Grapefruit juice and serum lipids in healthy adults

Abstract

Background: Grapefruit juice has been reported to decrease serum cholesterol in patients with hyperlipidaemia. Whether grapefruit juice can influence serum lipids in healthy people had not been investigated. Objective: To investigate the effect of grapefruit juice on serum lipid levels in healthy adults by comparing grapefruit juice with apple juice in the same individuals. Design: In a cross-over study, 28 healthy volunteers took 250 ml grapefruit juice or apple juice daily for 3 weeks followed by a 3 week washout, and then the juices were swapped for the second intervention period. Serum samples for total, low-density lipoprotein (LDL)-, high-density lipoprotein (HDL)-cholesterol and triglycerides were collected before and after each period, and analysed batchwise after the study. Results: In the grapefruit juice period LDL-cholesterol decreased by 6% (p=0.04). Serum lipids were not significantly affected by apple juice. There were no differences in lipid levels between grapefruit juice and apple juice periods. During the whole 9 week study total and LDL-cholesterol decreased by 8% (p<0.0001) and 14% (p<0.0001), respectively, whereas HDL-cholesterol increased by 6% (p=0.028). Conclusions: Consumption of grapefruit juice decreased LDL-cholesterol by 6%, but with no significant differences compared with the apple juice or washout periods. Thus, the hypocholesterolaemic effect of grapefruit juice cannot be separated from the general time effect encountered in this study. Keywords: apple juice; cholesterol; cross-over; grapefruit juice; HDL; LDL; triglycerides