High-Pressurized Orange Juice Consumption Affects Plasma Vitamin C, Antioxidative Status and Inflammatory Markers in Healthy Humans

We examined the bioavailability of vitamin C in orange juice processed using high pressure (HP) and its effects on plasma levels of vitamin C, uric acid (UA), F2-isoprostanes (8-epiPGF(2alpha)), C-reactive protein (CRP) and prostaglandin E(2) (PGE(2)) in a healthy human population. Subjects (6 men, 6 women) enrolled in the study consumed 500 mL/d of HP orange juice for 14 d, corresponding to an intake of 250 mg of vitamin C. On d 1 of the study, subjects drank the juice in one dose; on d 2 until the end of the study, d 14, they drank 250 mL in the morning and 250 mL in the afternoon. Blood was collected every h for 6 h, on d 1, and then on d 7 and 14 of the study. Baseline plasma vitamin C concentration was higher (P = 0.014) in women (55.8 +/- 3.8 micro mol/L) than in men (42.8 +/- 2.1 micro mol/L). The maximum plasma vitamin C increase occurred 3 h after drinking the juice, and it remained elevated on d 7 and 14. Plasma 8-epiPGF(2alpha) concentration did not differ between men and women at baseline. However, it was lower at the end of the study in both men (P = 0.044) and women (P = 0.034). Plasma levels of vitamin C and 8-epiPGF(2alpha) were inversely correlated (r = -0.615, P = 0.001). Plasma CRP concentrations tended to be lower on d 14 than at baseline in men (P = 0.317) and women (P = 0.235). Plasma PGE(2) was lower at the end of the study in both men and women (P <or= 0.037). Drinking orange juice increases plasma vitamin C, and decreases 8-epiPGF(2alpha) and PGE(2) levels in humans, which may help reduce the risk of chronic diseases.