Moderate Intervention with Carotenoid-Rich Vegetable Products Reduces Lipid Peroxidation in Men

Abstract

Because of their antioxidant properties, carotenoids may have beneficial effects in preventing cancer and cardiovascular disease. However, in humans consuming carotenoid-rich vegetables, data concerning the antioxidant effects of carotenoids are rather scarce. A human intervention trial was conducted, therefore, to determine whether a moderately increased consumption of carotenoid-rich vegetables would influence the antioxidant status in 23 healthy men. This short-term feeding study lasted 8 wk during which the men consumed a low carotenoid diet. A 2-wk low carotenoid period was followed by daily consumption of 330 mL tomato juice, then by 330 mL carrot juice and then by 10 g of spinach powder, each for 2 wk. Antioxidant status [water-soluble antioxidants in serum, ferric reducing ability of plasma (FRAP) and antioxidant enzyme activities] and lipid peroxidation (plasma malondialdehyde and ex vivo oxidation of LDL) were determined. In a subgroup of 10 men, lipoprotein carotenoids were measured. The consumption of carotenoid-rich vegetables significantly increased selected carotenoids in lipoproteins but had only minor effects on their relative distribution pattern. Tomato juice consumption reduced plasma thiobarbituric acid reactive substances (TBARS) by 12% (P Ͻ 0.05) and lipoprotein oxidizability in terms of an increased lag time (18%, P Ͻ 0.05). Carrot juice and spinach powder had no effect on lipid peroxidation. Water-soluble antioxidants, FRAP, glutathione peroxidase and reductase activities did not change during any study period. In evaluating the low carotenoid diet, we conclude that the additional consumption of carotenoid-rich vegetable products enhanced lipoprotein carotenoid concentrations, but only tomato juice reduced LDL oxidation in healthy men.

Tomatoes versus lycopene in oxidative stress and carcinogenesis: conclusions from clinical trials

“…Hininger et al (2001) further supplemented healthy male volunteers with 15 mg of natural tomato lycopene extracts for 12 weeks, and reported no effects on LDL oxidizability. In comparison with these studies showing null effects of tomato lycopene supplementation on lipoprotein oxidation, Bub et al (2000) reported a 18% increase in LDL lag time in 23 healthy men, following a 2-week tomato juice consumption providing a higher dose of lycopene (40 mg/day). It should also be noted that following a 2-week carotenoid depletion period, the plasma lycopene levels in these healthy volunteers were reduced to a concentration of 0.16 mmol/l of all-trans lycopene and 0.15 mmol/l of cis-lycopene.…”

Effects of enhanced consumption of fruit and vegetables on plasma antioxidant status and oxidative resistance of LDL in smokers supplemented with fish oil

“…However, the beneficial effects of this level of consumption have not been examined. Studies to date have concentrated on dietary enhancement of volunteers with carotenoid-rich vegetables (Hininger et al, 1997;van het Hof et al, 1999;Bub et al, 2000;Chopra et al, 2000) or provided subjects with a highly controlled diet with a very high fruit and vegetable component (9-10 servings per day) (Cao et al, 1998;Miller et al, 1998). Previous studies attempting to increase fruit and vegetable consumption in free-living volunteers demonstrated increases in plasma antioxidants (Zino et al, 1997), but no significant increase in plasma antioxidant capacity (Record et al, 2001).…”

Oxidation resistance of exogenous melatonin on leaves of kiwifruit seedlings under copper stress

“…The plant itself can protect the cell from oxidative damage by the non-enzymatic antioxidant system to eliminate excessive reactive oxygen species formed under adverse conditions [12]. When there are antioxidants for hydrogen production (such as phenols), the color of DPPH solution becomes shallow; ABTS •+ reacts with it and turn it into a colorless ABTS; And FRAP measures the antioxidant capacity of power by measuring the ability of Fe 3+ to be reduced to Fe 2+ [13]. The results showed that exogenous melatonin treatment increased the content of TPC, TFC, TFAC, AsA in leaves of kiwifruit seedlings, enhanced the antioxidant ability.…”