Interdependence of serum concentrations of vitamin K1, vitamin E, lipids, apolipoprotein A1, and apolipoprotein B:: importance in assessing vitamin status

Vitamin E (alpha-tocopherol) and vitamin K-1 (phylloquinone) are fat-soluble vitamins and are important nutrients in health and disease. In this study serum concentrations of vitamin E and vitamin K-1, lipids and apolipoproteins A(1) and B were measured in neonates, normal and hyperlipidaemic individuals in an attempt to establish their interrelationships. A high degree of correlation was observed between the concentrations of the vitamins and those of lipids and apolipoproteins (r ranged from 0.42 to 0.92; p < 0.001). Stepwise linear regression methods determined that serum concentrations of both vitamin E and vitamin K-1 could best be predicted by using equations excluding lipids but containing only apolipoprotein A(1) and B concentrations. Correlation coefficients between predicted and measured values were 0.89 for serum vitamin E, and 0.83 for serum vitamin K-1 concentrations. To test the validity of the derived formulae, measured and estimated vitamin K-1 and vitamin E concentrations in serum were determined in another group of neonates, normal adults and hypercholesterolemic adults and the comparisons were shown to be very good. These results indicate that the serum levels of both vitamins depend critically on the concentration of the Lipoprotein carriers, apolipoproteins A(1) and B. Hence, in order to identify variations in serum vitamin K-1 and vitamin E concentrations, which are independent of variations in carrier concentration, it will be necessary to express these serum vitamins as ratios of vitamins to apolipoprotein A(1) and B carriers. (C) 1999 Elsevier Science B.V. All rights reserved.