Fernando Granados

Orange juice, a rich source of vitamin C, accounts for 60% of all fruit juices and juice-based drinks consumed in western Europe. Orange juice preservation is currently accomplished by traditional pasteurization. Pulsed electric fields (PEF) have been studied as a nonthermal food preservation method. Food technology needs in the area of processing are driven by nutrition. Therefore, the objectives of this study were to assess the bioavailability of vitamin C from pulsed electric fields-treated orange juice in comparison with freshly squeezed orange juice and its impact on 8-epiPGF(2alpha) concentrations (biomarker of lipid peroxidation) in a healthy human population. Six subjects consumed 500 mL/day of pulsed electric fields-treated orange juice and six subjects consumed 500 mL/day of freshly squeezed orange juice for 14 days, corresponding to an intake of about 185 mg/day of ascorbic acid. On the first day of the study, subjects drank the juice in one dose, and on days 2-14 they consumed 250 mL in the morning and 250 mL in the afternoon. Blood was collected every hour for 6 hours on the first day and again on days 7 and 14. In the dose-response study, the maximum increase in plasma vitamin C occurred 4 hours postdose. Vitamin C remained significantly higher on days 7 and 14 in both orange juice groups. Plasma 8-epiPGF(2alpha) concentrations was lower at the end of the study (P < 0.001) in both groups. Plasma levels of vitamin C and 8-epiPGF(2alpha) were inversely correlated. Pulsed electric fields-preservation of orange juice retains the vitamin C bioavailability and antioxidant properties of fresh juice with a longer shelf-life.

Type-1 diabetics have been considered to be at risk for increased oxidative stress which has been implicated in the development of long-term diabetes complications. Evidence suggests that antioxidant activity may be an important mechanism by which carotenoids could confer protection in human health. Our aim was to compare the serum carotenoid depletion rate in type-1 diabetics and control subjects consuming low-carotenoid diets. Ten type-1 diabetics and 8 controls followed a very low-carotenoid diet for 21 days. Dietary intake was recorded daily and fasting blood samples collected at baseline and after 1, 2, 3, 6, 11, 15, 16, 17, and 21 days. Individual carotenoids in serum were analyzed by a validated HPLC method. In both groups, carotenoid intake was less than 5% of the season-adjusted carotenoid reference intake. These diets resulted in decreased serum carotenoid levels in both groups, although depletion curves, final mean concentrations and the estimated half-life of carotenoids in serum revealed no differences between type-1 diabetics and controls. Levels of other minor serum carotenoids, cis-isomers and keto-carotenoids, also decreased whereas serum retinol and alpha- and gamma-tocopherol did not change during the study. Upon a low-carotenoid intake, the depletion rate of carotenoids in serum in young type-1 diabetics does not differ from that observed in matched related controls.

Consumption of fruits and vegetables is associated with a reduced risk of death from all causes including heart disease and stroke. In this work, the bioavailability of vitamin C from a Mediterranean vegetable soup (gazpacho) constituted mainly of tomato, pepper and cucumber, and its influence on plasma vitamin C, 8-epi-prostaglandin F(2alpha) (8-epi-PGF2alpha), prostaglandin E2 (PGE2), monocyte chemotactic protein-1 (MCP-1), and the cytokines/tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-6 concentrations in a healthy human population were assessed. Six men and six women consumed 500 ml of commercial gazpacho per day for 14 days, corresponding to an intake of 78 mg of ascorbic acid per day. There were no differences (P = .22) in baseline plasma vitamin C concentrations between the men and women. The maximum increase (P < .05) in plasma vitamin C occurred 4 h postdose in both men and women. Vitamin C concentrations were significantly higher (P < .03) on Days 7 and 14 of the intervention. Baseline concentrations of uric acid and 8-epi-PGF2alpha were significantly higher (P < or = .032) in men than in women. Baseline concentrations of 8-epi-PGF2alpha decreased significantly (P < or = .05) by Day 14 of the intervention. A significant inverse correlation was observed between vitamin C and 8-epi-PGF2alpha (r = -.415, P = .049). Baseline concentrations of PGF2 and MCP-1 were significantly higher (P< or = .025) in men than in women but decreased significantly (P< or = .05) by Day 14 of the intervention. No effect on TNF-alpha, IL-1beta and IL-6 was observed at Day 14 of the intervention. Drinking gazpacho (500 ml/day) significantly increases plasma concentrations of vitamin C and significantly decreases 8-epi-PGF2alpha, PGE2 and MCP-1 concentrations in healthy humans.

Carotenoids are thought to act as antioxidants in vivo, decreasing oxidative damage to biomolecules and thus protecting against coronary heart disease and cancer. However, human intervention studies with beta-carotene have given equivocal results in terms of cancer incidence. In an alternative molecular epidemiological approach, we have employed the 'comet assay' (single cell alkaline gel electrophoresis) to measure strand breaks, oxidized pyrimidines and altered purines in the DNA of lymphocytes from volunteers supplemented with alpha/beta-carotene, lutein, lycopene or placebo. In addition, we measured concentrations of the main serum carotenoids, and vitamins E and C, by HPLC. We report a significant negative correlation between basal concentrations of total serum carotenoids and oxidized pyrimidines. A similar correlation was seen between individual carotenoids (notably lutein and beta-carotene) and oxidized pyrimidines. However, carotenoid supplementation did not have a significant effect on endogenous oxidative damage. This suggests that there are some factors in the basal diet, probably found in fruit and vegetables, that decrease oxidative damage to DNA. In this case, basal serum carotenoids may simply be markers of consumption of fruit and vegetables, they themselves having little or no protective value.

... Fernando Granado, Begoiia Olmedilla,' Inmaculada Blanco, and Enrique Rojas-Hidalgo ... Carotene and lutein were found to be present in all of the vegetables analyzed except the sweet red pepper, which contains zeaxanthin but not lutein. ...

Background Lutein, a non-provitamin A carotenoid, is frequently consumed in the human diet. It is distributed preferentially in certain human tissues (i. e., retina) and shows a high antioxidant activity. Type 1 diabetic patients have been considered to be at risk of increased oxidative stress that may contribute to accelerated atherogenesis and to the microangiopathic complications of the disease. Aim of the study To assess the influence of type 1 diabetes mellitus on the serum depletion rate and bioavailability of lutein. Subjects and Methods Ten type 1 diabetics and eight controls consumed a low carotenoid diet for 21 days and the bioavailability study was performed in 7 diabetics and 5 controls on day 15 with the administration of a capsule of lutein esters from marigold extract. Samples were collected at baseline and on days 1, 2, 3, 6, 11, 15 (eight times during 9 h), 16, 17 and 21. Lutein and other carotenoids were determined by HPLC in triglyceride-rich lipoprotein (TRL) fractions and plasma or serum. Results Serum depletion curve, area of concentrations under time curve (AUC) and final concentration percentages were similar in diabetics and controls. In the bioavailability study, all-trans-lutein increased in both groups and AUC, maxima concentrations in TRL and serum and time required for maxima concentration in serum were similar in diabetics and controls. Conclusions These data suggest that in the group of patients assessed, type 1 diabetes mellitus does not apparently influence the absorption and depletion rate of lutein in serum.

The bioavailability of vitamin C from pulsed electric fields (PEF)-treated vegetable soup in comparison with freshly made (FM) vegetable soup-gazpacho-and its impact on 8-epiPGF(2alpha) and uric acid concentrations in a human population were assessed. For this purpose six subjects consumed 500 ml PEF-treated vegetable soup/day, and six subjects consumed 500 ml FM vegetable soup/day for 14 days. On the first day of the study, the subjects drank the vegetable soup in one dose (dose-response study), and on days 2-14 they consumed 250 ml in the morning and 250 ml in the afternoon (multiple-dose-response study). Blood was collected every hour for 6 h on the first day and again on days 7 and 14. All blood samples were analyzed for vitamin C, 8-epiPGF(2alpha), and uric acid. The maximum increase in plasma vitamin C occurred 3 h post-dose in both the PEF and the FM groups. Vitamin C remained significantly higher (P = 0.05) on days 7 and 14. The plasma 8-epiPGF(2alpha) concentration was significantly lower at the end of the study in both the PEF group (P = 0.002) and the FM group (P = 0.05). Plasma levels of vitamin C and 8-epiPGF(2alpha) were inversely correlated in both groups (r= -0.549, P = 0.018; and r = -0.743, P = 0.0004, respectively). To summarize, drinking two servings (500 ml) of PEF-treated or FM gazpacho daily increases plasma vitamin C and significantly decreases 8-epiPGF(2alpha) concentrations in healthy humans.