Serum concentrations and cellular uptake of vitamin E

The high affinity receptor for low density lipoprotein (LDL) is demonstrated to function as a mechanism for delivery of vitamin E to cells. It is suggested that LDL which serves as its carrier is specific for d-alpha tocopherol which in turn is the most active biological form of vitamin E in human adults; also, its concentration is the highest in human adults serum as compared to other forms such as beta, gamma, delta, alpha tocopherol succinate and acetate when serum concentrations of human adults were measured after ingestion of various alpha tocopherol preparations the highest concentration in serum was achieved by d-alpha tocopherol over other forms as alpha tocopherol acetate or alpha tocopherol succinate. This data permits one to conclude that the most important biological form of vitamin E for absorption, transport and utilization is the d-alpha tocopherol. Specific receptor sites are apparent for d-alpha tocopherol in LDL, for which a high affinity receptor exists in the cells. This has been demonstrated to be a mechanism for cellular uptake of d-alpha tocopherol and cholesterol by cells.