Phenol-Enriched Virgin Olive Oil Promotes Macrophage-Specific Reverse Cholesterol Transport In Vivo.

The intake of olive oil (OO) enriched with phenolic compounds (PCs) promotes ex vivo HDL-mediated macrophage cholesterol efflux in humans. We aimed to determine the effects of PC-enriched virgin OO on reverse cholesterol transport (RevCT) from macrophages to feces in vivo. Female C57BL/6 mice were given intragastric doses of refined OO (ROO) and a functional unrefined virgin OO enriched with its own PC (FVOO) for 14 days. Our experiments included two independent groups of mice that received intragastric doses of the phenolic extract (PE) used to prepare the FVOO and the vehicle solution (saline), as control, for 14 days. FVOO intake led to a significant increase in serum HDL cholesterol and its ability to induce macrophage cholesterol efflux in vitro when compared with ROO group. This was concomitant with the enhanced macrophage-derived [3H]cholesterol transport to feces in vivo. PE intake per se also increased HDL cholesterol levels and significantly promoted in vivo macrophage-to-feces RevCT rate when compared with saline group. PE upregulated the expression of the main macrophage transporter involved in macrophage cholesterol efflux, the ATP binding cassettea1. Our data provide direct evidence of the crucial role of OO PCs in the induction of macrophage-specific RevCT in vivo.

Reference ranges of glycated hemoglobin (HbA1c) in capillary blood in the Spanish population.

Cross-sectional analysis describing HbA1c reference values by sex and age in a randomly selected Mediterranean general population sample. Using two methods, Point-of-Care systems and centralized laboratory, results show that HbA1c values increase with age. Almost half of the sample aged 65 years or older had median values >5.7% (prediabetes cut-off point).

A Functional Virgin Olive Oil Enriched with Olive Oil and Thyme Phenolic Compounds Improves the Expression of Cholesterol Efflux-Related Genes: A Randomized, Crossover, Controlled Trial.

The consumption of antioxidant-rich foods such as virgin olive oil (VOO) promotes high-density lipoprotein (HDL) anti-atherogenic capacities. Intake of functional VOOs (enriched with olive/thyme phenolic compounds (PCs)) also improves HDL functions, but the gene expression changes behind these benefits are not fully understood. Our aim was to determine whether these functional VOOs could enhance the expression of cholesterol efflux-related genes. In a randomized, double-blind, crossover, controlled trial, 22 hypercholesterolemic subjects ingested for three weeks 25 mL/day of: (1) a functional VOO enriched with olive oil PCs (500 mg/kg); (2) a functional VOO enriched with olive oil (250 mg/kg) and thyme PCs (250 mg/kg; FVOOT), and; (3) a natural VOO (olive oil PCs: 80 mg/kg, control intervention). We assessed whether these interventions improved the expression of cholesterol efflux-related genes in peripheral blood mononuclear cells by quantitative reverse-transcription polymerase chain reactions. The FVOOT intervention upregulated the expression of CYP27A1 (P = 0.041 and P = 0.053, versus baseline and the control intervention, respectively), CAV1 (P = 0.070, versus the control intervention), and LXRß, RXRα, and PPARß/δ (P = 0.005, P = 0.005, and P = 0.038, respectively, relative to the baseline). The consumption of a functional VOO enriched with olive oil and thyme PCs enhanced the expression of key cholesterol efflux regulators, such as CYP27A1 and nuclear receptor-related genes.

Prediction of coronary disease incidence by biomarkers of inflammation, oxidation, and metabolism.

The effect of circulating biomarkers in predicting coronary artery disease (CAD) is not fully elucidated. This study aimed to determine the relationship with CAD and the predictive capacity of nine biomarkers of inflammation (TNF-α, IL-10, IL-6, MCP-1, CRP), oxidation (GHS-Px), and metabolism (adiponectin, leptin, and insulin). This was a case-cohort study, within the REGICOR population-cohorts (North-Eastern Spain), of 105 CAD cases and 638 individuals randomly selected from a cohort of 5,404 participants aged 35-74 years (mean follow-up = 6.1 years). Biomarkers' hazard ratio (HR)/standard deviation was estimated with Cox models adjusted for age, sex, and classical risk factors. Discrimination improvement and reclassification were analyzed with the c-index and the Net reclassification index (NRI). GHS-Px (adjusted HRs = 0.77; 95%CI:0.60-0.99), insulin (1.46; 1.08-1.98), leptin (1.40; 1.03-1.90), IL-6 (1.34; 1.03-1.74), and TNF-α (1.80; 1.26-2.57) were significantly associated with CAD incidence. In the model adjusted for all biomarkers, TNF-α (1.87;1.31-2.66) and insulin (1.59;1.16-2.19) were independently associated with CAD. This final model, compared to a model without biomarkers, showed a c-index difference of 1.3% (-0.7, 3.2) and a continuous NRI of 33.7% (2.6, 61.9). TNF-α and insulin are independently associated with CAD incidence and they improve reclassification when added to a model including classical risk factors.

Phenol-enriched olive oils improve HDL antioxidant content in hypercholesterolemic subjects. A randomized, double-blind, cross-over, controlled trial.

At present, high-density lipoprotein (HDL) function is thought to be more relevant than HDL cholesterol quantity. Consumption of olive oil phenolic compounds (PCs) has beneficial effects on HDL-related markers. Enriched food with complementary antioxidants could be a suitable option to obtain additional protective effects. Our aim was to ascertain whether virgin olive oils (VOOs) enriched with (a) their own PC (FVOO) and (b) their own PC plus complementary ones from thyme (FVOOT) could improve HDL status and function. Thirty-three hypercholesterolemic individuals ingested (25 ml/day, 3 weeks) (a) VOO (80 ppm), (b) FVOO (500 ppm) and (c) FVOOT (500 ppm) in a randomized, double-blind, controlled, crossover trial. A rise in HDL antioxidant compounds was observed after both functional olive oil interventions. Nevertheless, α-tocopherol, the main HDL antioxidant, was only augmented after FVOOT versus its baseline. In conclusion, long-term consumption of phenol-enriched olive oils induced a better HDL antioxidant content, the complementary phenol-enriched olive oil being the one which increased the main HDL antioxidant, α-tocopherol. Complementary phenol-enriched olive oil could be a useful dietary tool for improving HDL richness in antioxidants.

Effect of olive oil phenolic compounds on the expression of blood pressure-related genes in healthy individuals.

PURPOSE: To investigate whether the ingestion of olive oil having different phenolic contents influences the expression of blood pressure-related genes, involved in the renin-angiotensin-aldosterone system, in healthy humans. METHODS: A randomized, double-blind, crossover human trial with 18 healthy subjects, who ingested 25 mL/day of olive oils (1) high (366 mg/kg, HPC) and (2) low (2.7 mg/kg, LPC) in phenolic compounds for 3 weeks, preceded by 2-week washout periods. Determination of selected blood pressure-related gene expression in peripheral blood mononuclear cells (PBMNC) by qPCR, blood pressure and systemic biomarkers. RESULTS: HPC decreased systolic blood pressure compared to pre-intervention values and to LPC, and maintained diastolic blood pressure values compared to LPC. HPC decreased ACE and NR1H2 gene expressions compared with pre-intervention values, and IL8RA gene expression compared with LPC. CONCLUSIONS: The introduction to the diet of an extra-virgin olive oil rich in phenolic compounds modulates the expression of some of the genes related to the renin-angiotensin-aldosterone system. These changes could underlie the decrease in systolic blood pressure observed.

Olive Oil Polyphenols Decrease LDL Concentrations and LDL Atherogenicity in Men in a Randomized Controlled Trial.

BACKGROUND: Olive oil polyphenols have shown protective effects on cardiovascular risk factors. Their consumption decreased oxidative stress biomarkers and improved some features of the lipid profile. However, their effects on LDL concentrations in plasma and LDL atherogenicity have not yet been elucidated. OBJECTIVE: Our objective was to assess whether the consumption of olive oil polyphenols could decrease LDL concentrations [measured as apolipoprotein B-100 (apo B-100) concentrations and the total number of LDL particles] and atherogenicity (the number of small LDL particles and LDL oxidizability) in humans. METHODS: The study was a randomized, cross-over controlled trial in 25 healthy European men, aged 20-59 y, in the context of the EUROLIVE (Effect of Olive Oil Consumption on Oxidative Damage in European Populations) study. Volunteers ingested 25 mL/d raw low-polyphenol-content olive oil (LPCOO; 366 mg/kg) or high-polyphenol-content olive oil (HPCOO; 2.7 mg/kg) for 3 wk. Interventions were preceded by 2-wk washout periods. Effects of olive oil polyphenols on plasma LDL concentrations and atherogenicity were determined in the sample of 25 men. Effects on lipoprotein lipase (LPL) gene expression were assessed in another sample of 18 men from the EUROLIVE study. RESULTS: Plasma apo B-100 concentrations and the number of total and small LDL particles decreased (mean ± SD: by 5.94% ± 16.6%, 11.9% ± 12.0%, and 15.3% ± 35.1%, respectively) from baseline after the HPCOO intervention. These changes differed significantly from those after the LPCOO intervention, which resulted in significant increases of 6.39% ± 16.6%, 4.73% ± 22.0%, and 13.6% ± 36.4% from baseline (P < 0.03). LDL oxidation lag time increased by 5.0% ± 10.3% from baseline after the HPCOO intervention, which was significantly different only relative to preintervention values (P = 0.038). LPL gene expression tended to increase by 26% from baseline after the HPCOO intervention (P = 0.08) and did not change after the LPCOO intervention. CONCLUSION: The consumption of olive oil polyphenols decreased plasma LDL concentrations and LDL atherogenicity in healthy young men. This trial was registered at www.controlled-trials.com as ISRCTN09220811.

Complementary phenol-enriched olive oil improves HDL characteristics in hypercholesterolemic subjects. A randomized, double-blind, crossover, controlled trial. The VOHF study.

SCOPE: Consumption of olive oil (OO) phenolic compounds (PCs) has beneficial effects on lipid profile. HDL functionality is currently considered to be a more important issue than its circulating quantity. Our aim was to assess whether functional virgin olive oils (FVOOs), one enriched with its own PC (500 ppm; FVOO) and another with OOPC (250 ppm) plus additional complementary PCs from thyme (250 ppm) (total: 500 ppm; FVOOT (functional virgin olive oil with thyme)), could improve HDL functionality related properties versus a virgin OO control (80 ppm; VOO). METHODS AND RESULTS: In a randomized, double-blind, crossover, controlled trial, 33 hypercholesterolemic volunteers received 25 mL/day of VOO, FVOO, and FVOOT during 3 wk. HDL cholesterol increased 5.74% (p < 0.05) versus its baseline after the FVOOT consumption in the participants without hypolipidemic medication. We detected, after FVOOT consumption, an increase in HDL2 -subclass (34.45, SD = 6.38) versus VOO intake (32.73, SD = 6.71). An increment in esterified cholesterol/free cholesterol and phospholipids/free cholesterol in HDL was observed after FVOOT consumption (1.73, SD = 0.56; 5.44, SD = 1.39) compared with VOO intervention (1.53, SD = 0.35; 4.97, SD = 0.81) and FVOO intervention (1.50, SD = 0.33; 4.97, SD = 0.81). Accordingly, lecithin-cholesterol acyltransferase mass increased after FVOOT consumption (1228 µg/mL, SD = 130), compared with VOO consumption (1160 µg/mL, SD = 144). An improvement in HDL oxidative-status was reflected after FVOOT consumption versus its baseline, given an increment in the paraoxonase activity (118 × 10(3) U/L, SD = 24). CONCLUSION: FVOOT improves HDL-subclass distribution and composition, and metabolism/antioxidant enzyme activities. FVOOT could be a useful dietary tool in the management of high cardiovascular risk patients.

Anti-inflammatory effect of white wine in CKD patients and healthy volunteers.

BACKGROUND: Mediterranean-style diet has been considered for its important beneficial effects on the progression of CV disease. Wine is an important component of the Mediterranean diet, and moderate wine drinkers have lower mortality rates than nondrinkers and heavy drinkers in epidemiologic studies. The beneficial effects of red wine are thought to be dependent on the polyphenol compounds such as resveratrol that exhibit potent antioxidant activity. However, white wine, although lacking polyphenols, contains simple phenols, such as tyrosol (Tyr) and hydroxytyrosol (OH-Tyr), characteristic also of extra-virgin olive oil, which may share similar antioxidant and inflammatory properties. PATIENTS AND METHODS: The effect of white wine and extra-virgin olive oil on inflammatory markers was evaluated in 10 healthy volunteers and in 10 patients with CKD (chronic kidney disease) K-DOQI stage III-IV in a prospective, single blind, randomized, cross-over trial. After two weeks of wash-out from alcoholic beverages, subjects were randomized to a cross-over design A-B or B-A of a 2-week treatment with white wine (4 ml/kg body weight, 0.48 g/kg of alcohol 12%, corresponding to 2-3 glasses/daily) and extra-virgin olive oil (treatment A) or extra-virgin olive oil alone (treatment B). The two study periods were separated by a two-week wash-out period. At baseline and at the end of each treatment, plasma levels of inflammatory markers C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and interleukin-8 (IL-8) concentration were determined. Urinary levels of Tyr, OH-Tyr, and their metabolites were measured at the same time. RESULTS: During combined consumption of white wine and extra-virgin olive oil (treatment A), plasma levels of CRP and IL-6 decreased from 4.1 ± 1.8 to 2.4 ± 1.9 mg/l (p < 0.05) and from 5.3 ± 3.2 to 3.4 ± 2.3 mg/l (p < 0.05) in CKD patients. CRP decreased from 2.6 ± 1.2 to 1.9 ± 0.9 mg/l (p < 0.05), and IL-6 decreased from 2.2 ± 1.8 to 1.7 ± 1.3 mg/l (p = ns) in healthy volunteers. No significant variation versus baseline was observed during treatment B. A significant increase in urinary Tyr and OH-Tyr was observed during treatment A (white wine and extra-virgin olive oil). CONCLUSIONS: Plasma markers of chronic inflammation were significantly reduced in CKD patients during the combined consumption of white wine and olive oil, suggesting a possible anti-inflammatory effect of this nutritional intervention.

Olive oil polyphenols enhance high-density lipoprotein function in humans: a randomized controlled trial.

OBJECTIVE: Olive oil polyphenols have shown beneficial properties against cardiovascular risk factors. Their consumption has been associated with higher cholesterol content in high-density lipoproteins (HDL). However, data on polyphenol effects on HDL quality are scarce. We, therefore, assessed whether polyphenol-rich olive oil consumption could enhance the HDL main function, its cholesterol efflux capacity, and some of its quality-related properties, such HDL polyphenol content, size, and composition. APPROACH AND RESULTS: A randomized, crossover, controlled trial with 47 healthy European male volunteers was performed. Participants ingested 25 mL/d of polyphenol-poor (2.7 mg/kg) or polyphenol-rich (366 mg/kg) raw olive oil in 3-week intervention periods, preceded by 2-week washout periods. HDL cholesterol efflux capacity significantly improved after polyphenol-rich intervention versus the polyphenol-poor one (+3.05% and -2.34%, respectively; P=0.042). Incorporation of olive oil polyphenol biological metabolites to HDL, as well as large HDL (HDL2) levels, was higher after the polyphenol-rich olive oil intervention, compared with the polyphenol-poor one. Small HDL (HDL3) levels decreased, the HDL core became triglyceride-poor, and HDL fluidity increased after the polyphenol-rich intervention. CONCLUSIONS: Olive oil polyphenols promote the main HDL antiatherogenic function, its cholesterol efflux capacity. These polyphenols increased HDL size, promoted a greater HDL stability reflected as a triglyceride-poor core, and enhanced the HDL oxidative status, through an increase in the olive oil polyphenol metabolites content in the lipoprotein. Our results provide for the first time a first-level evidence of an enhancement in HDL function by polyphenol-rich olive oil.

Oxidized low-density lipoprotein antibodies in myocardial infarction patients without classical risk factors.

AIM: To determine whether circulating antibodies against oxidized low-density lipoprotein (LDL; OLAB) levels are associated with acute myocardial infarction (AMI) in individuals without classical cardiovascular risk factors. METHODS: A case-control study including 34 first AMI patients without classical risk factors (smoking, dyslipidemia, hypertension or diabetes) and 45 population-based healthy controls. RESULTS: There were no differences in anthropometric variables between cases and controls. Oxidized LDL levels were similar in both groups. Total cholesterol, LDL cholesterol, apolipoprotein B and physical activity were lower in cases than in controls. OLAB levels were also lower in cases than controls (128 versus 447 U/l, P < 0.001). After adjusting for age, oxidized LDL and physical activity, participants with OLAB levels of 165 U/l or less had a higher risk of AMI (odds ratio, OR = 7.48, 95% confidence interval: 1.57-35.66). When the model was fitted with OLAB as a continuous variable, the natural logarithm (LnOLAB) levels were independently associated with AMI with an OR of 0.40 (95% confidence interval: 0.19-0.86). After adjusting the model by Framingham-risk-adapted score and oxidized LDL, the LnOLAB levels maintained their independent association (OR of 0.43, 95% confidence interval: 0.23-0.79). CONCLUSION: First AMI patients without classical risk factors had lower levels of OLAB compared with healthy controls. It is likely that the immunological reaction due to oxidized LDL participates as a preventive factor in the physiopathology of atherosclerosis.

Protection of LDL from oxidation by olive oil polyphenols is associated with a downregulation of CD40-ligand expression and its downstream products in vivo in humans.

BACKGROUND: Recently, the European Food Safety Authority approved a claim concerning the benefits of olive oil polyphenols for the protection of LDL from oxidation. Polyphenols could exert health benefits not only by scavenging free radicals but also by modulating gene expression. OBJECTIVE: We assessed whether olive oil polyphenols could modulate the human in vivo expressions of atherosclerosis-related genes in which LDL oxidation is involved. DESIGN: In a randomized, crossover, controlled trial, 18 healthy European volunteers daily received 25 mL olive oil with a low polyphenol content (LPC: 2.7 mg/kg) or a high polyphenol content (HPC: 366 mg/kg) in intervention periods of 3 wk separated by 2-wk washout periods. RESULTS: Systemic LDL oxidation and monocyte chemoattractant protein 1 and the expression of proatherogenic genes in peripheral blood mononuclear cells [ie, CD40 ligand (CD40L), IL-23α subunit p19 (IL23A), adrenergic ß-2 receptor (ADRB2), oxidized LDL (lectin-like) receptor 1 (OLR1), and IL-8 receptor-α (IL8RA)] decreased after the HPC intervention compared with after the LPC intervention. Random-effects linear regression analyses showed 1) a significant decrease in CD40, ADRB2, and IL8RA gene expression with the decrease of LDL oxidation and 2) a significant decrease in intercellular adhesion molecule 1 and OLR1 gene expression with increasing concentrations of tyrosol and hydroxytyrosol in urine. CONCLUSIONS: In addition to reducing LDL oxidation, the intake of polyphenol-rich olive oil reduces CD40L gene expression, its downstream products, and related genes involved in atherogenic and inflammatory processes in vivo in humans. These findings provide evidence that polyphenol-rich olive oil can act through molecular mechanisms to provide cardiovascular health benefits. This trial was registered at www.controlled-trials.com as ISRCTN09220811.

Unsaturated fatty alcohol derivatives of olive oil phenolic compounds with potential low-density lipoprotein (LDL) antioxidant and antiobesity properties.

A new route for the synthesis of fatty alcohol derivatives of hydroxytyrosol and other olive oil phenolic compounds was developed to allow the preparation of unsaturated derivatives. The biological activity of synthesized compounds was evaluated. Most of the compounds presented a significant antioxidant activity on low-density lipoprotein (LDL) particles. The activity of the tested products was significantly influenced by the number and position of unsaturations as well as modifications on the polar head of the synthesized compounds. Some of them presented modulation of food intake in rats and, due to their molecular similarity with CB(1) endogenous ligands, the endocannabinoid system and PPAR-α were also evaluated as potential targets. The pharmacodynamics could not be totally explained by CB(1) and PPAR-α receptor interactions because only two of the four compounds with biological activity showed a CB(1) activity and all of them presented low PPAR-α affinity, not justifying its whole in vivo activity. The hydroxytyrosol linoleylether (7) increased LDL resistance to oxidation with a capacity similar to that of hydroxytyrosol and was the most active in vivo compound with a hypophagic effect comparable to that of oleoylethanolamine. We consider that this compound could be a good lead compound for future drug development in obesity treatments.

Antioxidant activities of hydroxytyrosol main metabolites do not contribute to beneficial health effects after olive oil ingestion.

Hydroxytyrosol (HOTYR) and tyrosol (TYR), main phenolic compounds of olive oil, have been reported to contribute to the prevention of cardiovascular diseases due to their antioxidant activities, e.g., protection of low-density lipoprotein (LDL) oxidation. Their bioavailability in humans is poor, and they are found in biological fluids mainly as conjugated metabolites. Low concentrations of free phenols are unlikely to explain the biological activities seen in humans after olive oil intake. In this context, antioxidant activities of conjugated metabolites, in a range of concentrations compatible with their dietary consumption, were evaluated. Concentrations of metabolites and their core compounds were estimated in an intervention study of 11 healthy volunteers whose diet was supplemented with 50 ml of virgin olive oil, using high-performance liquid chromatography coupled to mass spectrometry for the simultaneous analysis of 3'-O- and 4'-O-HOTYR-glucuronides and 4'-O-glucuronides of TYR and homovanillyl alcohol in human urine. Glucuronides and core compounds were tested for their chemical (hydrogen donation by 1,1-diphenyl-2-picrylhydrazyl free radical test) and in vitro biological (inhibition of Cu-mediated LDL oxidation) antioxidant activities at the concentration ranges observed in human biological fluids (range, 0.01-10 muM) after dietary olive oil consumption. None of the glucuronides displayed significant antioxidant activities at the concentrations tested.

In vivo nutrigenomic effects of virgin olive oil polyphenols within the frame of the Mediterranean diet: a randomized controlled trial.

The aim of the study was to assess whether benefits associated with the traditional Mediterranean diet (TMD) and virgin olive oil (VOO) consumption could be mediated through changes in the expression of atherosclerosis-related genes. A randomized, parallel, controlled clinical trial in healthy volunteers (n=90) aged 20 to 50 yr was performed. Three-month intervention groups were as follows: 1) TMD with VOO (TMD+VOO), 2) TMD with washed virgin olive oil (TMD+WOO), and 3) control with participants' habitual diet. WOO was similar to VOO, but with a lower polyphenol content (55 vs. 328 mg/kg, respectively). TMD consumption decreased plasma oxidative and inflammatory status and the gene expression related with both inflammation [INF-gamma (INFgamma), Rho GTPase-activating protein15 (ARHGAP15), and interleukin-7 receptor (IL7R)] and oxidative stress [adrenergic beta(2)-receptor (ADRB2) and polymerase (DNA-directed) kappa (POLK)] in peripheral blood mononuclear cells. All effects, with the exception of the decrease in POLK expression, were particularly observed when VOO, rich in polyphenols, was present in the TMD dietary pattern. Our results indicate a significant role of olive oil polyphenols in the down-regulation of proatherogenic genes in the context of a TMD. In addition, the benefits associated with a TMD and olive oil polyphenol consumption on cardiovascular risk can be mediated through nutrigenomic effects.

Time course of changes in the expression of insulin sensitivity-related genes after an acute load of virgin olive oil.

Our aim was to examine whether an acute fat load could induce changes in the expression of insulin sensitivity-related genes in human peripheral blood mononuclear cells. Selection of candidate genes was based on previous studies with sustained virgin olive oil (VOO) consumption and biological plausibility in relation to insulin sensitivity. Eleven healthy volunteers ingested raw VOO (50 mL). Blood samples were collected at 0, 1 and 6 h. Plasma glucose, insulin and hydroxytyrosol increased at 1 h and decreased at 6 h. Lipid oxidative damage increased at 6 h (p < 0.05). Gene expression changes were characterized based on quantification of the samples relative to a reference sample [i.e., relative quantification (RQ) method]. A 1 h downregulation was observed in O-linked-N-acetylglucosamine transferase (OGT, RQ: 0.62 +/- 0.32) and arachidonate-5-lipoxygenase-activating protein (ALOX5AP, RQ: 0.64 +/- 0.31) genes (p < 0.005). OGT was upregulated at 6 h (RQ: 1.88 +/- 0.28, p < 0.05). CD36 (thrombospondin receptor) was upregulated at 1 h (RQ: 1.6 +/- 0.8, p < 0.05) returning to the basal values at 6 h. Lipoic acid synthetase (LIAS), peroxisome proliferator-activated receptor binding protein (PPARBP), a disintegrin and metallopeptidase domain 17 (ADAM17), and adrenergic beta-2-receptor (ADRB2) genes were upregulated at 6 h (range for the mean RQ: 1.33-1.56) following an increasing linear trend (p < 0.05) from baseline to 6 h. ALOX5AP and OGT genes inversely correlated with insulin and glucose levels at 1 h. ADAM17 and ADRB2 inversely correlated with oxLDL at 6 h (p < 0.05). Taken together, these observations may inform the future clinical nutrigenomics study designs and indicate that a single dose of VOO can elicit quantifiable and rapid changes in gene expression in targets that are mechanistically relevant for insulin sensitivity and the metabolic syndrome.

Presence of virgin olive oil phenolic metabolites in human low density lipoprotein fraction: determination by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry.

The biological benefits of olive oil in preventing the oxidation of low density lipoprotein (LDL) would seem to be linked to its high monounsaturated fatty acid contents, but also to its respective phenolic compounds contents. One prerequisite to assess the in vivo physiological significance of phenolic compounds is to determine their presence in human LDL following the ingestion of virgin olive oil. In this work, olive oil phenolic metabolites were identified using high-performance liquid chromatography in tandem with electrospray mass spectrometry (HPLC-ESI-MS/MS) detection, after solid phase extraction (SPE). Quantitative methods were developed in carrying out linearity, precision, sensitivity and recovery tests. The results from two methods of LDL separation were compared and shorter LDL isolation procedure showed a better recovery for antioxidants compounds in LDL. The metabolites identified in LDL were: hydroxytyrosol monoglucuronide, hydroxytyrosol monosulfate, tyrosol glucuronide, tyrosol sulfate and homovanillic acid sulfate. The fact that olive oil phenolic metabolites are able to bind LDL strengthens claims that these compounds act as in vivo antioxidants.