Absorption and Metabolism of Dietary Cocoa Procyanidins in Humans

Flavanols and their oligomeric derivatives, the procyanidins, are plant-derived compounds normally present in the human diet. Accumulating data demonstrate a causal role for flavanols in mediating the cardiovascular benefits associated with the consumption of flavanol-/procyanidin-containing foods. Evidence for a direct, causal role for procyanidins in this context is far less profound. As this is often based on the poor absorption of procyanidins, it has been proposed that procyanidins may indirectly contribute to the systemic presence of bioactive compounds via derivatives generated from the breakdown or catabolism of procyanidins in the gastrointestinal tract. These postulated 'breakdown products' include: i) flavanols, putatively generated by acid hydrolysis in the stomach, and ii) series of phenolic compounds, including 5-(3,4-dihydroxyphenyl)-gamma-valerolactone, that are produced from procyanidin catabolism by the gut microbiome. Verification or rejection of these suppositions could significantly impact the interpretation of epidemiological-/dietary intervention data, and the design of food-content data bases. To address this question, healthy volunteers will consume specially designed cocoa-based dairy drinks containing flavanols and procyanidins (dimers to decamers) either together or individually.

Inclusion criteria

• A normal blood chemistry and liver function
• Fasting blood cholesterol and triglycerides < 300 mg/dl and < 3.0 mmol/l, respectively
• BMI < 30 kg/m2 will be considered.
• Volunteers must be able to read and speak English fluently, and thus, fully understand the researchers, research protocols, and their rights as a research volunteer.

Exclusion criteria

• A history of cardiovascular disease, stroke, uncontrolled hypertension (> 160/90 mm), renal, hepatic, or thyroid disease, GI tract disorders, previous GI surgery, metabolic syndrome, diabetes, taking cholesterol-lowering medication, hormone replacement therapy, antioxidant supplements, on aspirin therapy or taking anticoagulants, or on a medically prescribed diet.
• A history of psychiatric illness or an allergy to peanuts.