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Objective To study oxidative stress indicators in healthy young children and their response to a commercially available fruit- and vegetable-based antioxidant supplement. Design Healthy children were randomly assigned to a placebo and a supplement (commercial antioxidant supplement produced from dried fruit and vegetable extracts and fortified with antioxidants, resembling a gummy-type candy), The placebo and the supplement were taken in 2 doses per day for 21 days. Subjects Participants were 39 children (26 boys and 13 girls) aged 5 to 10 years. Research was conducted at Primary Children's Medical Center and the University of Utah, Salt Lake City. Main outcome measures Breath and urine samples were collected on days 1 and 21 and assayed for breath pentane and urine 8-hydroxydeoxyguanosine, malondialdehyde, nitrites, and 8-isoprostane as noninvasive indicators of oxidative stress. Urine oxygen radical absorbance capacity was measured at days 1 and 21 as an indirect indicator of the antioxidant capacity of the body. Three-day food records were collected at the beginning and end of the study to measure intake of dietary fruit; vegetable; and antioxidant vitamins A, C, and E. Statistical analysis Descriptive statistics, repeated measures analysis of variance, paired t tests, and Pearson r correlations. Results Markers of oxidative stress were not significantly different between the placebo and supplement groups at day 1 or day 21. The oxidative stress indicators of the healthy children in this study appear to be similar to those of healthy adults and were not changed by antioxidant supplementation. The diet record analyses indicated that mean fruit and vegetable intakes (2.75 servings/day) were similar to the national average intake for children in the United States. Applications/conclusions This research presents original information on the subject of oxidative stress in healthy children. The results of this study may be useful as reference baseline markers to use in conjunction with clinical dietary evaluations and for future research with healthy children and with children in disease states who are subject to elevated levels of oxidative stress. J Am Diet Assoc. 2002;1021 652-1657., Oxidative stress is a physiological condition in which prooxidant factors outweigh antioxidant defenses and may be part of a disease process or natural aging. Cells can respond to mild oxidative [...]

BACKGROUND: Fruits and berries are known to contain relatively high amounts of antioxidant/bioactive compounds. Several methods have been used for measurement of antioxidant capacity (AC), but not all methods have direct relevance to in vivo antioxidant status. OBJECTIVE: Determine AC in berry/fruit samples, processed berry products, and purified compounds by utilizing 5 different biologically relevant free radical/oxidant sources. METHODS: Samples were assayed for AC capacity using 5 different free radical/oxidant sources: peroxyl radical (ORAC), hydroxyl radical (HORAC), peroxynitrite (NORAC), superoxide anion (SORAC) and singlet oxygen (SOAC)]. Total AC (sum of AC with 5 individual radicals) was expressed as Oxygen Radical Absorption Capacity using Multiple Radicals (ORACMR5). RESULTS: SOAC contributed more than 60% of ORACMR5 in blackberries, sweet and tart cherries; and no detectable levels of SOAC were found in strawberries, black currants and raspberries. Whole fruit purees of mango, wild blueberry and cherry contained 95, 85 and 67% respectively of total ORACMR5 from SOAC. However, freeze dried wild blueberry powder from same production season had only 28% as SOAC and 42 and 22% as ORAC and HORAC. Blueberry/Pomegranate and Mango/Pineapple smoothies had 67% and 77% of ORACMR5 as SOAC. CONCLUSIONS: The antioxidant quenching potential using 5 different radical/oxidant sources of different berries and fruits varied widely and understanding this variation may be helpful in understanding health benefits of different berries and foods. [ABSTRACT FROM AUTHOR]