From the Guidelines
Vitamin E alpha tocopherol and gamma tocopherol are two distinct forms of vitamin E with different properties and functions, and while alpha tocopherol is the primary form found in supplements and has strong antioxidant properties, gamma tocopherol has unique benefits including better ability to neutralize nitrogen-based free radicals and potentially stronger anti-inflammatory effects. The key difference between the two forms lies in their biological activity, with alpha tocopherol being the most biologically active form and the primary form used to establish vitamin E requirements 1.
Key Differences
- Alpha tocopherol is the most abundant form of vitamin E in the diet and plasma, and it has been shown to be the most biologically active form 1
- Gamma tocopherol has unique benefits including better ability to neutralize nitrogen-based free radicals and potentially stronger anti-inflammatory effects
- Alpha tocopherol is preferentially retained in the body through a specific transport protein, and it has strong antioxidant properties that protect cell membranes from oxidative damage 1
- The body metabolizes these forms differently, with alpha tocopherol having higher bioavailability
Health Benefits
- Consuming a variety of vitamin E-rich foods that provide both alpha and gamma tocopherol is ideal for optimal health benefits, rather than relying solely on alpha tocopherol supplements
- Food sources like nuts and seeds typically contain both forms, with some foods like walnuts and sesame seeds being particularly rich in gamma tocopherol
- Vitamin E, particularly alpha tocopherol, plays an essential role in normal metabolism, protecting membrane lipids, lipoproteins, and depot fats from lipid peroxidation, and regulating the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) 1
Recommendations
- The recommended daily intake of vitamin E is 15 mg for adults, with alpha tocopherol being the form used to establish vitamin E requirements 1
- For optimal health benefits, it is recommended to consume a variety of vitamin E-rich foods that provide both alpha and gamma tocopherol, rather than relying solely on alpha tocopherol supplements.
From the Research
Differences between Vitamin E Alpha Tocopherol and Gamma Tocopherol
- Vitamin E consists of a group of eight isomers, including four tocopherols (alpha-, beta-, gamma-, delta-tocopherol) and four tocotrienols (alpha-, beta-, gamma-, delta-tocotrienol) 2.
- Alpha-tocopherol and gamma-tocopherol are two forms of vitamin E that have different properties and effects on human health.
- Gamma-tocopherol is the major form of vitamin E in many plant seeds and in the US diet, but has drawn little attention compared with alpha-tocopherol, the predominant form of vitamin E in tissues and the primary form in supplements 3.
- Gamma-tocopherol appears to be a more effective trap for lipophilic electrophiles than is alpha-tocopherol, and it possesses unique features that distinguish it from alpha-tocopherol, including anti-inflammatory properties 3.
Antioxidant and Anti-Inflammatory Effects
- Both alpha-tocopherol and gamma-tocopherol have antioxidant properties, but gamma-tocopherol has been shown to have superior antioxidant and anti-inflammatory effects compared to alpha-tocopherol 4.
- Gamma-tocopherol can trap reactive nitrogen species by forming 5-nitro-γT, and appears to show superior protection of mitochondrial function 4.
- Gamma-tocopherol inhibits ionophore-stimulated leukotrienes by blocking 5-lipoxygenase (5-LOX) translocation in leukocytes, decreases cyclooxygenase-2 (COX-2)-catalyzed prostaglandins in macrophages and blocks the growth of cancer cells but not healthy cells 4.
Metabolism and Bioavailability
- Gamma-tocopherol is well absorbed and accumulates to a significant degree in some human tissues, but it is metabolized largely to 2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxychroman (gamma-CEHC), which is mainly excreted in the urine 3.
- Gamma-CEHC has natriuretic activity and may be of physiologic importance 3.
- Supplementation with gamma-tocopherol increases both gamma-tocopherol and alpha-tocopherol levels, whereas high doses of alpha-tocopherol deplete plasma and tissue gamma-tocopherol 3.
Disease Management
- Some human and animal studies indicate that plasma concentrations of gamma-tocopherol are inversely associated with the incidence of cardiovascular disease and prostate cancer 5, 3.
- Supplementation of gamma-tocopherol has been shown to mitigate inflammation and disease symptoms in animal models with induced inflammation, asthma, and cancer, and to decrease inflammation markers in patients with kidney diseases and mild asthma 4.