Effect of lycopene and tomato products on cholesterol metabolism.

BACKGROUND/AIMS Increased ingestion of tomato, containing lycopene, has been associated with a decreased risk for atherosclerosis, although the exact molecular mechanism is still unknown. Here we review the available evidence for a direct regulation of tomato lycopene on cholesterol metabolism using results from experimental and human studies. RESULTS In human macrophages lycopene dose dependently reduced intracellular total cholesterol. Such an effect was associated with a decrease in cholesterol synthesis through a reduction of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and expression, a modulation of low- density lipoprotein (LDL) receptor and acyl-coenzyme A:cholesterol acyltransferase activity. An increase in cholesterol efflux through an enhancement of ABCA1 and caveolin-1 expression was also observed. In animal models of atherosclerosis, lycopene and tomato products decreased plasma total cholesterol, LDL cholesterol and increased high-density lipoprotein cholesterol. In agreement with the experimental results, most human intervention trials analyzed show that dietary supplementation with lycopene and/or tomato products reduced plasma LDL cholesterol dependently on the dose and the time of administration. CONCLUSIONS Although lycopene and tomato products seem to possess direct hypocholesterolemic properties, more experimental studies are needed to better understand the mechanisms involved. There is also a need for more well-designed human dietary intervention studies to better clarify the role of lycopene as a hypocholesterolemic agent.