tocoferoles

Tocoferoles, or tocopherols, are a family of fat-soluble compounds that constitute vitamin E in humans. The class includes four main tocopherols—alpha-, beta-, gamma-, and delta-tocopherol—which differ in methylation of the chromanol ring. Together with tocotrienols, they form the vitamin E family, which is involved in protecting lipids from oxidative damage and supporting cellular health.

The primary role of tocopherols is as lipid-soluble antioxidants. They scavenge lipid peroxyl radicals and interrupt chain reactions that degrade polyunsaturated fatty acids in membranes and lipoproteins. In addition to antioxidant activity, tocopherols may influence cell signaling and immune function, though these effects are less well defined.

Dietary sources and metabolism: Rich sources include vegetable oils (such as sunflower, safflower, olive, and canola), nuts, seeds, and green leafy vegetables. Because tocopherols are fat-soluble, absorption increases with dietary fat; they are incorporated into chylomicrons and reach the liver, where alpha-tocopherol transfer protein preferentially selects alpha-tocopherol for circulation. Deficiency is rare but can occur with fat malabsorption or certain diseases and leads to neurological symptoms, anemia, and immune impairment.

Forms and supplements: Natural alpha-tocopherol occurs as RRR-alpha-tocopherol; synthetic vitamin E (all-rac-alpha-tocopherol) contains eight stereoisomers with generally lower biological activity. The evidence for high-dose supplementation in disease prevention is mixed, and many guidelines prioritize obtaining vitamin E from diet rather than supplements except in deficiency or specific clinical contexts.