From the Research
Beta-tocopherol (vitamin E) deficiency is typically defined as a serum level below 5 mg/L (or 5 μg/mL). This threshold represents the point at which inadequate vitamin E status may lead to clinical manifestations, such as neurological symptoms including peripheral neuropathy, ataxia, and impaired immune function due to its important role as an antioxidant that protects cell membranes from oxidative damage 1. For adults, the recommended dietary allowance (RDA) for vitamin E is 15 mg daily of alpha-tocopherol, the most active form. If deficiency is detected, supplementation with 400-800 IU of vitamin E daily is typically recommended until normal levels are restored. Certain populations are at higher risk for deficiency, including those with fat malabsorption disorders, as vitamin E is a fat-soluble vitamin requiring proper fat absorption for utilization. Regular monitoring of levels during supplementation is important to ensure restoration of adequate status without reaching excessive levels.
Some key points to consider:
- Vitamin E has eight naturally occurring isoforms, namely α-, β-, γ- and δ-tocopherol and α-, β-, γ- and δ-tocotrienol 1
- α-Tocopherol is regarded the dominant form in vitamin E as the α-tocopherol transfer protein in the liver binds mainly α-tocopherol, thus preventing its degradation 1
- Tocotrienols have been shown to possess superior antioxidant and anti-inflammatory properties over α-tocopherol 1
- Vitamin E therapy has been investigated in various conditions, including chronic kidney disease, showing promising results in the secondary prevention of cardiovascular disease, as well as of immune and hematological complications 2
It's worth noting that the most recent and highest quality study 1 provides an update on vitamin E therapeutic potentials, protective effects and modes of action beyond cancer, with comparison of tocopherols against tocotrienols. However, the definition of beta-tocopherol deficiency remains consistent with previous studies, with a serum level below 5 mg/L (or 5 μg/mL) being the threshold for clinical manifestations.