Daily consumption of a high-phenol extra-virgin olive oil reduces oxidative DNA damage in postmenopausal women

Extra-virgin olive oils (EVOO), high in phenolic compounds with antioxidant properties, could be partly responsible for the lower mortality and incidence of cancer and CVD in the Mediterranean region. The present study aims to measure oxidative DNA damage in healthy human subjects consuming olive oils with different concentrations of natural phenols. A randomised cross-over trial of high-phenol EVOO (high-EVOO; 592 mg total phenols/kg) v. low-phenol EVOO (low-EVOO; 147 mg/kg) was conducted in ten postmenopausal women in Florence. Subjects were asked to substitute all types of fat and oils habitually consumed with the study oil (50 g/d) for 8 weeks in each period. Oxidative DNA damage was measured by the comet assay in peripheral blood lymphocytes, collected at each visit during the study period. Urine samples over 24 h were collected to measure the excretion of the olive oil phenols. The average of the four measurements of oxidative DNA damage during treatment with high-EVOO was 30 % lower than the average during the low-EVOO treatment (P=0.02). Urinary excretion of hydroxytyrosol and its metabolite homovanillyl alcohol were significantly increased in subjects consuming high-EVOO. Despite the small sample size, the present study showed a reduction of DNA damage by consumption of an EVOO rich in phenols, particularly hydroxytyrosol.     

Dietary energy density and body weight changes after 3 years in the PREDIMED study

The association of dietary energy density (ED) and overweight is not clear in the literature. Our aim was to study in 4259 of the PREDIMED trial whether an increase in dietary ED based on a higher adherence to a Mediterranean dietary pattern was associated with 3-year weight gain.

A validated 137-item food-frequency questionnaire was administered. Multivariable-adjusted models were used to analyze the association between 3-year ED change and the subsequent 3-year body weight change.

The most important weight reduction after 3-year follow-up was observed in the two lowest quintiles and the highest quintile of ED change. The highest ED increase was characterized by an increased intake of extra virgin olive oil (EVOO) and nuts and a decreased intake of other oils, vegetable and fruit consumption (p?In conclusion, increased 3-year ED in the PREDIMED study, associated with a higher EVOO and nuts consumption, was not associated with weight gain.     

Effects of differing phenolic content in dietary olive oils on lipids and LDL oxidation

Summary.Background: Evidence from in vitro studies suggests that antioxidant olive oil phenolic compounds can prevent LDL oxidation. However, in vivo evidence in support of this hypothesis is sparse.Aim of the study: to establish the antioxidant effect of olive oils with differences in their phenolic compounds content in humansMethods: A controlled, double blind, cross-over, randomized, clinical trial using three similar olive oils with increasing phenolic concentration (from 0 to 150 mg/Kg) was conducted in 30 healthy volunteers. Olive oils were administered over three periods of 3 weeks preceded by two-week washout periods.Results: Urinary tyrosol and hydroxytyrosol increased (p < 0.020), in vivo plasma oxidized LDL decreased (p = 0.006), and ex vivo resistance of LDL to oxidation increased (p = 0.012) with the phenolic content of the olive oil administered. After virgin olive oil administration, an increase (p = 0.029) was observed in HDL cholesterol levels.Conclusions: Sustained consumption of virgin olive oil with the high phenolic content was more effective in protecting LDL from oxidation and in rising HDL cholesterol levels than that of other type of olive oils. Dose-dependent changes in oxidative stress markers, and phenolic compounds in urine, were observed with the phenolic content of the olive oil administered. Our results support the hypothesis that virgin olive oil consumption could provide benefits in the prevention of oxidative processes.* Participants of the SOLOS-Investigation are listed in the Appendix.     

Extra-Virgin Olive Oil Enhances the Blood–Brain Barrier Function in Mild Cognitive Impairment: A Randomized Controlled Trial

Mild cognitive impairment (MCI) and early Alzheimer’s disease (AD) are characterized by blood–brain barrier (BBB) breakdown leading to abnormal BBB permeability ahead of brain atrophy or dementia. Previous findings in AD mouse models have reported the beneficial effect of extra-virgin olive oil (EVOO) against AD, which improved BBB and memory functions and reduced brain amyloid-β (Aβ) and related pathology. This work aimed to translate these preclinical findings to humans in individuals with MCI. We examined the effect of daily consumption of refined olive oil (ROO) and EVOO for 6 months in MCI subjects on BBB permeability (assessed by contrast-enhanced MRI), and brain function (assessed using functional-MRI) as the primary outcomes. Cognitive function and AD blood biomarkers were also assessed as the secondary outcomes. Twenty-six participants with MCI were randomized with 25 participants completed the study. EVOO significantly improved clinical dementia rating (CDR) and behavioral scores. EVOO also reduced BBB permeability and enhanced functional connectivity. While ROO consumption did not alter BBB permeability or brain connectivity, it improved CDR scores and increased functional brain activation to a memory task in cortical regions involved in perception and cognition. Moreover, EVOO and ROO significantly reduced blood Aβ₄₂/Aβ₄₀ and p-tau/t-tau ratios, suggesting that both altered the processing and clearance of Aβ. In conclusion, EVOO and ROO improved CDR and behavioral scores; only EVOO enhanced brain connectivity and reduced BBB permeability, suggesting EVOO biophenols contributed to such an effect. This proof-of-concept study justifies further clinical trials to assess olive oil’s protective effects against AD and its potential role in preventing MCI conversion to AD and related dementias.     

Olive oil reduces oxidative damage in a 3-nitropropionic acid-induced Huntington's disease-like rat model

Abstract

Free radicals contribute to altered neuronal functions in neurodegenerative diseases and brain aging, by producing lipid- and other molecule-dependent modifications. The Mediterranean diet has been associated with a reduced risk of neurodegenerative disease. This study sought to verify whether extra-virgin olive oil (EVOO) exerted a brain antioxidant effect, protecting the brain against the oxidative stress caused by 3-nitropropionic acid (3NP). 3NP was administered intraperitoneally (i.p.) at a dose of 20 mg/kg body weight over four consecutive days. EVOO (representing 10% of calorie intake in the total standard daily diet of rats) and hydroxytyrosol (HT; 2.5 mg/kg body weight) were administered for 14 days. In all studied samples, 3NP caused a rise in lipid peroxides (LPO) and a reduction in glutathione (GSH) content. While the results showed that EVOO and HT reduces lipid peroxidation product levels and blocks the GSH depletion prompted by 3NP in both striatum and rest of the brain in Wistar rats. In addition, EVOO blocks and reverses the effect of 3NP on succinate dehydrogenase activity. In brief, the data obtained indicate that EVOO and HT act as a powerful brain antioxidant.     

Minor compounds of olive oil have postprandial anti-inflammatory effects

High postprandial levels of TAG may further induce endothelial dysfunction and inflammation in subjects with high fasting levels of TAG, an effect that seems to be related to oxidative stress. The present study investigated whether minor compounds of olive oil with antioxidant activity decrease postprandial levels of soluble isoforms of intercellular adhesion molecule 1 (sICAM-1) and vascular cell adhesion molecule 1 (sVCAM-1), as surrogate markers of vascular inflammation, after a high-fat meal. A randomized crossover and blind trial on fourteen healthy and fourteen hypertriacylglycerolaemic subjects was performed. The study involved a 1-week adaptation lead-in period on a National Cholesterol Education Program Step I diet supplemented with extra-virgin olive oil (EVOO) containing 1125 mg polyphenols/kg and 350 mg tocopherols/kg, or refined olive oil (ROO) with no polyphenols or tocopherols. After a 12 h fast, the participants ate a high-fat meal enriched in EVOO or ROO (50 g/m2 body surface area), which on average provided 3700 kJ energy with a macronutrient profile of 72% fat, 22% carbohydrate and 6% protein. Blood samples drawn hourly over the following 8 h demonstrated a similar postprandial TAG response for both EVOO and ROO meals. However, in both healthy and hypertriacylglycerolaemic subjects the net incremental area under the curve for sICAM-1 and sVCAM-1 were significantly lower after the EVOO meal. In conclusion,the consumption of EVOO with a high content of minor antioxidant compounds may have postprandial anti-inflammatory protective effects.     

Growth Hormone (GH) Treatment in Non-GH Deficient Chronic Disease

Objective: This trial evaluated the effect of antioxidant supplementation on the urinary excretion of 11-dehydro TXB₂/2,3 dinor 6 keto PGF_1α ratio, a marker of the pathogenesis of thrombosis and arteriosclerosis.

Methods: This study was a randomised, double-blind, placebo-controlled trial involving 186 presumably healthy volunteers. One hundred received a multi-antioxidant supplementation and 86 a placebo for two years. Blood zinc, selenium, beta-carotene, vitamin C and E and urinary excretion of 11-dehydro TXB₂ and 2,3 dinor 6 keto PGF_1α were measured.

Results: Baseline subject characteristics did not differ between the two groups. Blood zinc, selenium, and beta-carotene concentrations significantly increased between baseline and two years in the multi-antioxidant supplementation group supporting subject compliance (p < 0.05). At two years, the median urinary 11-dehydro TXB₂/2,3 dinor 6 keto PGF_1α ratio was significantly lower in the multi-antioxidant supplementation group (3.4 versus 2.78, p = 0.015). Serum selenium concentration was the only antioxidant studied that was significantly related to the urinary 11-dehydro TXB₂/2,3 dinor 6 keto PGF_1α ratio.

Conclusions: These results support the hypothesis that a low-dose multi-antioxidant supplementation may contributes to a reduction in platelet activation which is beneficial for cardiovascular function.     

Bioavailability and antioxidant effects of olive oil phenols in humans: a review

OBJECTIVE: We reviewed the bioavailability and antioxidant effects of phenols from extra virgin olive oil. SEARCH STRATEGY: We searched the MEDLINE database for the years 1966-2002. To review the bioavailability of olive oil phenols, we selected animal and human studies that studied the absorption, metabolism, and urinary excretion of olive oil phenols. We also estimated the intake of the various phenols in the Mediterranean area. To review the antioxidant effects of olive oil phenols, we included human and animal studies on the effect of olive oil phenols on markers of oxidative processes in the body. We excluded studies without a proper control treatment and studies in which the antioxidant effects of phenols could not be disentangled from those of the fatty acid composition of olive oil. RESULTS: Bioavailability studies in humans show that the absorption of olive oil phenols is probably larger than 55-66 mol%, and that at least 5% is excreted in urine as tyrosol and hydroxytyrosol. Animal studies suggest that phenol-rich olive oil lowers oxidisability of ex vivo low-density lipoprotein (LDL) particles or lowers markers in urine of oxidative processes in the body. In five out of seven human studies, however, these effects of phenols were not found. There are no data on the phenol concentrations in plasma that are attainable by intake of olive oil. We estimated that 50 g of olive oil per day provides about 2 mg or approximately 13 micromol of hydroxytyrosol-equivalents per day, and that the plasma concentration of olive oil phenols with antioxidant potential resulting from such an intake can be at most 0.06 micromol/l. This is much lower than the minimum concentrations of these phenols (50-100 micromol) required to show antioxidant activity in vitro. CONCLUSION: Although phenols from olive oil seem to be well absorbed, the content of olive oil phenols with antioxidant potential in the Mediterranean diet is probably too low to produce a measurable effect on LDL oxidisability or other oxidation markers in humans. The available evidence does not suggest that consumption of phenols in the amounts provided by dietary olive oil will protect LDL against oxidative modification to any important extent.     

Hypolipidimic and antioxidant activities of virgin olive oil and its fractions in 2,4-diclorophenoxyacetic acid-treated rats

Objective

We examined the effects of extra virgin olive oil (EVOO) and its hydrophilic and lipophilic fractions on serum lipids, oxidative stress, and morphologic and functional liver damages induced by 2,4-diclorophenoxyacetic acid (2,4-D).

Methods

Male Wistar rats were divided randomly into eight groups: control; 2,4-D at a dose of 5 mg/kg of body weight (2,4-D); 2,4-D plus EVOO (2,4-D/EVOO); 2,4-D plus the hydrophilic fraction (2,4-D/OOHF); 2,4-D plus the lipophilic fraction (2,4-D/OOLF); only EVOO (EVOO); only the hydrophilic fraction (OOHF); and only the lipophilic fraction (OOLF). These components were administered daily by gavage for 4 wk.

Results

A hepatic architecture aberration, increased activities of aspartate and alanine aminotransferase enzymes, total and low-density lipoprotein cholesterol, and malondialdehyde (MDA) level, and a decreased antioxidant defense system were observed in the 2,4-D group. The administration of EVOO restored the damage caused by 2,4-D by a significant decrease of plasma total and low-density lipoprotein levels and a moderate increase of high-density lipoprotein cholesterol. The 2,4-D/OOHF group exhibited a pronounced enhancement of the antioxidant defense system by an increase of superoxide dismutase, catalase, and glutathione peroxidase levels and a decrease of plasma and liver MDA levels. However, less improvement in the liver histoarchitecture and antioxidant status was observed in rats supplemented with OOLF diet, despite its richness in α-tocopherol.

Conclusion

Extra virgin olive oil may be a potential functional food source of antioxidants than can decrease the frequency of cardiovascular diseases and liver damage.     

Olive oil reduces oxidative damage in a 3-nitropropionic acid-induced Huntington's disease-like rat model

Free radicals contribute to altered neuronal functions in neurodegenerative diseases and brain aging, by producing lipid- and other molecule-dependent modifications. The Mediterranean diet has been associated with a reduced risk of neurodegenerative disease. This study sought to verify whether extra-virgin olive oil (EVOO) exerted a brain antioxidant effect, protecting the brain against the oxidative stress caused by 3-nitropropionic acid (3NP). 3NP was administered intraperitoneally (i.p.) at a dose of 20 mg/kg body weight over four consecutive days. EVOO (representing 10% of calorie intake in the total standard daily diet of rats) and hydroxytyrosol (HT; 2.5 mg/kg body weight) were administered for 14 days. In all studied samples, 3NP caused a rise in lipid peroxides (LPO) and a reduction in glutathione (GSH) content. While the results showed that EVOO and HT reduces lipid peroxidation product levels and blocks the GSH depletion prompted by 3NP in both striatum and rest of the brain in Wistar rats. In addition, EVOO blocks and reverses the effect of 3NP on succinate dehydrogenase activity. In brief, the data obtained indicate that EVOO and HT act as a powerful brain antioxidant.     

In Vitro Effects of Extracts of Extra Virgin Olive Oil on Human Colon Cancer Cells

The Mediterranean diet is associated with a lower incidence of atherosclerosis, cardiovascular diseases, and some types of cancer. Recent interest has been focused on the biological activity of phenolic compounds present in extra virgin olive oils (EVOOs). Both in vivo and in vitro studies have shown that EVOO components have positive effects on metabolic parameters, such as plasma lipoproteins, oxidative damage, inflammatory markers, platelet function, and antimicrobial activity. We have investigated the possible interactions between 2 extracts of extra virgin olive oil and estrogen receptor β (ERβ) in an in vitro model of colon cancer. The qualification and quantification of the components of the 2 samples tested showed that phenolic compounds—hydroxytyrosol, secoiridoids, and lignans—are the major represented compounds. EVOO extracts were tested on a colon cancer cell line engineered to overexpress ERβ (HCT8-β8). By using custom made Oligo microarray, gene expression profiles of colon cancer cells challenged with EVOO-T extracts when compared with those of cells exposed to 17β-estradiol (17β-E2). This study demonstrated that the EVOO extracts tested showed an antiproliferative effect on colon cancer cells through the interaction with estrogen-dependent signals involved in tumor cell growth. Specifically, the ability of EVOO extracts to inhibit cell proliferation was superimposable to the activation of the ERβ receptor, similar to what was observed after 17β-E2 challenge.     

Influence of extra virgin olive oil diet enriched with hydroxytyrosol in a chronic DSS colitis model

Purpose

Recent epidemiological studies have shown that habitual consumption of extra virgin olive oil (EVOO), the characteristic culinary fat of the Mediterranean area, is effective in the prevention of diverse types of digestive disorders such as inflammatory bowel disease. Many of these benefits are, in addition to its high proportion of oleic acid, due to the high content of phenolic compounds.

Methods

Six-week-old mice were randomized into three dietary groups: standard, EVOO and hydroxytyrosol-enriched EVOO. After 30?days, mice that were exposed to 3% DSS for 5?days developed acute colitis that progressed to severe chronic inflammation during a regime of 21?days of water.

Results

Diets enriched with EVOO significantly attenuated the clinical and histological signs of damage, improving results from disease activity index and reducing about 50% the mortality caused by DSS. Moreover, hydroxytyrosol supplement showed better results. Cytokines study showed that TNF-α was maintained near to sham control and IL-10 levels were significantly improved in EVOO and EVOO plus hydroxytyrosol diet-DSS groups. In the same way, COX-2 and iNOS were downregulated, and the activation of p38 MAPK was reduced. We also observed a higher significant reduction in iNOS in hydroxytyrosol-enriched EVOO compared with EVOO alone.

Conclusions

EVOO diets exerted a noteworthy beneficial effect in chronic DSS-induced colitis by cytokine modulation and COX-2 and iNOS reduction via downregulation of p38 MAPK. In addition to the beneficial effect by EVOO, supplementation of the diet with hydroxytyrosol may improve chronic colitis through iNOS downregulation plus its antioxidant capacity.     

Phenolic compounds and antioxidant activity of Italian extra virgin olive oil Monti Iblei

The profile of phenolic compounds, antioxidant capacity, oxidative stability, and chemical characteristics (free acidity, peroxide value, specific extinction K232 and K270 values, and DeltaK) of 22 commercial extra virgin olive oil (EVOO) samples coming from the denomination of protected origin (DPO) Monti Iblei and obtained from olives harvested in the period September-December 2005 in the production area of the province of Siracusa (Sicily, Italy) were evaluated. The content of total phenols, expressed as gallic acid equivalents, ranged from 14.80 to 121.20 mg/100 g, with a mean value of 53.72 mg/100 g, mainly attributable to deacetoxyligstroside aglycone, deacetoxyoleuropein aglycone, oleuropein aglycone, and ligstroside aglycone. The mean values of Trolox equivalent antioxidant capacity (TEAC) and of oxidative stability were 54.76 and 11.99 hours, respectively. Both TEAC and oxidative stability were positively correlated to the phenol content and to the percentage of inclusion of the olive cultivar "Tonda Iblea." The high mean content of phenols, besides conferring prolonged oxidative stability, likely confers to the DPO Monti Iblei EVOO marked potential beneficial effects for human health.     

Administration of minor polar compound-enriched extra virgin olive oil decreases platelet aggregation and the plasma concentration of reduced homocysteine in rats

We investigated the effect of extra virgin olive oil (EVOO) on platelet aggregation and plasma concentrations of homocysteine (Hcy) redox forms in rats in relation to the minor polar compound (MPC) concentration of EVOO. We used 3 olive oil samples with similar fatty acid but different MPC concentrations: refined olive oil (RF) with traces of MPC (control oil), native EVOO with low MPC concentration (LC), and EVOO with high MPC concentration (HC) enriching LC with its own MPC. Oil samples were administered to rats by gavage (1.25 mL/kg body weight) using 2 experimental designs: acute (24-h food deprivation and killed 1 h after EVOO administration) and subacute (12-d treatment, a daily dose of oil for 12 d, and killed after 24 h of food deprivation). Platelet aggregation was induced by ADP (ex vivo tests) and a reduction in platelet reactivity occurred in cells from rats given LC in the subacute study and in cells from rats administered HC in both studies as indicated by an increase in the agonist half maximal effective concentration. HC inhibited platelet aggregation induced by low ADP doses (reversible aggregation) in cells of rats in both the acute and subacute studies, whereas LC had this effect only in the subacute experiment. Moreover, in rats administered HC in both experiments, the plasma concentration of free reduced Hcy (rHcy) was lower and Hcy bound to protein by disulfide bonds (bHcy) was greater than in RF-treated rats. bHcy was also greater in rats given LC than in RF-treated rats in the subacute experiment. Plasma free-oxidized Hcy was greater in rats given LC and HC than in those administered RF only in the subacute experiment. In conclusion, these results show that MPC in EVOO inhibit platelet aggregation and reduce the plasma rHcy concentration, effects that may be associated with cardiovascular protection.     

Characterization of Buriti (Mauritia flexuosa) Pulp Oil and the Effect of Its Supplementation in an In Vivo Experimental Model

Mauritia flexuosa (Buriti) pulp oil contains bioactive substances and lipids that are protective against cardiovascular and inflammatory diseases. We performed physical and chemical analyses to verify its quality and stability. Buriti oil was stable according to the Rancimat test, presenting an induction period of 6.6 h. We evaluated the effect of supplementation with crude buriti oil and olive oil on metabolic parameters in 108 Swiss mice for 90 days. We investigated six groups: extra virgin olive oil (EVOO) 1 and 2 (1000 and 2000 mg/kg), buriti oil (BO) 1 and 2 (1000 and 2000 mg/kg), synergic (S) (BO1 + EVOO1), and control (water dose 1000 mg/kg). The animals were euthanized to examine their blood, livers, and fats. The supplementation did not interfere with food consumption, weight gain, and histological alterations in the liver. Group S showed the strongest relationship with the fractions HDL-c and non-HDL-c, indicating a possible cardioprotective effect. Moreover, we observed significantly higher IL-6 levels in the control, EVOO2, and BO1 groups than in the EVOO1 group. Resistin was also significantly higher for the synergic treatment than for the control. We conclude that BO combined with EVOO could be an excellent food supplement for human consumption.     

Bioavailability of phenols from a phenol-enriched olive oil

Phenolic compounds are one of the main reasons behind the healthy properties of virgin olive oil (VOO). However, their daily intake from VOO is low compared with that obtained from other phenolic sources. Therefore, the intake of VOO enriched with its own phenolic compounds could be of interest to increase the daily dose of these beneficial compounds. To evaluate the effectiveness of enrichment on their bioavailability, the concentration of phenolic compounds and their metabolites in human plasma (0, 60, 120, 240 and 300 min) from thirteen healthy volunteers (seven men and six women, aged 25 and 69 years) was determined after the ingestion of a single dose (30 ml) of either enriched virgin olive oil (EVOO) (961·17 mg/kg oil) or control VOO (288·89 mg/kg oil) in a cross-over study. Compared with VOO, EVOO increased plasma concentration of the phenol metabolites, particularly hydroxytyrosol sulphate and vanillin sulphate (P < 0·05). After the consumption of VOO, the maximum concentration of these peaks was reached at 60 min, while EVOO shifted this maximum to 120 min. Despite these differences, the wide variability of results indicates that the absorption and metabolism of olive oil phenols are highly dependent on the individual.     

Correlation between Olive Oil Intake and Gut Microbiota in Colorectal Cancer Prevention

Extra virgin olive oil (EVOO) is a mainstay of the Mediterranean diet with its excellent balance of fats and antioxidant bioactive compounds. Both the phenolic and lipid fractions of EVOO contain a variety of antioxidant and anticancer substances which might protect from the development of colorectal cancer (CRC). The function of the intestinal microbiome is essential for the integrity of the intestinal epithelium, being protective against pathogens and maintaining immunity. Indeed, dysbiosis of the microbiota alters the physiological functions of the organ, leading to the onset of different diseases including CRC. It is known that some factors, including diet, could deeply influence and modulate the colon microenvironment. Although coming from animal models, there is increasing evidence that a diet rich in EVOO is linked to a significant reduction in the diversity of gut microbiome (GM), causing a switch from predominant bacteria to a more protective group of bacteria. The potential beneficial effect of the EVOO compounds in the carcinogenesis of CRC is only partially known and further trials are needed in order to clarify this issue. With this narrative review, we aim at discussing the available evidence on the effect of olive oil consumption on GM in the prevention of CRC.     

Oxidative stress, diet, and the etiology of preeclampsia

BACKGROUND: A current theory holds that oxidative stress, ie, an imbalance between maternal prooxidants and antioxidants, is a component of preeclampsia. It is uncertain whether such an imbalance occurs before clinical recognition of the syndrome or whether it is related to diet. OBJECTIVE: We measured urinary excretion of the isoprostane 8-iso-prostaglandin F(2alpha), which is an indicator of oxidative damage to lipids, and the total antioxidant power, which is a global measure of antioxidant status, at the entry to prenatal care. We also examined the relation of these indexes to diet during pregnancy. DESIGN: A cohort of 307 gravidae from Camden, NJ, was studied from entry to prenatal care (at 15.0 +/- 0.49 wk gestation). Measures of the maternal diet were obtained by 24-h recall. RESULTS: Risk of preeclampsia was increased 5-fold with higher urinary isoprostane excretion and decreased 3-fold with higher total antioxidant power. Over the course of pregnancy, there were significant trends for an association of higher isoprostane excretion with increased consumption of energy-adjusted fat, polyunsaturated fat, and polyunsaturated fatty acids (n-3, n-6, and linoleic and linolenic fatty acids), whereas total antioxidant power was not related to diet. CONCLUSIONS: Increased urinary excretion of isoprostane and decreased antioxidant production is an imbalance that is consistent with oxidative stress, and it precedes clinical recognition of preeclampsia. The maternal diet is an underlying factor that provides an environment for free radical generation.     

Association of mate tea (Ilex paraguariensis) intake and dietary intervention and effects on oxidative stress biomarkers of dyslipidemic subjects

ObjectiveTo evaluate the effect of long-term ingestion of mate tea, with or without dietary intervention, on the markers of oxidative stress in dyslipidemic individuals.MethodsSeventy-four dyslipidemic volunteers participated in this randomized clinical trial. Subjects were divided into three treatment groups: mate tea (MT), dietary intervention (DI), and mate tea with dietary intervention (MD). Biochemical and dietary variables were assessed at the beginning of the study (baseline) and after 20, 40, 60, and 90 d of treatment. Participants in the MT and MD groups consumed 1 L/d of mate tea. Those in the DI and MD groups were instructed to increase their intake of fruit, legumes and vegetables and decrease their consumption of foods rich in cholesterol and saturated and trans-fatty acids. Biomarkers of oxidative stress such as antioxidant capacity of serum (ferric reducing antioxidant potential assay), uric acid, reduced glutathione, paraoxonase-1 enzyme, lipid hydroperoxide (LOOH), and protein carbonyl were analyzed.ResultsParticipants in the DI group showed a significant decrease in total fat and saturated fatty acid intakes. Those in the DI and MD groups presented a significant increase in vitamin C consumption. For all groups, there was a significant increase in ferric reducing antioxidant potential and reduced glutathione concentrations but no significant changes in LOOH, protein carbonyl, and paraoxonase-1 values. The reduced glutathione concentration was positively correlated with the consumption of monounsaturated fatty acids, fiber, and vitamin C, whereas levels of LOOH were inversely correlated with intakes of vitamin C and fiber. In addition, LOOH correlated positively with low-density lipoprotein cholesterol and inversely with high-density lipoprotein cholesterol, which had a positive association with paraoxonase-1.ConclusionThe ingestion of mate tea independently of the dietary intervention increased plasma and blood antioxidant protection in patients with dyslipidemia.     

Effect of phenol-rich extra virgin olive oil on markers of oxidation in healthy volunteers

OBJECTIVE: We studied whether consumption of phenol-rich extra virgin olive oil affects the susceptibility of low density lipoproteins (LDL) to oxidation and other markers of oxidation in humans. DESIGN: Randomized cross-over intervention trial, stratified according to sex, age and energy intake. SETTING: Division of Human Nutrition and Epidemiology, Wageningen University, The Netherlands. SUBJECTS: Forty-six healthy men and women completed the study. INTERVENTION: Subjects consumed two diets supplying 69 g per day of extra virgin olive oil either rich or poor in phenols for 3 weeks each. The mean difference in phenol intake between the treatments was 18 mg per day. Vitamin E intake was low during the whole study. Fasting blood samples were taken twice at the end of each period. RESULTS: Resistance of LDL and high density lipoprotein (HDL) to oxidation was not affected by treatment. The mean lag time of copper-induced formation of conjugated dienes was 1.6 min shorter in LDL and 0.4 min longer in HDL after the high phenol diet. Other markers of antioxidant capacity in plasma were also not affected: mean lipid hydroperoxides were 0.07 micromol/l higher, mean malondialdehydes were 0.001 micromol/l higher, mean protein carbonyls were 0.001 nmol/mg protein lower, and the mean ferric reducing ability of plasma (FRAP) was 0.006 mmol/l higher after the high phenol diet. All 95% confidence intervals enclosed zero. Serum cholesterol concentrations were not affected by the treatment. CONCLUSION: Consumption of 18 mg per day of phenols from extra virgin olive oil for 3 weeks did not affect LDL or HDL oxidation or other markers of antioxidant capacity in fasting plasma samples.