Lyophilized carrot ingestion lowers lipemia and beneficially affects cholesterol metabolism in cholesterol-fed C57BL/6J mice.

Abstract

Several lines of evidence indicate that diet rich in fruit and vegetable can protect against cardiovascular diseases by acting on cholesterol metabolism and on oxidative stress. The aim of this study was to assess whether daily carrot consumption (provided as lyophilized powder) could differentially influence the consequences of cholesterol supplementation on lipid metabolism and oxidative stress in C57BL/6J mice. Fourteen mice were randomized in four groups. Mice were fed either control diets (without or with 0.25% cholesterol added) or lyophilized carrot enriched diets (20% wt/wt without or with 0.25 % cholesterol added) for 4 weeks. Cholesterol and triglycerides in plasma and in liver were measured at the end of the experimental period. Fecal excretion of sterols was evaluated. Vitamin E and carotenoid concentrations were also determined. Several biomarkers relative to oxidative stress such as FRAP (Ferric Reducing Ability of Plasma) and isoprostanes were investigated. Feeding the carrot diet resulted in a decrease of cholesterol (-41%) and triglycerides (-49 %) in plasma and in the liver (-41% and -39%, respectively) in animals fed cholesterol-supplemented diets. Carrot diet induced an increase of total neutral sterols fecal excretion, which inhibits digestive cholesterol absorption. Carrot diet increased antioxidant status in cholesterol-fed mice as related by the 16% higher FRAP values. Although vitamin E was not affected by carrot diet, vitamin E/TG ratio was significantly higher in animals fed carrot diets. The carrot diet induced an increase of vitamin E in the heart in both cholesterol-free and cholesterol-supplemented mice suggesting a higher protection of this tissue. This study shows that carrot ingestion decreases lipemia and improves antioxidant status in mice. Such results suggest that carrot intake may exert a protective impact against CVD linked to atherosclerosis. It is likely that these effects could be due to the synergistic effect of fiber and associated antioxidants.