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

Abstract

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 ≥65 y.

Design: Randomized placebo controlled double blind study.

Setting: Free living urban adults in Ireland.

Subjects: Fifty-one volunteers aged ≥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, α-carotene and β-carotene.

Conclusions: The results of this study suggest that, in unsupplemented individuals, plasma can act as a biomarker of carotenoid and γ-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 β-carotene and lycopene, may show protective effects because they are good markers of fruit and vegetable intake.

Sponsorship: Commission of the European Communities: AAIR Project (AIR2-CT93-0888).

European Journal of Clinical Nutrition (2000) 54, 500–507