A lutein enriched diet modified lipoprotein subfractions and prevented cholesterol accumulation in aortas in guinea pigs

Abstract

Two groups of guinea pigs were fed a control diet (n =9) or a diet containing 0.1% lutein (n =10) for 12 wk to evaluate the effects of this carotenoid on lipoprotein metabolism and potential protection against atherosclerosis. Lipoprotein subfracion and size were measured using nuclear magnetic resonance, hepatic and aortic lipids were extracted with chloroform:methanol to measure tissue cholesterol. Lutein concentrations in liver were determined by HPLC. Plasma total and LDL cholesterol were not different between groups, however, the lutein treated group had higher concentrations of plasma total VLDL and LDL particles (P < 0.05) and lower concentrations of large HDL particles (P < 0.01) and higher concentrations of medium and small HDL compared to the control group. The increases in these particles may be related to the way lutein is transported in plasma, mainly in LDL and small HDL. In contrast, aortic cholesterol was lower in the lutein (3.7 ± 1.0 mg/g) compared to the control group (6.0 ± 0.9 mg/g). Guinea pigs from the lutein group had an average of 23.83 ± 5.61nmol/g of lutein while this carotenoid was not detected in the control group. Hepatic lutein concentrations were negatively correlated with small LDL (r = −0.561, P < 0.05) and with aortic cholesterol (r=−.734, p< 0.01). These results suggest that lutein in the liver is related to less formation of small LDL particles and therefore lower deposition of cholesterol in the aorta.