ABSTRACT: The widespread detection of elevated oxidative stress levels in many medical conditions has led to numerous efforts to design interventions to reduce its effects. Efforts have been wide-ranging, from dietary changes to administration of antioxidants, supplements, e.g., omega-3-fatty acids, and many medications. However, there is still no systemic assessment of the efficacy of treatments for oxidative stress reduction across a variety of medical conditions. The goal of this meta-analysis is, by combining multiple studies, to quantitate the change in the levels of the popular oxidative stress biomarker 8-iso-prostaglandin F2? (8-iso-PGF2?) after a variety of treatment strategies in human populations. Nearly 350 unique publications with 180 distinct strategies were included in the analysis. For each strategy, the difference between pre- or placebo and post-treatment levels calculated using Hedges' g value of effect. In general, administration of antibiotics, antihyperlipidemic agents, or changes in lifestyle (g = -?0.63, -?0.54, and 0.56) had the largest effect. Administration of supplements, antioxidants, or changes in diet (g = -?0.09, -?0.28, -?0.12) had small quantitative effects. To fully interpret the effectiveness of these treatments, comparisons to the increase in g value for each medical condition is required. For example, antioxidants in populations with coronary artery disease (CAD) reduce the 8-iso-PGF2? levels by g =?-?0.34?±?0.1, which is quantitatively considered a small effect. However, CAD populations, in comparison to healthy populations, have an increase in 8-iso-PGF2? levels by g =?0.38?±?0.04; therefore, the overall reduction of 8-iso-PGF2? levels is ??90% by this treatment in this specific medical condition. In conclusion, 8-iso-PGF2? levels can be reduced not only by antioxidants but by many other strategies. Not all strategies are equally effective at reducing 8-iso-PGF2? levels. In addition, the effectiveness of any strategy can be assessed only in relation to the medical condition investigated.
