Fruit and Vegetable Supplementation - Effect on Ex Vivo LDL Oxidation in Humans

Carotenoid actions and their relation to health and disease

“…A 12 week period of daily supplementation with either 13 mg lycopene or 112 mg b-carotene resulted in an increase in LDL carotenoids, but no change in LDL oxidizability (Carroll et al, 2000). Similar results were seen with lutein supplementation for 1-2 weeks that resulted in a 4-6-fold increase in serum lutein but was without effect on LDL lag time (Chopra et al, 1996). Also, when tomato juice was used as a supplement in a volunteer, there was a decrease in the rate of accumulation of cholesterol ester hydroperoxides when the isolated LDL particles were subjected to singlet oxygen oxidation, but no difference was observed when the LDL was treated with the radical initiator, AAPH (Oshima et al, 1996).…”

“…Lycopene from tomato-based products was reported to be effective (Agarwal and Rao, 1998) whereas pure lycopene supplementation was ineffective (Dugas et al, 1999). In addition, two other studies have not been able to verify that fruit and vegetable supplementation alters LDL resistance to oxidation (Chopra et al, 1996;van het Hof et al, 1999).…”

Antioxidant Properties of Carotenoids In Vitro and In Vivo

“…Recent clinical trials concluded that short-term dietary supplementation of healthy volunteers with lycopene-rich products (providing $ 30-50 mg lycopene/d) increased resistance of LDL to oxidative deterioration, as evaluated by various methods, such as determination of thiobarbituric acid reactive substances (TBARS) or conjugated dienes (CD) at 233 nm Bub et al, 2000;Steinberg and Chait, 1998;Upritchard et al, 2000). However, a lutein supplement dispersed in sunflower oil (30 mg/d for 2 weeks) did not significantly change ex vivo LDL oxidation (Chopra et al, 1996). Hininger et al (1997) reported an inhibition of LDL susceptibility to oxidation after a carotenoid-rich food intake for 2 weeks (providing an additional daily amount of 10 mg a-carotene, 10 mg b-carotene, and 10 mg of lutein).…”

Antioxidants and lipoprotein metabolism

“…Whether this reduction in carotenoid levels could have accounted for the reduction in the lag phase is not known. There was no correlation between the carotenoid levels and the lag phase, but in most in vivo supplementation studies with carotenoids there is usually no increase in the lag phase (Gaziano et al 1995;Chopra et al 1996).…”

“…Results from in vivo supplementation studies with carotenoids have not been encouraging. Most studies fail to show protection of LDL after in vivo supplementation with carotenoids (Gaziano et al 1995;Nenster et al 1995;Chopra et al 1996). Levy et al (1995) reported that the trans-isomer of β-carotene is more effective in protecting LDL than the cis-isomer.…”