Selenium (Elemental Se) vs. Vitamin E (d-Alpha-Tocopherol)
Comparing 2 standards across 9 specifications. 9 key differences identified.
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.
Vitamin E is the principal fat-soluble peroxyl radical-scavenging antioxidant protecting cellular polyunsaturated membrane phospholipids. Adult RDA is 15 mg (22.4 IU) of d-alpha-tocopherol, with a Tolerable Upper Limit of 1,000 mg (1,500 IU)/day.
Specification Comparison Table
9 Parameters| Parameter / Spec | ||
|---|---|---|
|
Nutrient Type
|
Essential Trace Element | Fat-Soluble Chromanol Lipophilic Vitamin |
|
Adult RDA / RDI
|
55 µg / day (60 µg pregnancy, 70 µg lactation) | 15 mg / day (22.4 IU) of 2R-alpha-tocopherol |
|
Tolerable Upper Limit (UL)
|
400 µg / day (Avoid selenosis / garlic breath, hair/nail brittleness) | 1,000 mg / day (1,500 IU synthetic) (Excess impairs Vitamin K clotting cascade) |
|
Chemical Forms
|
Selenomethionine (Plant organic), Selenocysteine (Animal selenoprotein), Sodium Selenite / Selenate (Inorganic) | RRR-alpha-Tocopherol (Natural d-alpha), all-rac-alpha-Tocopherol (Synthetic dl-alpha), Gamma/Delta-Tocopherols |
|
Primary Biological Function
|
Glutathione Peroxidase (GPx1-4) lipid hydroperoxide neutralization, Iodothyronine Deiodinases (Converts thyroid T4 into active T3), Thioredoxin Reductase (TXNRD) | Breaks lipid peroxidation chain in PUFA cell membranes, protects LDL from oxidative modification, maintains erythrocyte membrane integrity |
|
Deficiency Condition
|
Keshan Disease (Endemic juvenile cardiomyopathy), Kashin-Beck Disease (Deforming osteoarthropathy), Impaired thyroid metabolism | Hemolytic anemia, Spinocerebellar ataxia, Peripheral neuropathy, Loss of vibratory/proprioceptive sense |
|
Top Whole Food Sources
|
Brazil Nuts (1 single nut provides ~70–90µg / 130–160% RDA), Eastern Oysters, Yellowfin Tuna, Halibut, Sardines, Beef Liver, Eggs | Wheat Germ Oil, Sunflower Seeds, Raw Almonds, Hazelnuts, Sunflower Oil, Spinach, Hass Avocado |
|
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 | — |
|
Hepatic Alpha-TTP Specificity
|
— | The liver secretes only alpha-tocopherol into VLDL via Alpha-Tocopherol Transfer Protein (alpha-TTP); other tocopherols are degraded in bile |