Oxygen radical absorbance capacity (ORAC): New horizons in relating dietary antioxidants/bioactives and health benefits

• Involvement of reactive oxygen species in cellular oxidation of biomolecules.
• Advantages/disadvantages of methods for assessing diet antioxidant capacity.
• Antioxidant capacity assays as tools for assessing dietary antioxidant intake.
• Diet intakes of ≥10,000 µmol TE per day (ORAC) have positive health effects.
• Opportunities for understanding oxidative stress using multiple radical sources.

The concept of oxidative stress, the factors responsible for oxidative stress and on those substances in foods that may have in vivo effects in terms of decreasing the adverse effects of reactive oxygen species (ROS) and reactive nitrogen species (RNS) on normal physiological function are reviewed. Methods of analysis of dietary redox reactive compounds and the role of dietary antioxidants in preventing disease are discussed. Literature related to the role of consumption of dietary bioactives (antioxidants) on the prevention of adverse health outcomes, with clinical trials in human subjects as the primary focus is reviewed.