Biomarker-estimated Flavanol Intake in Davis (FID)

Flavanols are compounds present in plants, including apples, berries, peaches, cocoa-derived products and certain beverages like tea. Following intake, they are absorbed and broken down into smaller compounds called 'metabolites'. Some of these metabolites are excreted in urine. In this study, we hope to collect urine and examine the metabolites to learn more about the types and amounts of flavanols that people are consuming as part of their usual diet.

Flavanols, including the monomers (-)-epicatechin and (+)-catechin, and their related oligomeric derivatives, the procyanidins, are a group of plant-derived, dietary bioactives amply present in the diet. Supported by accumulating epidemiological studies and outcomes from the first large-scale randomized study with bioactives, the COcoa Supplement and Multivitamin Outcomes Study (COSMOS), the Academy of Nutrition and Dietetics released the first dietary recommendation for flavan-3-ols intake in the United States (US). This recommendation suggests the consumption of 400-600 mg/d of flavan-3-ols to mediate cardiometabolic beneficial effects, including the reduction of cardiovascular disease risk. While previous studies have aimed at assessing dietary intake of this group of bioactives, the tools used for these assessments were based on dietary questionnaires and food content databases. These tools are subjective and known to present significant limitations. Recently, our laboratory developed a series of nutritional biomarkers to objectively assess flavanol intake and thus, overcome limitations inherent to previous methods. These biomarkers are based on the quantification of a series of flavanol metabolites, including the 5-(3,4-dihydrophenyl)-γ-valerolactone metabolites (gVLM) and the structurally related (-)-epicatechin metabolites (SREMs). These biomarkers provide complementary information; as while gVLM provide information about the intake of flavanols in general, SREMs are specific biomarkers of (-)-epicatechin intake. In addition, gVLM are surrogate biomarkers, which means that this biomarker allows ranking volunteers from low to high flavanol consumers without providing information on absolute intake. On the other hand, SREMs proved to perform as a recovery biomarker when assessed in 24-hour urine, thus providing absolute amount of (-)-epicatechin consumed. While gVLM and SREM biomarkers have been used to assess the intake of flavanols and epicatechin in the United Kingdom, little is known about biomarker-estimated intake of flavanols in the US, and even less when considering the use of SREM as a recovery biomarker. Therefore, the characterization of flavanol and epicatechin intake in a US population will provide essential information to understand efforts to promote flavanol intake based on current dietary recommendations and thus increase access of the health benefit related to the consumption of these bioactives to the public in general.