Extra Virgin Olive Oil Consumption Research Articles

Cardiometabolic and Immunological Impacts of Extra Virgin Olive Oil Consumption in Overweight and Obese Older Adults: A Randomized Controlled Trial

Both aging and obesity are related to dysregulated immune function and increased risk of infection and chronic non‐infectious diseases. Dietary lipids are known to impact immune responses and cardiometabolic risk factors. We determined effect of replacing oils used in a typical American diet with extra virgin olive oil (EVOO) for 3 mo on immune and inflammatory responses and cardiometabolic risk factors in overweight and obese older adults. Forty‐one participants (aged 蠅65) who consumed a typical American diet were randomized into the control (CON, n=21) group to consume a mixture of corn, soybean oil and butter, and the olive oil (OO, n=20) group to consume EVOO to replace substitutable oils in their diet. At baseline and 3 mo, we measured cardiometabolic, and in vivo and ex vivo immunologic parameters. Compared to the CON group, the OO group showed decreased systolic blood pressure (P < 0.05), a strong trend toward increased plasma HDL‐C concentrations (P = 0.06), and increased T cell proliferative response (P < 0.05). No differences were found in T cell phenotype, cytokine production, and delayed‐type hypersensitivity skin response between the two groups. Our results indicate that substitution of oils used in a typical American diet with EVOO in overweight and obese older adults may have cardiometabolic and immunological health benefits.

Analyzing bivariate ordinal data with CUB margins

Statistical modelling for ordinal data has received a considerable attention in the literature, and a consolidated theory relying on Generalized Linear Model approach has been developed. In this article, we present an innovative technique for modelling bivariate ordinal data. In particular, we consider the method introduced by Plackett for constructing a one-parameter bivariate distribution from given margins, and we apply it in order to represent correlated ordinal variables which individually follows a CUB model. This is a univariate mixture distribution defined by the convex Combination of a Uniform and a shifted Binomial distribution whose parameters may be related to rater's covariates. The article shows how the bivariate distribution can be defined and how its characterizing parameter, which describes the association between the component random variables, can be related to the subject's covariates. The proposed approach is applied to the study of two key drivers of extra virgin olive oil consumption in Italy. The technique allows a representation of the data whose meaning can be easily interpreted providing useful information for management support.

Extravirgin Olive Oil Consumption Reduces Risk of Atrial Fibrillation

Background— The PREDIMED (Prevención con Dieta Mediterránea) primary prevention trial showed that a Mediterranean diet enriched with either extravirgin olive oil or mixed nuts reduces the incidence of stroke, myocardial infarction, and cardiovascular mortality. We assessed the effect of these diets on the incidence of atrial fibrillation in the PREDIMED trial. Methods and Results— Participants were randomly assigned to 1 of 3 diets: Mediterranean diet supplemented with extravirgin olive oil, Mediterranean diet supplemented with mixed nuts, or advice to follow a low-fat diet (control group). Some departures from individual randomization occurred in a subset of the trial because members of the same household and small clinics in one of the 11 recruiting centers were allocated by clusters instead of individually. Incident atrial fibrillation was adjudicated during follow-up by an events committee blinded to dietary group allocation. Among 6705 participants without prevalent atrial fibrillation at randomization, we observed 72 new cases of atrial fibrillation in the Mediterranean diet with extravirgin olive oil group, 92 in the Mediterranean diet with mixed nuts group, and 89 in the control group after median follow-up of 4.7 years. The Mediterranean diet with extravirgin olive oil significantly reduced the risk of atrial fibrillation (hazard ratio, 0.62; 95% confidence interval, 0.45–0.86 compared with the control group) after adjusting for propensity scores and using robust variance estimators to account for the intra-cluster correlations. No effect was found for the Mediterranean diet with nuts (hazard ratio, 0.86; 95% confidence interval, 0.63–1.16). In secondary analyses done after excluding all participants randomized in clusters, the results did not materially change. Conclusions— In the absence of proven interventions for the primary prevention of atrial fibrillation, this post hoc analysis of the PREDIMED trial suggests that a lower incidence of atrial fibrillation was found after an intervention with extravirgin olive oil in the context of a Mediterranean dietary pattern. Clinical Trial Registration— URL: http://www.controlled-trials.com . Unique identifier: ISRCTN35739639.

Olive oil intake and risk of cardiovascular disease and mortality in the PREDIMED Study.

BackgroundIt is unknown whether individuals at high cardiovascular risk sustain a benefit in cardiovascular disease from increased olive oil consumption. The aim was to assess the association between total olive oil intake, its varieties (extra virgin and common olive oil) and the risk of cardiovascular disease and mortality in a Mediterranean population at high cardiovascular risk.MethodsWe included 7,216 men and women at high cardiovascular risk, aged 55 to 80 years, from the PREvención con DIeta MEDiterránea (PREDIMED) study, a multicenter, randomized, controlled, clinical trial. Participants were randomized to one of three interventions: Mediterranean Diets supplemented with nuts or extra-virgin olive oil, or a control low-fat diet. The present analysis was conducted as an observational prospective cohort study. The median follow-up was 4.8 years. Cardiovascular disease (stroke, myocardial infarction and cardiovascular death) and mortality were ascertained by medical records and National Death Index. Olive oil consumption was evaluated with validated food frequency questionnaires. Multivariate Cox proportional hazards and generalized estimating equations were used to assess the association between baseline and yearly repeated measurements of olive oil intake, cardiovascular disease and mortality.ResultsDuring follow-up, 277 cardiovascular events and 323 deaths occurred. Participants in the highest energy-adjusted tertile of baseline total olive oil and extra-virgin olive oil consumption had 35% (HR: 0.65; 95% CI: 0.47 to 0.89) and 39% (HR: 0.61; 95% CI: 0.44 to 0.85) cardiovascular disease risk reduction, respectively, compared to the reference. Higher baseline total olive oil consumption was associated with 48% (HR: 0.52; 95% CI: 0.29 to 0.93) reduced risk of cardiovascular mortality. For each 10 g/d increase in extra-virgin olive oil consumption, cardiovascular disease and mortality risk decreased by 10% and 7%, respectively. No significant associations were found for cancer and all-cause mortality. The associations between cardiovascular events and extra virgin olive oil intake were significant in the Mediterranean diet intervention groups and not in the control group.ConclusionsOlive oil consumption, specifically the extra-virgin variety, is associated with reduced risks of cardiovascular disease and mortality in individuals at high cardiovascular risk.Trial registrationThis study was registered at controlled-trials.com (http://www.controlled-trials.com/ISRCTN35739639). International Standard Randomized Controlled Trial Number (ISRCTN): 35739639. Registration date: 5 October 2005.

Extra virgin olive oil (EVOO) consumption and antioxidant status in healthy institutionalized elderly humans

Recent studies show that the elderly have increased oxidative stress and impaired antioxidant defense systems. Our study aims to evaluate the effects of daily consumption of EVOO in the healthy institutionalized elderly. We studied anthropometric, biochemical and antioxidant parameters in 62 subjects aged 65–96 years after a 6-week daily intake of polyphenol-rich EVOO with high oleuropein derivative contents. Subjects were divided into a control group (CG) who maintained their dietary habits (n=39) and an olive group (OG) who consumed EVOO as the only added fat, plus a daily dose of 50ml (n=23). We found a significant reduction of total cholesterol (TC), HDL, LDL and TGs in OG subjects and a significant increase of HDL levels. There was no significant variation in the CG parameters. In OG the total antioxidant capacity (TAC) in plasma increased with significant differences over CG. Plasma hydroxytyrosol (OH-Tyr) concentration showed a significant increase after EVOO intervention. Daily consumption of EVOO was found to have positive effects on lipid profiles, OH-Tyr levels and TAC. The results also show a significant increase of catalase (CAT) in erythrocytes and a decrease (p<0.05) in superoxide dismutase (SOD) and glutathione peroxidase (GH-PX) activity after EVOO intake. To our knowledge, no other study has examined the effects of EVOO consumption on biochemical parameters, antioxidant capacity and antioxidant enzyme activity in healthy elderly subjects. In conclusion, our results show that nutritional intervention with EVOO improves antioxidant status in healthy elderly people.

Extra-virgin olive oil consumption reduces the age-related decrease in HDL and paraoxonase 1 anti-inflammatory activities

Paraoxonase 1 (PON1) is associated with HDL and modulates the antioxidant and anti-inflammatory role of HDL. The goals of the present study were to investigate the effect of ageing and the role of PON1 on the anti-inflammatory activity of HDL, and to determine whether extra-virgin olive oil (EVOO) consumption could improve the atheroprotective activity of HDL. HDL and PON1 were isolated from the plasma of ten young (Y-HDL and Y-PON1) and ten elderly (E-HDL and E-PON1) healthy volunteers before and after 12 weeks of EVOO consumption. Inflammation was assessed by measuring intracellular adhesion molecule 1 (ICAM-1) expression. THP-1 (human acute monocytic leukaemia cell line) monocyte chemotaxis was measured using a Boyden chamber. Oxidative damage to HDL was assessed by measuring conjugated diene formation and changes in electrophoretic migration. Y-HDL had more anti-inflammatory activity than E-HDL. The conjugated diene content and the electrophoretic mobility of E-HDL were higher than those of Y-HDL. Y-PON1 had significant anti-inflammatory activity, reducing ICAM-1 expression by 32·64 (SD 2·63)%, while E-PON1 had no significant effect. THP-1 chemotaxis measurements confirmed the ICAM-1 expression results. The 12 weeks of EVOO consumption significantly increased the anti-inflammatory activities of both HDL and PON1. The anti-inflammatory activity of HDL was modulated by PON1 and was lower in the elderly volunteers. EVOO consumption increased the anti-inflammatory effect of HDL and reduced the age-related decrease in anti-atherogenic activity.

Extra-virgin olive oil consumption improves the capacity of HDL to mediate cholesterol efflux and increases ABCA1 and ABCG1 expression in human macrophages

The present study was aimed to investigate the effect of 12 weeks of extra-virgin olive oil (EVOO) consumption on the capacity of HDL to promote cholesterol efflux (CE) and to determine which CE pathways are modulated by EVOO consumption. Whole HDL and HDL₂/HDL₃ subclasses were isolated from the plasma of twenty-six healthy volunteers before and after 12 weeks of EVOO consumption (25 ml/d). EVOO consumption increased the capacity of serum and HDL to mediate CE from THP-1, J774 macrophages and Fu5AH cells by 9·8-24·57 %, depending on the cell type. The increase in CE was independent of both HDL concentration and subclass distribution. The three HDL-mediated CE pathways (ATP-binding cassette (ABC) A1, ABCG1 and scavenger receptor class B type I (SR-BI)) were modulated by EVOO consumption. The fluidity of the phospholipidic layer of HDL increased by 13 % (P< 0·001) following EVOO consumption compared with baseline. EVOO consumption also increased the release of excess cholesterol from human monocyte-derived macrophages (HMDM) by 44 % (P< 0·001), and ABCA1 and ABCG1 mRNA transcription by 16·08 % (P< 0·001) and 35·79 % (P< 0·01), respectively. The protein expression of these two cholesterol transporters also increased after EVOO consumption. In contrast, SR-BI mRNA and protein expression in HMDM were significantly lower after 12 weeks of EVOO consumption. Incubating J774 macrophages with EVOO polyphenol extracts induced a concentration-dependent up-regulation of ABCA1 and ABCG1 expression in macrophages. After 12 weeks of EVOO consumption, the capacity of HDL to mediate CE was improved and the ability of HMDM to release excess cholesterol was enhanced by increasing the expression of ABCA1 and ABCG1 transporters.

Effect of extra virgin olive oil on glycaemia in healthy young subjects

In this approach we studied the glycaemia levels in 20 healthy young volunteers (26 ± 2 years), before and after a 30-day intake of 50 mL of extra virgin olive oil (EVOO). We selected an oil rich in phenolic compounds (523 mg/L) with a high content of secoiridoidic derivatives (over 94.5%). The findings from our study reveal a significant decrease of glycaemia from 89.6 ± 6.8 to 82.7 ± 10.3 mg/dL (p<0.05), related to a long term daily intake of the study EVOO, as the only added fat. A significant increment of the HDL cholesterol, from 68.7 ± 11.5 to 75.2 ± 4.9 mg/dL, was also highlighted. Total cholesterol, LDL, VLDL, triglycerides, and blood pressure did not show significant variation after the 30-day consumption of this EVOO. So far, few articles have described the influence of EVOO consumption, on plasma glucose levels in humans. This effect is observed in a group of healthy young humans. Moreover, we confirm that the level of free hydroxytyrosol (OH-Tyr) in plasma increased up to fourfold (p<0.05) after the 30-day intake of this EVOO. In addition, the excretion in urine of the main metabolite of OH-Tyr, homovanillic acid (HVA), significantly increased.

Oleuropein aglycon prevents cytotoxic amyloid aggregation of human amylin

Pancreatic amyloid deposits of amylin are a hallmark of Type II diabetes and considerable evidence indicates that amylin oligomers are cytotoxic to β-cells. Many efforts are presently spent to find out naturally occurring molecules, or to design synthetic ones, able to hinder amylin aggregation or to protect cells against aggregate cytotoxicity. In this context, a protective effect of some polyphenols against amyloid cytotoxicity was reported. Actually dietary polyphenols are endowed with multiple health benefits, and extra virgin olive oil is attracting increasing interest as a source of these substances. Here, we investigated the effects on amylin aggregation and cytotoxicity of the secoiridoid oleuropein aglycon, the main phenolic component of extra virgin olive oil. We found that oleuropein, when present during the aggregation of amylin, consistently prevented its cytotoxicity to RIN-5F pancreatic β-cells, as determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide test and caspase-3 activity assay. A lack of interaction with the cell membrane of amylin aggregates grown in the presence of oleuropein was shown by fluorescence microscopy and synthetic lipid vesicle permeabilization. Moreover, our ThT assay, circular dichroism analysis and electron microscopy images suggested that oleuropein interferes with amylin aggregation, resulting in a different path skipping the formation of toxic pre-fibrillar aggregates. These results provide a molecular basis for some of the benefits potentially coming from extra virgin olive oil consumption and pave the way to further studies on the possible pharmacological use of oleuropein to prevent or to slow down the progression of type II diabetes.

Antiatherogenicity of extra virgin olive oil and its enrichment with green tea polyphenols in the atherosclerotic apolipoprotein-E-deficient mice: enhanced macrophage cholesterol efflux

The antiatherogenic properties of extra virgin olive oil (EVOO) enriched with green tea polyphenols (GTPPs; hereafter called EVOO-GTPP), in comparison to EVOO, were studied in the atherosclerotic apolipoprotein-E-deficient (E 0) mice. E 0 mice (eight mice in each group) consumed EVOO or EVOO-GTPP (7 μl/mouse/day, for 2 months) by gavage feeding. The placebo group received only water. At the end of the study, blood samples, peritoneal macrophages and aortas were collected. Consumption of EVOO or EVOO-GTPP resulted in a minimal increase in serum total and high-density lipoprotein (HDL) cholesterol levels (by 12%) and in serum paraoxonase 1 activity (by 6% and 10%). EVOO-GTPP (but not EVOO) decreased the susceptibility of the mouse serum to AAPH-induced lipid peroxidation (by 18%), as compared to the placebo-treated mice. The major effect of both EVOO and EVOO-GTPP consumption was on HDL-mediated macrophage cholesterol efflux. Consumption of EVOO stimulated cholesterol efflux rate from mouse peritoneal macrophages (MPMs) by 42%, while EVOO-GTPP increased it by as much as 139%, as compared to MPMs from placebo-treated mice. Finally, the atherosclerotic lesion size of mice was significantly reduced by 11% or 20%, after consumption of EVOO or EVOO-GTPP, respectively. We thus conclude that EVOO possesses beneficial antiatherogenic effects, and its enrichment with GTPPs further improved these effects, leading to the attenuation of atherosclerosis development.

Insight Into ABCG1-Mediated Cholesterol Efflux

Macrophages in the arterial intima take up modified LDL and become cholesterol-ester laden foam cells, which are the primary cell type in newly formed fatty streak lesions, and which play an important role throughout lesion progression and plaque vulnerability. Macrophages can unload their excess cellular cholesterol stores via lipid efflux, the first step in the protective reverse cholesterol transport pathway. In this pathway, efflux of cellular cholesterol to extracellular acceptors, such as HDL and lipid-poor apolipoproteins, targets this cholesterol for delivery to the liver for metabolism and direct excretion into the bile. The mechanisms of cellular cholesterol efflux are the focus of intensive research, and this field was advanced greatly by the discovery of ABCA1 as the Tangier disease gene in 1999.1 Tangier disease subjects have almost no plasma HDL, and their cells have a complete deficiency in cholesterol and phospholipid efflux to apolipoprotein A-I (apoAI) and a partial defect in lipid efflux to HDL.2 Thus, it was apparent that there is more than one pathway for lipid efflux to HDL. In 2001, Schmitz and colleagues demonstrated that ABCG1, another member of the ABC gene superfamily, was upregulated by cholesterol in human macrophages, and that an ABCG1 antisense oligonucleotide that reduced ABCG1 expression also decreased lipid efflux to HDL.3 The role of ABCG1 in lipid efflux was confirmed in 2004 when Wang and colleagues and Edwards and colleagues showed that ABCG1 transfected cells had increased cholesterol efflux to HDL.4,5 See page 1310 In the current issue of Arteriosclerosis, Thrombosis, and Vascular Biology , Wang et al provide novel insights both into the regulation of ABCG1 activity and into aspects of the mechanism of ABCG1-mediated lipid efflux,6 which differentiate it from the mechanism of ABCA1-mediated lipid efflux. Their essential discovery is that treatment of cells with …