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Human Nutrition and Metabolism

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

Concepción Sánchez-Moreno^*,, M. Pilar Cano, Begoña de Ancos, Lucía Plaza, Begoña Olmedilla^**, Fernando Granado^** and Antonio Martín^*,2

^* Nutrition and Neurocognitive Laboratory, Jean Mayer U.S. Department of Agriculture-Human Nutrition Research Center on Aging at Tufts University, Boston, MA; Department of Plant Foods Science and Technology, Instituto del Frío-CSIC, Madrid, Spain; and ^** Unit of Vitamins, Section of Nutrition, Clínica Puerta de Hierro, Madrid, Spain

²To whom correspondence should be addressed. E-mail: antonio.martin{at}tufts.edu.

	ABSTRACT

TOP ABSTRACT SUBJECTS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 
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-epiPGF₂), C-reactive protein (CRP) and prostaglandin E₂ (PGE₂) 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 µmol/L) than in men (42.8 ± 2.1 µmol/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-epiPGF₂ 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-epiPGF₂ 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 PGE₂ was lower at the end of the study in both men and women (P ≤ 0.037). Drinking orange juice increases plasma vitamin C, and decreases 8-epiPGF₂ and PGE₂ levels in humans, which may help reduce the risk of chronic diseases.

KEY WORDS: • high-pressurized orange juice • vitamin C • F2-isoprostanes • C-reactive protein • prostaglandin E₂

Consumption of fruits and vegetables has been associated with reduced risks of certain diseases (1,2). Citrus juices, especially orange juice and grapefruit juice, are rich sources of vitamin C. Recent reports suggested that drinking generous amounts of a mixture of various juices improves the blood lipid profile, reduces oxidative stress and prevents atherogenic modifications of LDL cholesterol and platelet aggregation (3,4).

Oranges are an excellent source of vitamin C. Orange juice is traditionally pasteurized by heat treatment at 95°C for 15 s or 90°C for 1 min (5). Vitamin C is vulnerable to air and heat. Therefore, it is important to develop new technologies that minimize the conservation processes and guarantee the microbiological environment to obtain a product that is stable and additive free, with minimum food chemical modification (6,7). Recent studies have confirmed that hydrostatic high pressure (HP) is an effective nonthermal processing procedure for the stabilization of freshly squeezed orange juice (7,8). However, no study has examined the bioavailability of vitamin C in HP orange juice and its possible beneficial effects on levels of oxidative stress [F2-isoprostanes (8-epiPGF₂)], uric acid (UA) and inflammatory markers [C-reactive protein (CRP) and prostaglandin E₂ (PGE₂)].

Antioxidant nutrients have important roles in cell function and have been implicated in processes associated with aging, including vascular and inflammatory damage. By acting as antioxidants and at the molecular level, vitamins E and C can participate in preserving cell membrane composition and function, protect molecules such as cholesterol and DNA from oxidative damage, and consequently improve human health and decrease chronic disease (9,10). Vitamin C improves lysosomal function (2), acts as a cofactor for dopamine-ß-hydroxylase (11), mediates glutamate uptake (12) and contributes to preserve a healthy vasculature through the regulation of collagen synthesis, prostacyclin production and maintenance of nitric oxide levels (13–15). The second National Health and Nutrition Examination Survey reported that low intake of vitamin C is associated with blood levels ≤ 0.3 mg/dL (17 µmol/L) (16), whereas well-nourished people tend to have blood levels that fluctuate between 0.8 and 1.3 mg/dL (45–74 µmol/L). Fruits and vegetables are the main sources of vitamin C, but 25% of women and 33% of men eat <2.5 servings of fruits and vegetables daily to provide 80 mg/d of vitamin C.

8-epiPGF₂ belongs to a family of eicosanoids of nonenzymatic origin produced by the random oxidation of phospholipids by oxygen radicals and are elevated by oxidative stress (17). One of the isoprostanes, the 8-epiPGF_2, has been shown to act as a vasoconstrictor (18) and to be associated with hepatorenal syndrome (19) and pulmonary oxygen toxicity (20). Previous studies have shown decreased levels of antioxidants and high concentrations of 8-isoprostanes associated with chronic diseases (21).

Hyperuricemia may have a direct injurious effect on the endothelium, altering endothelial cell function and reducing nitric oxide bioavailability, relevant in the development of vascular dysfunction and cardiovascular risk. In fact, elevated serum UA concentration appears to be an important risk factor in predicting myocardial infarction (22).

Plasma CRP levels have recently been identified as an emerging risk factor for ischemic heart disease. Results from cross-sectional and prospective studies have indicated that raised plasma CRP levels are associated with an increased risk for future cardiovascular events among apparently healthy subjects (23).

PGE₂ is a primary product of arachidonic acid metabolism in many cells. When cells are activated, PGE₂ is synthesized de novo and released into the extracellular space. Elevated PGE₂ concentration can contribute to the decline in T-cell function. In fact, marginal vitamin E deficiency has been reported to impair the immune response, whereas supplementation of vitamin E enhances the immune response (24); these effects seem to be mediated through modulation of PGE₂ levels.

No studies exist that have carefully investigated the bioavailability of vitamin C from HP orange juice and its potential effect on oxidative and inflammatory status. Therefore, the objectives of this study were to assess the bioavailability of vitamin C from high-pressurized orange juice and its effect on 8-epiPGF₂ levels, and on CRP and PGE₂ levels in a healthy human population.

	SUBJECTS AND METHODS

TOP ABSTRACT SUBJECTS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 
Subjects.

Twelve healthy volunteer subjects (6 men, 6 women) were enrolled in this study. The subjects were between 20 and 32 y old (22 ± 3); the mean BMI was 22.2 ± 1.6 kg/m² and did not change during the study. All of the subjects continued their habitual diets during the study. Subjects were taking no vitamin/mineral supplements and no medications. None of the subjects were pregnant, lactating or had any chronic illness. All study participants were in good health on the basis of a medical history, a physical examination and normal results from clinical laboratory tests, including triglycerides (0.9 ± 0.3 mmol/L), cholesterol (4.4 ± 1.1 mmol/L), glucose (4.8 ± 0.4 mmol/L) and hematocrit (0.44 ± 0.03). Subjects received oral and written information about the study and gave their written consent. The study was approved by the Clinic Research Ethics Committee of Hospital Universitario Clínica Puerta de Hierro, Madrid, Spain.

Study design.

The vitamin C bioavailability study was divided into two components: a dose-response test and a multiple-dose response. For the dose-response evaluation, after a minimum of 12 h of fasting, an intravenous catheter was inserted into the forearm and blood was drawn before and every 60 min for 6 h after subjects drank the juice. Blood samples were collected in heparin-coated tubes and centrifuged at 2000 x g for 15 min at 4°C. After plasma was collected, aliquots in triplicate were immediately mixed with an equal volume of cold 60 g/L metaphosphoric acid containing 1 mmol/L of the metal ion chelator diethylenetriaminepentaacetic acid, for vitamin C and UA acid analysis. The rest of the plasma was stored at -80°C for 8-epiPGF₂, CRP and PGE₂ analysis. After taking blood samples at baseline, defined as t0, volunteers consumed 500 mL of HP orange juice and blood samples were taken every 60 min, which corresponded to the times t1, t2, t3, t4, t5 up to 6 h or t6 (dose-response test evaluation). Then, the subjects were instructed to drink the juice at home, in two doses, 250 mL in the morning and 250 mL in the afternoon, for 2 consecutive weeks. Blood samples were taken again during the intervention on d 7 and 14 of the study.

The composition of the HP orange juice consumed by the participants was analyzed by reversed-phase HLPC with methods currently used in our laboratory (8,25,26); the main components are reported in Table 1.

Freshly squeezed orange juice was obtained from orange fruits (Citrus sinensis L.), variety Navel Late (Spain), purchased in a local supermarket, using a squeezer (Lomi mod. 4, Madrid, Spain) and filtered through 2-mm steel sieves. The orange juice was vacuum-packed in plastic bags (Doypack) and then introduced into the pressure unit filled with pressure medium (water) to stabilize fresh orange juice using a HP treatment. The HP treatment was performed in a hydrostatic pressure unit with a 2350 mL capacity, a maximum pressure of 500 MPa and a potential maximum temperature of 95°C (Gec Alsthom ACB 900 HP, type ACIP 665, Nantes, France). On the basis of our previous studies (8,26), the conditions used in the HP treatment were 400 MPa at 40°C for 1 min. After treatment, orange juice was kept at 4°C until the participants drank it.

Vitamin C determination in plasma.

Ascorbate was analyzed by paired-ion, reversed-phase HPLC coupled with electrochemical detection as previously described by Martin et al. (27). Peaks were integrated with a ChemStation (Hewlett-Packard, Wilmington, DE). Ascorbate concentration was calculated on the basis of a calibration curve, and its concentration expressed in µmol/L.

8-Isoprostane (8-epiPGF₂) determination.

We used an enzyme immunoassay (EIA) kit to determine 8-epiPGF₂ (28). This assay is based on the competition between 8-isoprostane and an 8-isoprostane-acetylcholinesterase conjugate (8-isoprostane tracer) for a limited number of 8-isoprostane–specific rabbit antiserum binding sites. The rabbit antiserum-8-isoprostane (either free or tracer) complex binds to the rabbit IgG mouse monoclonal antibody that has been previously attached to the well. First, we gently mixed the samples (0.5–1 mL) with 50 µL of affinity sorbent (mouse anti-8-isoprostane covalently bound to Sepharose 4B) for 60 min at room temperature to purify samples. After incubation of 500 µL plasma with sorbent, samples were briefly centrifuged at 11,750 x g to sediment the sorbent (Cayman Chemical, Ann Arbor, MI). The sorbent, which contains the bound 8-isoprostane was resuspended in 300 µL of ethanol. The samples were vortexed briefly, then centrifuged at 11,750 x g to sediment the sorbent. We then collected the supernatant containing the 8-isoprostane. The wash process was repeated a second time and all washes were combined. The combined ethanol washes were evaporated to dryness in a vacuum centrifugation and then immediately dissolved in a 125 µL EIA buffer. Samples were then analyzed in duplicate using EIA. The concentration of 8-isoprostane in the test samples was interpolated from the standard curve using log transformation (20).

Uric acid determination.

We analyzed UA by paired-ion, reversed-phase HPLC coupled with electrochemical detection using the same procedure described for vitamin C determination with the electrode potential of +0.6 V but with the gain set at 1 µA (27).

C-reactive protein determination.

Plasma concentrations of CRP were measured with an ultrasensitive immunoassay using monospecific polyclonal and monoclonal antibodies as described in the method of Wilkins et al. (29).

Prostaglandin E₂ (PGE₂) determination.

PGE₂ was measured using a high sensitivity immunoassay based on a competitive binding technique in which PGE₂ present in a sample competes with a fixed amount of alkaline phosphatase-labeled PGE₂ for sites on a mouse monoclonal antibody. During the incubation, the mouse monoclonal antibody becomes bound to the goat anti-mouse antibody coated onto the microplate wells. After a wash to remove excess conjugate and unbound sample, we added a substrate solution to the wells to determine the bound enzyme activity. The intensity of the color, therefore, was inversely proportional to the concentration of the PGE₂ measured in the sample (30). The concentration of PGE₂ in the samples was interpolated from the standard curve using log transformation, and the results were expressed in ng/L.

Statistical analysis.

All values are presented as mean ± SEM. Repeated-measures ANOVA comparing the concentrations of vitamin C, 8-epiPGF₂, UA, CRP and PGE₂ between sexes and at different times of intervention was performed using Systat 10 (SPSS, Chicago, IL). When sex x time or sex differences were detected, Tukey’s Honestly Significant Difference test was run to determine differences at various time points between and within groups. The correlations among variables were examined by linear regression or by Spearman’s correlation as appropriate also using the Systat program. Differences were considered significant at P < 0.05.

	RESULTS

TOP ABSTRACT SUBJECTS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 
Baseline plasma levels of vitamin C were higher (P = 0.014) in women than in men (Table 2), in agreement with a previous study from our research group (31). During d 1 of the intervention, 3 h (maximum peak) after drinking the orange juice (500 mL) containing 250 mg of vitamin C, plasma levels increased by 86% (79.6 ± 4.3 vs. 42.8 ± 2.1 µmol/L) in men (P < 0.001), and by 79% (100.0 ± 3.0 vs. 55.8 ± 3.8 µmol/L) in women (P < 0.001), (Fig. 1). Subjects continued to drink the same amount of HP juice daily (500 mL) over the next 14 d. However, on d 2 of the intervention, subjects started drinking the juice in two servings, half in the morning and half in the afternoon.

View this table: [in this window] [in a new window]   TABLE 2 Plasma vitamin C, 8-isoprostane (8-epiPGF2), uric acid, C-reactive protein (CRP) and prostaglandin (PG) E2 concentration at baseline and on d 7 and 14 of drinking high-pressurized (HP) orange juice daily for 14 d in men and women1, 2

View larger version (17K): [in this window] [in a new window]   FIGURE 1 Plasma vitamin C concentrations in men and women at baseline (t0) and at 1 (t1), 2 (t2), 3 (t3), 4 (t4), 5 (t5) and 6 h (t6) after drinking 500 mL of orange juice processed under high pressure (HP) containing 250 mg vitamin C. Values are means ± SEM, n = 6. There was a significant main effect of sex, but no sex x time interaction (ANOVA). #In both men and women, times 0 and 1 differed from all other times, P < 0.05.

Baseline 8-epiPGF₂ concentrations did not differ between men and women (Table 2). An important finding of this study was the decrease in the plasma levels of 8-epiPGF₂ in men (P = 0.044) and women (P = 0.034) on d 14 of the intervention (Table 2). Supporting previous studies, we also found an inverse correlation between levels of vitamin C and 8-epiPGF₂ concentrations in both men and women at baseline (t0) and on d 14 (r = -0.615, P = 0.001) (Fig. 2).

View larger version (12K): [in this window] [in a new window]   FIGURE 2 Inverse correlation between plasma 8-epiPGF2 and vitamin C concentrations at baseline (t0) and at d 14 of drinking orange juice processed under high pressure (HP) in 6 men and 6 women (n = 24).

Baseline plasma CRP levels were normal (≤1.5 mg/L) in men and women. By d 14 of the intervention, plasma levels tended to be lower in both men (P = 0.317) and women (P = 0.235) (Table 2).

Baseline PGE₂ plasma levels were higher in men than in women. Interestingly, on d 14 of intervention, plasma levels of PGE₂ decreased in both men (P = 0.037) and women (P = 0.025) (Table 2).

	DISCUSSION

TOP ABSTRACT SUBJECTS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 
In this work, we have shown for the first time that drinking two glasses of HP orange juice (500 mL) daily increases the concentration of vitamin C in blood in both men and women by 86 and 79%, respectively, and significantly decreases 8-epiPGF₂ levels and PGE₂ concentrations. These vitamin C-mediated effects suggest that vitamin C from orange juice may play a critical role in reducing the formation of compounds produced by random oxidation of phospholipids and ameliorating inflammatory processes relevant to the development of chronic disease. We do not reject the possibility that other nutrients present in the HP orange juice may also have contributed to the beneficial effects.

Vitamin C is an essential nutrient involved in a large number of cellular processes. However, unlike most mammals, humans are unable to synthesize vitamin C and must therefore acquire it from diet. There are no studies documenting the bioavailability of vitamin C from orange juice, including from HP orange juice. Recently, various studies have examined plasma kinetics of flavanones after drinking orange and grapefruit juice, but they did not study the effect on plasma vitamin C levels (32). A recent study showed a 64% increase in plasma vitamin C concentration after ingestion of a mixture of fruits and vegetables (500 g) for 4 wk (33). We showed that taking 250 mg of vitamin C contained in two glasses of HP orange juice (500 mL), significantly increased plasma vitamin C concentration from a baseline of 30–50 µmol/L to 60–100 µmol/L in only 3 h after drinking the juice, and remained elevated as long as subjects were drinking the orange juice. Interestingly, blood levels of vitamin C > 49 µmol/L have been associated with a 64% reduction in the risk of cataract (34). Vitamin C is an essential cofactor in neurotransmitter synthesis (35) and is important in preserving endothelial-dependent vascular function (36). In fact, epidemiologic studies have shown that a high consumption of fruits and vegetables is associated with a decreased risk of chronic diseases, including dementia (12,37).

Ascorbic acid is also an efficient scavenger of superoxide anions and plays an important role in control of the intracellular redox state (38). Therefore, in this study, we evaluated the effect of vitamin C on the formation of F2-isoprostanes. These compounds are formed nonenzymatically through free radical–catalyzed attack on esterified arachidonic acid after its enzymatic release from cellular or lipoprotein phospholipids. F2-isoprostanes can be produced in abundance in vivo by peroxidation of arachidonic acid from phospholipids, catalyzed by free radicals independent of the cyclooxygenase enzyme (39). The 8-isoprostane, also referred to as 8-epiPGF₂ has received considerable attention due to its vasoconstrictive, platelet activation, and mitogenic properties (40). In fact, F2-isoprostanes provide an accurate way to measure oxidative stress in vivo. Several recent studies have assessed changes in F2-isoprostanes concentration in relation to health status and different pathological processes (41,42). Interestingly, we observed a significant decrease in 8-epiPGF₂ levels after subjects drank the HP orange juice daily, and a significant inverse correlation between plasma vitamin C and 8-epiPGF₂ levels. Other studies have also reported changes in 8-isoprostane levels after vitamin C and/or E supplementation (43,44).

A multivariate analysis of data from the MONICA cohort of 1044 men showed a significant association between high serum UA and cardiovascular mortality (45). Several mechanisms, including increased platelet adhesiveness and platelet lysis, vascular endothelial cell injury, formation of free radicals and oxidative stress appear to be involved in this association (46–48). In this study, we found an inverse correlation between plasma vitamin C and UA concentrations.

Nutrients such as vitamins E and C appear to ameliorate the inflammatory response after stroke. Administration of ascorbic acid has been shown to have beneficial vascular effects in type 2 diabetes (49). In a recent study, a significant association between low levels of antioxidant and poor early outcome in stroke patients was reported (50). The inflammatory response appears to play a key role in mediating poststroke brain damage and the patient’s prognosis (51). An interesting observation of this study was the improved plasma vitamin E levels at the end of the study by 53% in men and 33% in women compared with baseline (data not shown). Furthermore, a positive correlation between plasma levels of vitamin C and vitamin E in both men and women was also observed (r = 0.459, P = 0.024), suggesting an important interaction between these nutrients.

Several studies have demonstrated that CRP is a highly sensitive marker for cardiovascular disease in both men and women (23,52). In fact, consistent results from >15 well-conducted prospective studies in initially healthy persons have shown a strong and independent association between the circulating concentration of CRP and cardiovascular end points, including acute myocardial infarction, stroke and progression of peripheral arterial occlusive disease (53,54). An important observation of our research group in a previous study (55) was the inverse correlation between plasma vitamin E levels and levels of CRP in a healthy elderly population, which may explain in part the beneficial effects of vitamin E on the vascular system.

PGE₂ is one of the major prostaglandins produced during inflammation (56). A variety of PGE₂-mediated effects have been reported, including vascular smooth muscle tonus, glomerular cell function and neuronal activity (57). PGE₂ also modulates neurotransmitter release, sensitizes secretory fibers to noxious stimuli, and induces fever and sleep (58). PGE₂ increases significantly after cerebrovascular events and is positively associated with the severity and clinical outcome of stroke (59). In this study, a significant reduction in PGE₂ levels had occurred in men and women at the end of the intervention (Table 2). It is possible that this decrease in PGE₂ concentration was mediated in part by the improved vitamin E status because several studies have shown a significant association between vitamin E and PGE₂ levels.

The in vivo reduction in oxidative stress and inflammatory status observed in this study, associated with increased plasma vitamin C concentration from HP orange juice, provides new evidence of the health benefits of eating fruit. In fact, several studies have reported important vascular benefits, including improved endothelial cell function and lower blood pressure, associated with high vitamin C intake. Thus, a generous intake of orange juice may play a role in delaying chronic disease, including cognitive declines.

Some limitations of this study should be acknowledged. Perhaps the most important is the small number of subjects enrolled in the study. However, because of the relatively small variability in the various analyses (intra-assay and interassay) performed, we suggest that the small variability contributed to the clear differences observed among men and women in some of the variables measured before and after drinking the orange juice. Another limitation of the study is the lack of clinical outcomes associated with plasma levels of vitamin C after intake of HP orange juice. Because this was a healthy population, the main objective was to assess the bioavailability of vitamin C in the HP orange juice and its association with oxidative stress and inflammatory status.

In conclusion, drinking two glasses of HP orange juice (500 mL/d) containing 250 mg of vitamin C significantly increased plasma vitamin C concentration and reduced levels of 8-epiPGF₂, UA, CRP and PGE₂. Vitamin C was significantly and inversely correlated with 8-epiPGF₂. These findings suggest that higher levels of vitamin C in tissues can be achieved through drinking a generous amount of orange juice daily. Thus, evaluation of the health-promoting properties of vitamin C in fruits deserves further attention.

	ACKNOWLEDGMENTS

 
We would like to thank to Gerard Dallal, Chief of the Biostatistics Unit at HNRCA for his advice. We thank I. Blanco, C. Herrero, T. Motilla and P. Martinez, personnel at the Clínica Puerta de Hierro, Madrid, Spain, and all participants for their enthusiasm and contributions to the study.

	FOOTNOTES

 
¹ Supported in part by the Coordinated Project CAM 07G/0040/2000-CAM 07G/0041/2000 (Comunidad Autónoma de Madrid), the Project AGL2002–04059-C02–02 (Ministerio de Ciencia y Tecnología), Madrid, Spain (M.P.C.); and a Fulbright/MECD Award for Postdoctoral Research in the United States of America, Visiting Scholar Program, Commission for Cultural, Educational and Scientific Exchange between the United States of America and Spain (C.S.M.).

³ Abbreviations used: CRP, C-reactive protein; EIA, enzyme immunoassay; 8-epiPGF₂, 8-isoprostane; HP, high pressure; PGE₂, prostaglandin E₂; UA, uric acid.

Manuscript received 5 March 2003. Initial review completed 1 April 2003. Revision accepted 21 April 2003.

	LITERATURE CITED

TOP ABSTRACT SUBJECTS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 

1. Liu, S., Manson, J. E., Lee, I.-M., Cole, S. R., Hennekens, C. H., Willett, W. C. & Buring, J. E. (2000) Fruit and vegetable intake and risk of cardiovascular disease: the Women’s Health Study. Am. J. Clin. Nutr. 72:922-928.[Abstract/Free Full Text]

2. Martin, A., Cherubini, A., Andres-Lacueva, C., Paniagua, M. & Joseph, J. A. (2002) Effects of fruits and vegetables on levels of vitamins E and C in the brain and their association with cognitive performance. J. Nutr. Health Aging 6:392-404.[Medline]

3. Aviram, M., Dornfeld, L., Rosenblat, M., Volkova, N., Kaplan, M., Coleman, R., Hayek, T., Presser, D. & Fuhrman, B. (2000) Pomegranate juice consumption reduces oxidative stress, atherogenic modifications to LDL, and platelet aggregation: studies in humans and in atherosclerotic apolipoprotein E-deficient mice. Am. J. Clin. Nutr. 71:1062-1076.[Abstract/Free Full Text]

4. Young, J. F., Nielsen, S. E., Haraldsdottir, J., Daneshvar, B., Lauridsen, S. T., Knuthsen, P., Crozier, A., Sandstrom, B. & Dragsted, L. O. (1999) Effect of fruit juice intake on urinary quercetin excretion and biomarkers of antioxidative status. Am. J. Clin. Nutr. 69:87-94.[Abstract/Free Full Text]

5. Mermelstein, N. H. (1999) High-pressure pasteurization of juice. Food Technol. 53:86-90.

6. Hendrickx, M., Ludikhuyze, L., Van den Broeck, I. & Weemaes, C. (1998) Effects of high pressure on enzymes related to food quality. Trends Food Sci. Technol. 9:197-203.

7. Nienaber, U. & Shellhammer, T. H. (2001) High-pressure processing of orange juice: combination treatments and a shelf life study. J. Food Sci. 66:332-336.

8. Sánchez-Moreno, C., Plaza, L., De Ancos, B. & Cano, M. P. (2003) Vitamin C, pro-vitamin A carotenoids and other carotenoids in high-pressurized orange juice during refrigerated storage. J. Agric. Food Chem. 51:647-653.[Medline]

9. van Popel, G. & van den Berg, H. (1997) Vitamins and cancer. Cancer Lett. 114:195-202.[Medline]

10. Brigelius-Flohe, R., Kelly, F. J., Salonen, J. T., Neuzil, J., Zingg, J. M. & Azzi, A. (2002) The European perspective on vitamin E: current knowledge and future research. Am. J. Clin. Nutr. 76:703-716.[Abstract/Free Full Text]

11. Menniti, F. S., Knoth, J. & Diliberto, E. J., Jr (1986) Role of ascorbic acid in dopamine beta-hydroxylation. The endogenous enzyme cofactor and putative electron donor for cofactor regeneration. J. Biol. Chem. 261:16901-16908.[Abstract/Free Full Text]

12. Levine, M., Dhariwal, K. R., Welch, R. W., Wang, Y. & Park, J. B. (1995) Determination of optimal vitamin C requirements in humans. Am J. Clin. Nutr. 62:1347S-1356S.[Abstract/Free Full Text]

13. Simon, J. A. (1992) Vitamin C and cardiovascular disease: a review. J. Am. Coll. Nutr. 11:107-125.[Abstract]

14. Ness, A. R., Khaw, K. T., Bingham, S. & Day, N. E. (1996) Vitamin C status and serum lipids. Eur. J. Clin. Nutr. 50:724-729.[Medline]

15. Ness, A. R., Khaw, K. T., Bingham, S. & Day, N. E. (1996) Vitamin C status and respiratory function. Eur. J. Clin. Nutr. 50:573-579.[Medline]

16. Simon, J. A., Hudes, E. S. & Tice, J. A. (2001) Relation of serum ascorbic acid to mortality among US adults. J. Am Coll. Nutr. 20:255-263.[Abstract/Free Full Text]

17. Reilly, M. P., Delanty, N., Roy, L., Rokach, J., Callaghan, P. O., Crean, P., Lawson, J. A. & FitzGerald, G. A. (1997) Increased formation of the isoprostanes IPF2alpha-I and 8-epi-prostaglandin F2alpha in acute coronary angioplasty: evidence for oxidant stress during coronary reperfusion in humans. Circulation 96:3314-3320.[Abstract/Free Full Text]

18. Banerjee, M., Kang, K. H., Morrow, J. D., Roberts, L. J. & Newman, J. H. (1992) Effects of a novel prostaglandin, 8-epi-PGF2 alpha, in rabbit lung in situ. Am. J. Physiol. 263:H660-H663.

19. Morrow, J. D., Moore, K. P., Awad, J. A., Ravenscraft, M. D., Marini, G., Badr, K. F., Williams, R. & Roberts, L. J., 2nd (1993) Marked overproduction of non-cyclooxygenase derived prostanoids (F2-isoprostanes) in the hepatorenal syndrome. J. Lipid Mediat. 6:417-420.[Medline]

20. Vacchiano, C. A. & Tempel, G. E. (1994) Role of nonenzymatically generated prostanoid, 8-iso-PGF₂, in pulmonary oxygen toxicity. J. Appl. Physiol. 77:2912-2917.[Abstract/Free Full Text]

21. Pratico, D., Basili, S., Vieri, M., Cordova, C., Violi, F. & Fitzgerald, G. A. (1998) Chronic obstructive pulmonary disease is associated with an increase in urinary levels of isoprostane F2alpha-III, an index of oxidant stress. Am. J. Respir. Crit. Care Med. 158:1709-1714.[Abstract/Free Full Text]

22. Bickel, C., Rupprecht, H. J., Blankenberg, S., Rippin, G., Hafner, G., Daunhauer, A., Hofmann, K. P. & Meyer, J. (2002) Serum uric acid as an independent predictor of mortality in patients with angiographically proven coronary artery disease. Am. J. Cardiol. 89:12-17.[Medline]

23. Ridker, P. M., Hennekens, C. H., Buring, J. E. & Rifai, N. (2000) C-reactive protein and other markers of inflammation in the prediction of cardiovascular disease in women. N. Engl. J. Med. 342:836-843.[Abstract/Free Full Text]

24. Beharka, A., Redican, S., Leka, L. & Meydani, S. N. (1997) Vitamin E status and immune function. Methods Enzymol. 282:247-263.[Medline]

25. Cunniff, P. (1995) Official Methods of Analysis of AOAC International 1995 AOAC International Arlington, VA.

26. Sánchez-Moreno, C., Plaza, L., De Ancos, B. & Cano, M. P. (2003) Effect of high-pressure processing on health-promoting attributes of freshly squeezed orange juice (Citrus sinensis L.) during chilled storage. Eur. Food Res. Technol. 216:18-22.

27. Martin, A. & Frei, B. (1997) Both intracellular and extracellular vitamin C inhibit atherogenic modification of LDL by human vascular endothelial cells. Arterioscler. Thromb. Vasc. Biol. 17:1583-1590.[Abstract/Free Full Text]

28. Pradelles, P., Grassi, J. & Maclouf, J. (1985) Enzyme immunoassays of eicosanoids using acetylcholine esterase as label: an alternative to radioimmunoassay. Anal. Chem. 57:1170-1173.[Medline]

29. Wilkins, J., Gallimore, J. R., Moore, E. G. & Pepys, M. B. (1998) Rapid automated high sensitivity enzyme immunoassay of C-reactive protein. Clin. Chem. 44:1358-1361.[Free Full Text]

30. Christman, J. W., Abdolrasulnia, R., Shepherd, V. L. & Rinaldo, J. E. (1991) Paradoxical regulation by PGE-2 on release of neutrophil chemoattractants by rat bone marrow macrophages. Prostaglandins 41:251-262.[Medline]

31. Sánchez-Moreno, C., Cano, M. P., De Ancos, B., Plaza, L., Olmedilla, B., Granado, F. & Martín, A. (2003) Effect of orange juice intake on vitamin C levels and biomarkers of antioxidative status in humans. Am. J. Clin. Nutr. (in press).

32. Erlund, I., Meririnne, E., Alfthan, G. & Aro, A. (2001) Plasma kinetics and urinary excretion of the flavanones naringenin and hesperetin in humans after ingestion of orange juice and grapefruit juice. J. Nutr. 131:235-241.[Abstract/Free Full Text]

33. Broekmans, W. M., Klopping-Ketelaars, I. A., Schuurman, C. R., Verhagen, H., van den Berg, H., Kok, F. J. & van Poppel, G. (2000) Fruits and vegetables increase plasma carotenoids and vitamins and decrease homocysteine in humans. J. Nutr. 130:1578-1583.[Abstract/Free Full Text]

34. Valero, M. P., Fletcher, A. E., De Stavola, B. L., Vioque, J. & Alepuz, V. C. (2002) Vitamin C is associated with reduced risk of cataract in a Mediterranean population. J. Nutr. 132:1299-1306.[Abstract/Free Full Text]

35. Diliberto, E. J., Jr, Dean, G., Carter, C. & Allen, P. L. (1982) Tissue, subcellular, and submitochondrial distributions of semidehydroascorbate reductase: possible role of semidehydroascorbate reductase in cofactor regeneration. J. Neurochem. 39:563-568.[Medline]

36. Gokce, N., Keaney, J. F., Frei, B., Holbrook, M., Olesiak, M., Zachariah, B. J., Leeuwenburgh, C., Heinecke, J. W. & Vita, J. A. (1999) Long-term ascorbic acid administration reverses endothelial vasomotor dysfunction in patients with coronary artery disease. Circulation 99:3234-3240.[Abstract/Free Full Text]

37. Ammerman, A. S., Lindquist, C. H., Lohr, K. N. & Hersey, J. (2002) The efficacy of behavioral interventions to modify dietary fat and fruit and vegetable intake: a review of the evidence. Prev. Med. 35:25-41.[Medline]

38. Meister, A. (1994) Glutathione-ascorbic acid antioxidant system in animals. J. Biol. Chem. 269:9397-9400.[Free Full Text]

39. Morrow, J. D., Hill, K. E., Burk, R. F., Nammour, T. M., Badr, K. F. & Roberts, L. J., 2nd (1990) A series of prostaglandin F2-like compounds are produced in vivo in humans by a non-cyclooxygenase, free radical-catalyzed mechanism. Proc. Natl. Acad. Sci. U.S.A. 87:9383-9387.[Abstract/Free Full Text]

40. Huang, H. Y., Appel, L. J., Croft, K. D., Miller, E. R., 3rd, Mori, T. A. & Puddey, I. B. (2002) Effects of vitamin C and vitamin E on in vivo lipid peroxidation: results of a randomized controlled trial. Am. J. Clin. Nutr. 76:549-555.[Abstract/Free Full Text]

41. Audoly, L. P., Rocca, B., Fabre, J. E., Koller, B. H., Thomas, D., Loeb, A. L., Coffman, T. M. & FitzGerald, G. A. (2000) Cardiovascular responses to the isoprostanes iPF₂-III and iPE₂-III are mediated via the thromboxane A₂ receptor in vivo. Circulation 101:2833-2840.[Abstract/Free Full Text]

42. Cracowski, J. L., Tremel, F., Marpeau, C., Baguet, J. P., Stanke-Labesque, F., Mallion, J. M. & Bessard, G. (2000) Increased formation of F(2)-isoprostanes in patients with severe heart failure. Heart 84:439-440.[Free Full Text]

43. Reilly, M., Delanty, N., Lawson, J. A. & FitzGerald, G. A. (1996) Modulation of oxidant stress in vivo in chronic cigarette smokers. Circulation 94:19-25.[Abstract/Free Full Text]

44. Patrignani, P., Panara, M. R., Tacconelli, S., Seta, F., Bucciarelli, T., Ciabattoni, G., Alessandrini, P., Mezzetti, A., Santini, G., Sciulli, M. G., Cipollone, F., Davi, G., Gallina, P., Bon, G. B. & Patrono, C. (2000) Effects of vitamin E supplementation on F2-isoprostane and thromboxane biosynthesis in healthy cigarette smokers. Circulation 102:539-545.[Abstract/Free Full Text]

45. Meisinger, C., Thorand, B., Schneider, A., Stieber, J., Doring, A. & Lowel, H. (2002) Sex differences in risk factors for incident type 2 diabetes mellitus: the MONICA Augsburg cohort study. Arch. Intern. Med. 162:82-89.[Abstract/Free Full Text]

46. Vasquez-Vivar, J., Santos, A. M., Junqueira, V. B. & Augusto, O. (1996) Peroxynitrite mediated formation of free radicals in human plasma: EPR detection of ascorbyl, albumin-thiyl and uric-derived free radicals. Biochem. J. 314:869-876.

47. Leyva, F., Anker, S., Swan, J. W., Godsland, I. F., Wingrove, C. S., Chua, T. P., Stevenson, J. C. & Coats, A. J. (1997) Serum uric acid as an index of impaired oxidative metabolism in chronic heart failure. Eur. Heart J. 18:858-865.[Abstract/Free Full Text]

48. Anker, S. D., Leyva, F., Poole-Wilson, P. A., Kox, W. J., Stevenson, J. C. & Coats, A. J. (1997) Relation between serum uric acid and lower limb blood flow in patients with chronic heart failure. Heart 78:39-43.[Abstract/Free Full Text]

49. Mullan, B. A., Young, I. S., Fee, H. & McCance, D. R. (2002) Ascorbic acid reduces blood pressure and arterial stiffness in type 2 diabetes. Hypertension 40:804-809.[Abstract/Free Full Text]

50. Cherubini, A., Polidori, M. C., Bregnocchi, M., Pezzuto, S., Cecchetti, R., Ingegni, T., di Iorio, A., Senin, U. & Mecocci, P. (2000) Antioxidant profile and early outcome in stroke patients. Stroke 31:2295-2300.[Abstract/Free Full Text]

51. Lavine, S. D., Hofman, F. M. & Zlokovic, B. V. (1998) Circulating antibody against tumor necrosis factor-alpha protects rat brain from reperfusion injury. J. Cereb. Blood Flow Metab. 18:52-58.[Medline]

52. Winbeck, K., Kukla, C., Poppert, H., Klingelhofer, J., Conrad, B. & Sander, D. (2002) Elevated C-reactive protein is associated with an increased intima to media thickness of the common carotid artery. Cerebrovasc. Dis. 13:57-63.[Medline]

53. Koenig, W., Sund, M., Frohlich, M., Fischer, H. G., Lowel, H., Doring, A., Hutchinson, W. L. & Pepys, M. B. (1999) C-Reactive protein, a sensitive marker of inflammation, predicts future risk of coronary heart disease in initially healthy middle-aged men: results from the MONICA (Monitoring Trends and Determinants in Cardiovascular Disease) Augsburg Cohort Study, 1984 to 1992. Circulation 99:237-242.[Abstract/Free Full Text]

54. Danesh, J. & Pepys, M. B. (2000) C-reactive protein in healthy and in sick populations. Eur. Heart J. 21:1564-1565.[Free Full Text]

55. Sánchez-Moreno, C., Dashe, J., Scott, T., Thaler, D., Folstein, M. F. & Martin, A. (2003) Nutritional changes and inflammatory response associated with stroke influencing cognitive outcome. Stroke (in press).

56. Boje, K. M., Jaworowicz, D., Jr & Raybon, J. J. (2003) Neuroinflammatory role of prostaglandins during experimental meningitis: evidence suggestive of an in vivo relationship between nitric oxide and prostaglandins. J. Pharmacol. Exp. Ther. 304:319-325.[Abstract/Free Full Text]

57. Dormond, O., Bezzi, M., Mariotti, A. & Ruegg, C. (2002) Prostaglandin E2 promotes integrin alpha Vbeta 3-dependent endothelial cell adhesion, rac-activation, and spreading through cAMP/PKA-dependent signaling. J. Biol. Chem. 277:45838-45846.[Abstract/Free Full Text]

58. Chen, C., Magee, J. C. & Bazan, N. G. (2002) Cyclooxygenase-2 regulates prostaglandin E2 signaling in hippocampal long-term synaptic plasticity. J. Neurophysiol. 87:2851-2857.[Abstract/Free Full Text]

59. Fagan, S. C., Castellani, D. & Gengo, F. M. (1986) Prostanoid concentrations in human CSF following acute ischaemic brain infarction. Clin. Exp. Pharmacol. Physiol. 13:629-632.[Medline]

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