#C118 Who Is Likely to Respond to Dietary Antioxidant Phytochemical Interventions? Henry Thompson,1 Jerianne Heimendinger,2 Scot Sedlacek,3 Albert Haegele,1 Ann Diker,1 Caitlin O'Neill,2 Becky Meinecke,1 Pamela Wolfe,1 Zongjian Zhu,1 Weiqin Jiang.1 Colorado State University,1 Ft. Collins, CO, AMC Cancer Research Center,2 Denver, CO, Rocky Mountain Cancer Centers,3 Denver, CO. A total of 267 women were enrolled in an 8-week dietary intervention to reduce oxidative stress, measured as the urinary excretion of 8-isoprostane F-2a (8-EPG), an index of whole-body lipid peroxidation; 208 women (78%) completed the study. The diets evaluated had comparable levels of all macronutrients and met national dietary guidelines but varied in their content of vegetables (V), fruits (F), and whole grains (WG). Study participants were given a cookbook containing menus and recipes that prescribed all the foods that were to be consumed during the study. Food records were maintained to document what was eaten. Following a 2-week run-in diet that was low in V, F, and WG, subjects were randomized to diets either high in VF (>10 servings per day) and low in WG or low in VF (<5 servings/day) and high in WG. At the initiation of the study and at 2-week intervals thereafter, samples of blood and 3 consecutive day first void urine specimens were obtained. The run-in diet reduced mean 8-EPG by 33%, and after 2 weeks on the two intervention diets, mean levels were further reduced by VF, but the difference between the two diet groups was not statistically significant. Further analysis revealed that the response to the dietary intervention was dependent on the baseline level of oxidative stress. Baseline levels of 8-EPG ranged from 160 to 7670 pg/ mg creatinine. The population was divided into quartiles (EPG<450, 450940 pg/mg creatinine) and the response of women in each quartile to the dietary interventions was assessed. A dramatic difference in response was observed depending on baseline level of 8-EPG. The greatest reductions in urinary 8-EPG were observed among individuals with the highest baseline levels of this analyte. After two weeks on the run-in diet, the mean 8-EPG in the highest quartile was reduced 47% (p<0.001), and in the lowest three quartiles, only 18% (p<=0.001). After 2 weeks on the study diets, the difference in mean 8-EPG between diet groups in the highest quartile was 205 pg, p=0.03. P-values are based on contrasts estimated in a repeated measures mixed model using the log transform of 8-EPG. No significant change in urinary excretion of 8-EPG was observed in individuals in the lowest quartile of baseline 8-EPG (4.5 and 8.0 % respectively in the low versus high VF intervention groups). The beneficial effect of the high VF diet seen after two weeks was maintained at the same levels thereafter. Interestingly, individuals in the highest baseline quartile of 8-EPG, despite experiencing dramatic reductions in the urinary excretion of this analyte, still remained higher in 8-EPG excretion than individuals in the lower three quartiles irrespective of the diets to which they were assigned throughout the 8-week intervention. The factors that account for differences observed in urinary excretion of 8-EPG are under investigation. Frontiers in Cancer Prevention Research, 2003 AACR Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.