Grant: Discovery Grants Program - Group

Oxidative stress results from an imbalance between the creation of pro-oxidants and their destruction by cellular defense mechanisms, including glutathione (GSH) metabolism.  Oxidative stress leads to damage to lipids, proteins and DNA, and is a final common pathway in many forms of disease.  Fruit and vegetable intake is known to be protective against many chronic diseases.  A possible mechanism for this protection is a reduction in oxidative stress since fruits and vegetables contain a large proportion of antioxidant polyphenols that directly neutralize reactive oxygen species.  We have recently shown that feeding polyphenol-rich extracts of wild blueberries to animals experiencing oxidative stress produces an increase in the GSH:GSSH ratio in liver and brain. Glutathione is the most important antioxidant, found in relatively high concentrations in most cells.  Thus, plant polyphenols appear to exert their beneficial effects on animals, by enhancing these internal antioxidant defenses.  How this occurs is not known.  Further, we know that polyphenols produce various metabolites in our bodies once ingested.  We suspect that it is these metabolites and not the original polyphenols that protect against chronic disease.  Together, the studies proposed should increase our understanding of the role of polyphenols from fruit and vegetables in the prevention of chronic disease.