The role of vitamin E and daily requirements

There are 8 kinds of naturally occurring vitamin E, all of which are derivatives of benzohydropyran. According to their chemical structure, they can be divided into two groups: tocopherols and tocotrienols. Figure 12. Each type can be divided into four groups: α-, β-, γ-and δ-according to the number and position of methyl groups. Commercial vitamin E has the highest physiological activity of α-tocopherol. The physiological activities of β-and γ-tocopherols and α-trienol are only 40%, 8% and 20% of that of α-. Vitamin E is a light yellow oily substance with slight viscosity. It is stable under oxygen-free conditions and will not be destroyed even when heated above 200 ° C. However, vitamin E is easily oxidized and the color becomes darker in the air. Vitamin E is easy to oxidize, so it protects other easily oxidized substances such as vitamin A and unsaturated fatty acids from being destroyed. Vitamin E in food is mainly absorbed in the upper small intestine of animals, and is mainly carried by β-lipoprotein in the blood and transported to