Both red and blond orange juice intake decreases the procoagulant activity of whole blood in healthy volunteers.

Aim: Numerous epidemiological studies suggest that exposure to flavonoid-rich fruits has beneficial influence on risk factors for cardiovascular disease. We investigated whether intake of orange juice (OJ) could affect whole blood (WB) procoagulant activity.

Methods: 17 healthy subjects (aged 31 ± 1.5 SEM 10 males) were randomized to receive, according to a cross-over design, either red or blond OJ, enriched or free of anthocyanins, respectively. After one week run-in period on a controlled diet, the subjects were randomly allocated to receive either type of OJ for 4 weeks, with a 4-week wash-out period. Venous blood was collected on citrate before and at the end of each treatment period. WB was incubated with or without an inflammatory stimulus (tumor necrosis factor-α or bacterial endotoxin LPS). Procoagulant activity was evaluated by a one-stage clotting assay. Tissue factor (TF) and TF pathway inhibitor (TFPI) were measured in plasma by ELISA.

Results: Intake of either type of OJ caused a prolongation of unstimulated and stimulated WB clotting times, without any difference between the two treatments. Intake of OJ did not modify TF levels. On the contrary, an increase in circulating TFPI antigen was detected following either treatment.

Conclusions: Orange juice intake by healthy volunteers decreases procoagulant activity, possibly through mechanisms independent of its anthocyanin content.