Simultaneous analysis of retinol, beta-carotene and tocopherol levels in serum of Vietnamese populations with different incomes.

Abstract

In this study, we clarified the status of the fat-soluble vitamins retinol and tocopherol, as well as beta-carotene, as antioxidants in the prevention of cardiovascular disease in middle-aged Vietnamese populations with different incomes. In order to measure simultaneously the serum concentrations of retinol, beta-carotene and tocopherol, we carried out high-performance liquid chromatography analysis with three separate detectors. The analytical method was modified, omitting the saponification process, and used a multi-evaporating system with dry ice. This allowed the analysis to proceed more rapidly, use a small amount of serum (40 microL) and be free of hexane contamination to the environment. The analyses reflected an adequate status of vitamin A (serum retinol = 20 microg/dL), but inadequate status of beta-carotene and vitamin E (serum beta-carotene <40 microg/dL; serum tocopherol < 600 microg/dL) in all three Vietnamese populations. As large numbers of Vietnamese subjects were observed with very low serum concentrations of beta-carotene and tocopherol, higher consumptions of green and yellow vegetables, fruits, vegetable oils and other foods rich in vitamin E are recommended for these Vietnamese populations.