Flavonoids and phenolic acids from cranberry juice are bioavailable and bioactive in healthy older adults.

Cranberries (Vaccinium macrocarpon) are a rich source of phenolic phytochemicals, which likely contribute to their putative health benefits. A single-dose pharmacokinetic trial was conducted in 10 healthy adults ⩾50y to evaluate the acute (24-h) absorption and excretion of flavonoids, phenolic acids and proanthocyanidins (PACs) from a low-calorie cranberry juice cocktail (54% juice). Inter-individual variability was observed in the Cmax and Tmax of many of these compounds in both plasma and urine. The sum total concentration of phenolics detected in plasma reached a peak of 34.2μg/ml between 8 and 10h, while in urine this peak was 269.8μg/mg creatinine, and appeared 2-4h earlier. The presence of PAC-A2 dimers in human urine has not previously been reported. After cranberry juice consumption, plasma total antioxidant capacity assessed using ORAC and TAP assays correlated with individual metabolites. Our results show phenolic compounds in cranberry juice are bioavailable and exert antioxidant actions in healthy older adults.