) |
|
Tolerable Upper Limit (UL)
|
350 mg / day (From supplemental forms only; no limit on whole foods) | 400 µg / day (Avoid selenosis / garlic breath, hair/nail brittleness) |
|
Chemical Forms
|
Magnesium Glycinate (Chelate), Citrate, Malate, Oxide, L-Threonate | Selenomethionine (Plant organic), Selenocysteine (Animal selenoprotein), Sodium Selenite / Selenate (Inorganic) |
|
Primary Biological Function
|
Mg-ATP complex cofactor (>300 enzymes), NMDA receptor gatekeeper, Protein synthesis, Muscle relaxation | Glutathione Peroxidase (GPx1-4) lipid hydroperoxide neutralization, Iodothyronine Deiodinases (Converts thyroid T4 into active T3), Thioredoxin Reductase (TXNRD) |
|
Deficiency Condition
|
Muscle cramps, Tremors, Ventricular arrhythmias, Insulin resistance, Insomnia | Keshan Disease (Endemic juvenile cardiomyopathy), Kashin-Beck Disease (Deforming osteoarthropathy), Impaired thyroid metabolism |
|
Top Whole Food Sources
|
Pumpkin Seeds, Hemp Hearts, Chia Seeds, Almonds, Spinach, Black Beans, Dark Chocolate | Brazil Nuts (1 single nut provides ~70–90µg / 130–160% RDA), Eastern Oysters, Yellowfin Tuna, Halibut, Sardines, Beef Liver, Eggs |
|
Cellular Distribution
|
99% intracellular (60% bone, 39% skeletal muscle, <1% serum) | — |
|
Soil Selenium Geographical Variability
|
— | Plant selenium reflects regional soil content; volcanic soils (South America, Great Plains) are rich, while parts of China, Scandinavia, and New Zealand are depleted |