The Healthy Lion Award Lecture-2013
Consumption of polyphenol rich foods and beverages has been associated with several health benefits including a reduced risk of several chronic and degenerative diseases. Flavan-3-ol monomers and polymers, common to apple, tea, cocoa and grape products, are the most abundant dietary polyphenol forms in the US diet. These polyphenol forms have demonstrated biological activities consistent with health promoting effects including the ability to modulate oxidative and inflammatory stress, detoxification pathways and improve endothelial function. While promising, physiological delivery (bioavailability) of flavan-3-ols or their bioactive metabolites from foods to target tissues remains the critical step required to positively affect disease risk and outcomes. Ultimately, bioavailability of flavan-3-ols is limited by several factors including (1) flavan-3-ol form and food matrix composition; (2) potential sensitivity to small and large intestinal conditions; (3) poor transport in the intestinal epithelia; (4) rapid intestinal and hepatic metabolism and (5) adaptation to repeated dietary exposure. The food matrix itself is known to impact multiple factors critical to bioavailability of flavan-3-ol from foods and beverages. Specifically, product composition, chronic or repeated exposure and path-physiological status may influence the transit and reactivity within the gut lumen, absorption mechanisms and metabolism of individual bioactive flavan-3-ol derivatives from foods and dietary supplements. Additionally, co-formulation with ascorbic acid, carbohydrates, and potentially proteins can be strategically applied to modulate digestive release, intestinal absorption and ultimate bioavailability of flavan-3-ols. Finally, consideration of the impact of dose duration and pathophysiological status on delivery of polyphenol forms remains an evolving area of research. Understanding how these factors can collectively impact polyphenol profiles and their bioavailability allows for the design of foods, beverages and dietary supplements consistent with delivery of bioactive polyphenol forms and their desired health benefits.