Interactions between liposoluble antioxidants: A critical review.

Liposoluble antioxidants, including natural and synthetic antioxidants, are substances to prevent lipid oxidation. From previous studies, the interaction of antioxidants may be the main reason for the poor correlation between liposoluble phytochemicals and antioxidant activity in oils. This review brings together information concerning the types and mechanisms of antioxidant interactions in terms of structure and active groups. A critical summary of the interactions between liposoluble antioxidants (synergistic effects, antagonistic effects and additive effects) is given. Factors including the diverse structure, combinations with different concentrations or proportions, and the reaction system which affect the interactions between liposoluble antioxidants, along with the opportunities and challenges in future study are also discussed. However, the influencing factors and mechanism still require further investigation. It is proposed that the studies in whole foods system and in vivo along with the related interaction mechanism should be considered in future.

Antioxidant interaction of α-tocopherol, γ-oryzanol and phytosterol in rice bran oil.

In this study, purified rice bran oil (RBO) was used as a lipid matrix model to study the individual and binary antioxidant capacity of the minor constituents (α-tocopherol, γ-oryzanol and phytosterol) added at different concentrations and ratios. The results revealed that concentration influenced on the oxidation stability and scavenging capacity, while ratio mainly affected the type of interaction or the degree of synergism or antagonism. It was important to notice that the antioxidant capacity of α-tocopherol would decrease under high concentration. Besides, the inhibition of phytosterol on α-tocopherol and the formation of hydrogen bond between γ-oryzanol and phytosterol were speculated by the interactions of these minor constituents. This work helps to select efficient combinations for stabilizing the anti-oxidation of nutrient enriched RBO or provide suggestions for moderate retain of minor constituents in RBO.

[Study on the diet quality and its relative effect factors among rural residents, using the Chinese Diet Balance Index (CDBI) in Hanzhong, Shaanxi province].

OBJECTIVE: To evaluate the diet quality and the relative factors among rural residents in Hanzhong, Shaanxi province. METHODS: A cross-sectional survey on dietary status together with a semi-quantitative food frequency questionnaire were conducted on rural residents aged from 18 to 80 in Hanzhong of Shaanxi in 2010. Diet quality was evaluated by using the Chinese Diet Balance Index (CDBI) scoring and evaluating system. Linear regression models were developed to identify factors that influencing the status of under/over intake. RESULTS: 2748 rural residents were investigated with the average daily intake of grains, beans, heavily salted vegetables, plant oil, nuts and salt. Results showed that they were higher than average level of Chinese rural residents' (P < 0.01). 80% of the residents having their daily intake of grains, oil and salt exceeded, while animal food, diary food, egg, vegetable and fruits were lower (P < 0.01) than the RNIs. However, there was under intake noticed to some extent in some areas. The average values of DBI_LBS and DBI_HBS were 22.8 and 9.8. The proportions of moderate under intake (20 < DBI_LBS ≤ 40) and moderate over intake (10 < DBI_HBS ≤ 20) were 62.6% and 48.0%. The main factors that influenced the dietary under-intake were education level, fortune index, hypertension, physical activity, and time to watch television. The main factors that affected the over-intake of diet were sex, age, number of family numbers, intensity of labor, time to sleep, smoking and drinking habits. CONCLUSION: The main diet problem among the rural residents was under-dietary-intake, with over-intake to some extents, suggesting that it was necessary to strength the specific intervention program, to improve the diet quality in the residents of Hanzhong area.

Lutein supplementation reduces plasma lipid peroxidation and C-reactive protein in healthy nonsmokers.

OBJECTIVE: The aim of this study was to determine whether lutein affected biomarkers related to cardiovascular diseases (CVD) in healthy nonsmokers. METHODS: A randomized, double-blind, placebo-controlled trial of lutein supplementation was conducted in healthy nonsmokers. 117 eligible subjects were randomly assigned to receive 10 or 20 mg/d of lutein or placebo for 12 weeks. Levels of plasma carotenoid concentrations, total antioxidant capacity (TAOC), the lipoprotein profile, and antioxidant enzymes activities were determined at baseline and at 6, and 12 weeks after the initiation of treatment. Biomarkers of oxidative damage to protein and lipids, and C-reactive protein (CRP) concentrations were measured at baseline and after supplementation. RESULTS: Plasma lutein and TAOC significantly increased in both active treatment groups during 12 weeks. A significant reduction was found in malondialdehyde in the 20 mg lutein group. CRP concentration decreased in a dose-dependent manner for lutein supplementation, and there was a significant between-group difference in CRP between the 20 mg lutein and the placebo group. Serum CRP was directly related to the change in plasma lutein and TAOC for both active treatment groups. CONCLUSION: The results support the possibility that lutein supplementation reduce biomarkers of CVD risk via decreased lipid peroxidation and inflammatory response by increasing plasma lutein concentrations and antioxidant capacity.