Lipoprotein carotenoid profiles and the susceptibility of low density lipoprotein to oxidative modification in healthy elderly volunteers

Objectives:
To determine antioxidant levels in plasma, low density lipoprotein (LDL) and high density Lipoprotein (HDL) before and after supplementation with a carotene mixture or lycopene; to examine the interrelationships between carotenoids and tocopherols in plasma, LDL and HDL under normal dietary conditions and after supplementation with carotene or lycopene; and to investigate whether supplementation with a carotene mixture or lycopene could enhance the ability of LDL to withstand oxidative stress in vitro, in a group of healthy elderly people aged greater than or equal to 65 y.

Design:
Randomized placebo controlled double blind study.

Setting:
Free living urban adults in ireland.Subjects: Fifty-one volunteers aged greater than or equal to 65 y.Interventions: Volunteers were each provided with capsules providing either 13.3 mg lycopene, or 11.9 mg carotene or placebo for 12 weeks.

Results:
Both absolute and cholesterol standardized plasma carotenoid concentrations correlated strongly with LDL and HDL concentrations of carotenoids before and after supplementation with carotene or lycopene. Supplementation with a carotene mixture or lycopene had no effect on oxidative modification of LDL in vitro despite significant increases in plasma and LDL concentrations of lycopene, alpha-carotene and beta-carotene.

Conclusions:
The results of this study suggest that, in unsupplemented individuals, plasma can act as a biomarker of carotenoid and gamma-tocopherol concentrations in both LDL and HDL. Supplementation with carotenes or lycopene do not reduce or delay oxidation of LDL. These results support the assumption that carotenoids, such as beta-carotene and lycopene, may show protective effects because they are good markers of fruit and vegetable intake.