Extra Virgin Olive Oil Diet Research Articles

Recipe for Heart Health: A Randomized Crossover Trial on Cardiometabolic Effects of Extra Virgin Olive Oil Within a Whole-Food Plant-Based Vegan Diet.

Whole-food, plant-based vegan diets, low in oils, and Mediterranean diets, rich in extra virgin olive oil (EVOO), reduce cardiovascular disease risk factors. Optimal quantity of dietary fat, particularly EVOO, is unclear. In a randomized crossover trial with weekly cooking classes, adults with ≥5% cardiovascular disease risk followed a high (4 tablespoons/day) to low (<1 teaspoon/day) or low to high EVOO whole-food, plant-based diet for 4 weeks each, separated by a 1-week washout. The primary outcome was difference in low-density lipoprotein cholesterol (LDL-C) from baseline. Secondary measures were changes in additional cardiometabolic markers. Linear mixed models assessed changes from baseline between phases, with age, sex, and body weight change as covariates. In 40 participants, fat intake comprised 48% and 32% of energy during high and low EVOO phases, respectively. Both diets resulted in comparable reductions in LDL-C, total cholesterol, apolipoprotein B, high-density lipoprotein cholesterol, glucose, and high-sensitivity C-reactive protein (all P<0.05). With diet-sequence interactions for LDL-C, differences were detected between diets by diet order (mean±SEM high to low: Δ-12.7[5.9] mg/dL, P=0.04 versus low to high: Δ+15.8[6.8] mg/dL, P=0.02). Similarly, low to high order led to increased glucose, total cholesterol, and high-density lipoprotein cholesterol (all P<0.05). Over period 1, LDL-C reductions were -25.5(5.1) post-low versus -16.7(4.2) mg/dL post-high EVOO, P=0.162, which diminished over period 2. Both plant-based diet patterns improved cardiometabolic risk profiles compared with baseline diets, with more pronounced decreases in LDL-C after the low EVOO diet. Addition of EVOO after following a low intake pattern may impede further lipid reductions. URL: https://www.clinicaltrials.gov; Unique identifier: NCT04828447.

Characterization of Olive Oil Phenolic Extracts and Their Effects on the Aggregation of the Alzheimer's Amyloid-β Peptide and Tau.

The dietary consumption of extra virgin olive oil (EVOO) is believed to slow the progression of Alzheimer's disease (AD) symptoms. Its protective mechanisms are unclear, but specific EVOO phenolic compounds can individually impede the aggregation of amyloid-β (Aβ) peptides and the microtubule-associated protein tau, two important pathological manifestations of AD. It is unknown, however, whether the numerous and variable phenolic compounds that are consumed in dietary EVOO can collectively alter tau and Aβ aggregation as effectively as the individual compounds. The activity of these complex mixtures against Aβ and tau may be moderated by competition between active and nonactive phenolic components and by extensive derivatizations and isomerization. Here, phenolic mixtures extracted from two different EVOO sources are characterized and tested for how they modulate the aggregation of Aβ40 peptide and tau peptides in vitro. The chromatographic and NMR analysis of Greek and Saudi Arabian EVOO phenolic extracts reveals that they have different concentration profiles, and over 30 compounds are identified. Thioflavin T fluorescence and circular dichroism measurements show that relatively low concentrations (<20 μg/mL) of the Greek and Saudi extracts reduce the rate of Aβ40 aggregation and fibril mass, despite the extracts having different phenolic profiles. By contrast, the Greek extract reduces the rate of tau aggregation only at very high phenolic concentrations (>100 μg/mL). Most compounds in the extracts bind to preformed Aβ40 fibrils and release soluble Aβ oligomers that are mildly toxic to SH-SY5Y cells. Much higher (500 μg/mL) extract concentrations are required to remodel tau filaments into oligomers, and a minimal binding of phenolic compounds to the preformed filaments is observed. It is concluded that EVOO extracts having different phenol profiles are similarly capable of modulating Aβ40 aggregation and fibril morphology in vitro at relatively low concentrations but are less efficient at modulating tau aggregation. Over 2 M tonnes of EVOO are consumed globally each year as part of the Mediterranean diet, and the results here provide motivation for further clinical interrogation of the antiaggregation properties of EVOO as a potential protective mechanism against AD.

Metabolic and molecular effects of dietary extra virgin olive oil in blood and placenta of women with GDM.

At term, the TG/HDL cholesterol ratio, fatty acid binding protein 4 circulating levels, and maternal BMI were increased in the GDM patients, alterations prevented by the maternal diet enriched in EVOO. Although there were no changes in placental lipid levels and lipid profile, GDM placentas were thicker than controls and showed increased glycogen and collagen content, alterations prevented by the EVOO enriched diet. GDM placentas showed increases in megalin levels, in the expression of several genes involved in the endocytic pathway, and in miR-199, which targets these genes, alterations prevented by the maternal diet enriched in EVOO. We identified novel beneficial effects of an EVOO-enriched diet in GDM women, a diet capable of regulating maternal insulin resistance, the structure and metabolism of the placenta, and the placental endocytic pathway, suggesting effects that may be beneficial for fetal development.

Dual effects of extra virgin olive oil in acute wounds.

Extra virgin olive oil (EVOO) has proved beneficial effects in skin wound healing of chronic lesions; however, the effects of EVOO in acute wounds are not completely understood. This study investigated the effects of short-term and long-term administration of a diet rich in EVOO on acute wound healing. To check this, mice were fed with a diet rich in EVOO for 1 week (short term), 1 month, or 3 months (long term). The control group received a standard diet. Mouse macrophages were treated in vitro with EVOO or hydroxytyrosol (HT), which is the main EVOO polyphenol. Short-term administration of an EVOO rich diet in vivo increased lipid peroxidation and mRNA levels of pro-inflammatory cytokine levels and impaired acute wound closure. In contrast, long-term administration of an EVOO rich diet resulted in increased mRNA levels of anti-inflammatory cytokines and enhanced acute wound closure. In both in vivo and in vitro assays, the administration of EVOO or HT resulted in a predominantly anti-inflammatory macrophage phenotype. In conclusion, a diet rich in EVOO has a positive effect on acute wound healing that is dependent on the duration of EVOO administration. Short-term EVOO diet supplementation increases oxidative damage and pro-inflammatory responses, which impaired acute wound closure. On the other hand, long-term EVOO supplementation reduces oxidative damage and enhances anti-inflammatory responses, which improved acute wound closure. The effects of EVOO on oxidation and inflammation in acute wounds are linked to the EVOO polyphenol HT.

Evidence Supporting the Involvement of the Minority Compounds of Extra Virgin Olive Oil, through Gut Microbiota Modulation, in Some of the Dietary Benefits Related to Metabolic Syndrome in Comparison to Butter.

Extra virgin olive oil (EVOO) has proven to yield a better health outcome than other saturated fats widely used in the Western diet, including a distinct dysbiosis-preventive modulation of gut microbiota. Besides its high content in unsaturated fatty acids, EVOO also has an unsaponifiable polyphenol-enriched fraction that is lost when undergoing a depurative process that gives place to refined olive oil (ROO). Comparing the effects of both oils on the intestinal microbiota of mice can help us determine which benefits of EVOO are due to the unsaturated fatty acids, which remain the same in both, and which benefits are a consequence of its minority compounds, mainly polyphenols. In this work, we study these variations after only six weeks of diet, when physiological changes are not appreciated yet but intestinal microbial alterations can already be detected. Some of these bacterial deviations correlate in multiple regression models with ulterior physiological values, at twelve weeks of diet, including systolic blood pressure. Comparison between the EVOO and ROO diets reveals that some of these correlations can be explained by the type of fat that is present in the diet, while in other cases, such as the genus Desulfovibrio, can be better understood if the antimicrobial role of the virgin olive oil polyphenols is considered.

Molecular and metabolic effects of extra-virgin olive oil on the cardiovascular gene signature in rodents

Background and aimsOverweight and obesity are major risk factors for degenerative diseases, including cardiometabolic disorders and cancer. Research on fat and fatty acids’ type is attracting less attention than that on carbohydrates. High adherence to a Mediterranean diet is associated with a better prognosis. One characteristic of the Mediterranean diet is extra-virgin olive oil (EVOO) as the foremost source of dietary fat. EVOO is different from other vegetable oils because it contains peculiar “minor” components, mainly phenolic in nature. Even though olive oil is highly caloric, unrestricted use of olive oil in the PREDIMED trial did not result in weight gain. We sought to study the effects of EVOO in an appropriate mouse model of increased body weight. Furthermore, we explored the biochemical and metabolomic responses to EVOO consumption. Methods and resultsC57BL/6N male mice were weight-matched and fed ad libitum with the following diets, for 16 weeks: 1) saturated fatty acid diet (SFA) or 2) extra-virgin olive oil diet (EVOO), a custom-prepared diet, isocaloric compared to SFA, in which 82% of fat was replaced by high (poly)phenol EVOO. We evaluated glucose homeostasis, serum biochemistry and plasma metabolomics, in addition to cardiac and hepatic gene profile, and mitochondrial respiration rate. ConclusionReplacing saturated fatty acids (e.g. lard) with EVOO translates into moderate yet beneficial cardiometabolic and hepatic effects. Future research will further clarify the mechanisms of action of EVOO (poly)phenols and their role in a balanced diet.

Protective effects of extra virgin olive oil and exercise training on rat skeletal muscle against high-fat diet feeding

A diet high in saturated fat leads to skeletal muscle deteriorations including insulin resistance, mitochondrial dysfunction and muscle fiber atrophy. Consumption of long-chain polyunsaturated fatty acids and exercise have shown promise in ameliorating high-fat diet (HFD)-induced oxidative stress and inflammation. However, the impact of extra virgin olive oil (EVOO) on mitochondrial homeostasis in muscle is largely unknown. This study aimed to investigate whether 12 wks of EVOO feeding alone and in conjunction with endurance training could protect against metabolic and mitochondrial dysfunction rat muscle with HFD. Female Sprague-Dawley rats were divided into 4 groups fed a control diet (C), HFD, EVOO diet, and EVOO diet with training (EVOO+T). Mitochondrial enzyme activity and protein content decreased with HFD compared to C, but were restored with EVOO and EVOO+T. EVOO+T elevated muscle cytochrome c and PGC-1α levels. HFD increased muscle proteolytic markers and protein ubiquitination, whereas these effects were not seen in EVOO and EVOO+T. HFD suppressed mitochondrial fusion protein level while increasing fission protein levels, but were restored with EVOO and EVOO+T. Mitophagy marker PINK1 content decreased with HFD, but was unchanged in EVOO and EVOO+T. EVOO+T upregulated autophagy markers, along with decreased phosphorylated/dephosphorylated FoxO3 ratio. Antioxidants enzyme levels were upregulated by EVOO and EVOO+T, and EVOO+T reduced HFD-induced lipid peroxidation. In conclusion, HFD impaired muscle oxidative capacity, promoted protein ubiquitination and mitochondrial fission, and upregulated autophagy markers. Replacement of HFD with EVOO corrected the observed adverse effects, while exercise training in conjunction with EVOO provided additional protection to the muscle.

An extra virgin olive oil‐enriched chocolate spread positively modulates insulin‐resistance markers compared with a palm oil‐enriched one in healthy young adults: A double‐blind, cross‐over, randomised controlled trial

AimsTo investigate if extra virgin olive oil (EVOO) or palm oil enriched chocolate spreads consumption leads to different results in terms of plasma ceramides concentration, glucose and lipid metabolism, inflammatory markers and appetite regulation in young healthy subjects.MethodsIn a 2‐week, double‐blind, cross‐over, randomised controlled trial, 20 healthy, normal‐weight subjects with a mean age of 24.2 years (SD: 1.2), consumed chocolate spread snacks (73% of energy [%E] from fat, 20% from carbohydrates and 7% from proteins), providing 570 Kcal/day added to an isocaloric diet. The chocolate spreads were identical, except for the type of fat: EVOO oil, rich in monounsaturated fatty acids (MUFAs), or palm oil, rich in Saturated Fatty Acids (SFAs).ResultsEVOO‐enriched chocolate spread consumption led to better circulating sphingolipids and glucose profile, with reduced plasma ceramide C16:0, ceramide C16:0/ceramide C22:0‐ceramide C24:0 ratio and sphingomyelin C18:0 (P = 0.030, P= 0.032 and P = 0.042, respectively) compared to the palm oil‐enriched chocolate spread diet. HOMA‐IR and plasma insulin were lower, while the Quicki and the McAuley Index were higher after the EVOO diet compared to the palm oil diet (P = 0.046, P = 0.045, P = 0.018 and P = 0.039 respectively). Subjects maintained a stable weight throughout the study. No major significant changes in total cholesterol, triglycerides, HDL, inflammatory markers, and appetite‐regulating hormones/visual analogue scale were observed between the groups.ConclusionsPartially replacing SFAs with MUFAs in a chocolate‐based snack as part of a short‐term isocaloric diet in healthy individuals may limit SFAs detrimental effects on insulin sensitivity and decrease circulating harmful sphingolipids in young adults.

A high extra-virgin olive oil diet induces changes in metabolic pathways of experimental mammary tumors

Breast cancer is the most common malignancy in women worldwide, and environmental factors, especially diet, have a role in the etiology of this disease. This work aimed to investigate the influence of high fat diets (rich in corn oil or extra virgin olive oil -EVOO-) and the timing of dietary intervention (from weaning or after induction) on tumor metabolism in a seven,12-dimethylbenz[a]anthracene (DMBA)-induced breast cancer model in rat. The effects of lipids (oils and fatty acids) have also been investigated in MCF-7 cells. The results have confirmed different effects on tumor progression depending on the type of lipid. Molecular analysis at mRNA, protein and activity level of enzymes of the main metabolic pathways have also shown differences among groups. Thus, the animals fed with the EVOO-enriched diet developed tumors with less degree of clinical and morphological malignancy and showed modified glucose and mitochondrial metabolism when compared to the animals fed with the corn oil-enriched diet. Paradoxically, no clear influence on lipid metabolism by the high fat diets was observed. Considering previous studies on proliferation and apoptosis in the same samples, the results suggest that metabolic changes have a role in the molecular context that results in the modulation of different signaling pathways. Moreover, metabolic characteristics, without the context of other pathways, may not reflect tumor malignancy. The time of dietary intervention plays also a role, suggesting the importance of metabolic plasticity and the relation with mammary gland status when the tumor is induced.

Extra virgin olive oil improved body weight and insulin sensitivity in high fat diet-induced obese LDLr\u2212/\u2212.Leiden mice without attenuation of steatohepatitis

Dietary fatty acids play a role in the pathogenesis of obesity-associated non-alcoholic fatty liver disease (NAFLD), which is associated with insulin resistance (IR). Fatty acid composition is critical for IR and subsequent NAFLD development. Extra-virgin olive oil (EVOO) is the main source of monounsaturated fatty acids (MUFA) in Mediterranean diets. This study examined whether EVOO-containing high fat diets may prevent diet-induced NAFLD using Ldlr−/−. Leiden mice. In female Ldlr−/−.Leiden mice, the effects of the following high fat diets (HFDs) were examined: a lard-based HFD (HFD-L); an EVOO-based HFD (HFD-EVOO); a phenolic compounds-rich EVOO HFD (HFD-OL). We studied changes in body weight (BW), lipid profile, transaminases, glucose homeostasis, liver pathology and transcriptome. Both EVOO diets reduced body weight (BW) and improved insulin sensitivity. The EVOOs did not improve transaminase values and increased LDL-cholesterol and liver collagen content. EVOOs and HFD-L groups had comparable liver steatosis. The profibrotic effects were substantiated by an up-regulation of gene transcripts related to glutathione metabolism, chemokine signaling and NF-kappa-B activation and down-regulation of genes relevant for fatty acid metabolism. Collectivelly, EVOO intake improved weight gain and insulin sensitivity but not liver inflammation and fibrosis, which was supported by changes in hepatic genes expression.

Dietary Supplementation of Extra Virgin Olive Oil in Patients with Heart Failure with Preserved Ejection Fraction is Associated with Increases in Cardiorespiratory Fitness

Introduction Prevalence of Heart Failure with Preserved Ejection Fraction (HFpEF) is increasing worldwide, without effective therapies to reduce morbidity and mortality. Supplementation of extra virgin olive oil (EVOO) is a powerful primary prevention strategy against major cardiovascular events, but its effect on secondary prevention in HFpEF is unknown. Cardiorespiratory fitness (CRF), measured by peak oxygen consumption (VO2) on cardiopulmonary exercise testing (CPET), is a strong prognostic marker in HFpEF and increases in peak VO2 are linked to reductions in mortality. Our aim was to assess the effect of EVOO supplementation on measures of CRF in patients with HFpEF. Methods Nine consecutive patients were enrolled in the UFA-Preserved trial (NCT03310099), a dietitian-led 12-week pilot trial supplementing unsaturated fatty acid (UFA) rich foods, such as EVOO, in patients with HFpEF. Five-pass 24-hour dietary recalls were performed at baseline, 4, 8 and 12 week visits and analyzed with Nutrition Data Systems for Research (NDSR) software. Intake of EVOO in grams (g) was averaged across the 4, 8 and 12 week visits and average change from baseline was calculated. Peak VO2(mL.kg.min−1) and percent predicted value (% peak VO2) were measured with maximal CPET at baseline and 12 weeks along with oxygen uptake efficiency slope (OUES). Relationships between variables were analyzed with Spearman's rank test. Results are presented as median and interquartile range (IQR). Results Five subjects were female (56%) with a median age of 56 (50- 59) years. Baseline peak VO2 was 14.7 mL.kg.min−1 (11.3-22.1), % peak VO2 was 51.4 (43.8-59.4) and OUES was 1.87 (1.46-2.39). There was no EVOO intake on baseline dietary recalls, an increase in daily EVOO +23.6 g (12.0-47.6) (p=0.012) was observed between baseline and 12 weeks. EVOO consumption was significantly associated with positive improvements in peak VO2 (r=+0.850, p=0.004), % peak VO2 (r=+0.850, p=0.004), and OUES (r=+0.733,p=0.025) (Figure 1, panels A-C). Conclusion Dietary EVOO supplementation results in increased CRF in patients with HFpEF with no EVOO baseline intake. Further studies are warranted to confirm this finding and establish a basis for testing the effect of EVOO on CRF as well as major cardiovascular outcomes and to explore these effects across differing baseline intakes of EVOO.

High-fat but not normal-fat intake of extra virgin olive oil modulates the liver proteome of mice

The metabolic benefits of the Mediterranean diet have been largely attributed to its olive oil content. Whether the ingested fat amount is relevant to these effects is not clear. We thus compared the effects of high-fat and normal-fat intake of extra-virgin olive oil (EVOO) on the liver proteome. Three groups of mice were fed for 12weeks with either normal-fat diets containing either soybean oil (control, C) or EVOO (NO) or a high-fat EVOO diet (HO). Body weight and food intake were measured weekly and serum parameters were analyzed. The liver was processed for data-independent acquisition mass spectrometry-based proteomics. The differentially expressed proteins among the groups were submitted to pathway enrichment analysis. The consumption of HO diet reduced food intake and serum triglycerides, while it preserved body weight gain, adiposity, and glycemia. However, it increased serum cholesterol and liver mass. The proteomic analysis showed 98 altered proteins, which were allocated in 27 significantly enriched pathways. The pathway analysis suggested stimulation of mitochondrial and peroxissomal β-oxidation, and inhibition of lipid synthesis and gluconeogenesis in the HO group. Although the NO group failed to show significant liver proteome alterations, it presented reduced body fat, body weight gain, and serum triglycerides and glucose levels. The data indicate that the intake of the HO diet induced hepatic adjustments, which were partially successful in counteracting the detrimental outcomes of a high-fat feeding. Contrastingly, the NO diet had beneficial effects which were not accompanied by significant modifications on hepatic proteome.

Characterization of antihypertensive and cardioprotective effects of extra virgin olive oil against doxorubicin induced cardiomyopathy in rats

Context: The medicinal uses of olive fruit oil (Olea europaea) are clearly documented as an anti-inflammatory, anti-diabetic (type-2 DM), and to protect against heart diseases. Aims: To evaluate the therapeutic influence of extra virgin olive oil (EVOO) as an antihypertensive and cardioprotective against doxorubicin (DXR) induced cardiomyopathy in rats. Methods: Wistar rats were divided into five groups as group 1 (normal control), group 2 (disease control i.e., DXR-treated) and groups 3, 4 and 5 as therapeutic groups (i.e., DXR- treated rats plus 2.5%, 5%, and 10% EVOO in diet respectively). Cardiac injury was induced by the administration of DXR. Cardioprotective, anti-hypertensive and antioxidant potential of EVOO were studied by measuring different blood, serum, and tissue biomarkers, enzymes and hemodynamic parameters in disease control and experimental rat groups. Results: Hemodynamic parameters were significantly reduced in rats administered with 2.5%, 5%, and 10% EVOO as compared to group 2 rats at p&lt;0.05, p&lt;0.01, and p&lt;0.001 respectively. Serum levels of creatinine kinase, troponin T, CK-MB and LDH were found markedly reduced in rats fed with 10% dietary EVOO as compared to disease control rats (p&lt;0.01). Serum levels of antioxidant enzymes like GSH and SOD were found significantly higher in group 5 rats as compared to group 2 at p&lt;0.01, and p&lt;0.001, respectively. Conclusions: Dietary administration of EVOO has the potential to reduce drug-induced cardiomyopathies and sustained use of EVOO in diet could be cardioprotective and useful against high blood pressure.

High Oleic Acid Peanut Oil and Extra Virgin Olive Oil Supplementation Attenuate Metabolic Syndrome in Rats by Modulating the Gut Microbiota.

Unhealthy dietary patterns are important risk factors for metabolic syndrome (MS), which is associated with gut microbiota disorder. High oleic acid peanut oil (HOPO) and extra virgin olive oil (EVOO), considered as healthy dietary oil, are rich in oleic acid and bioactive phytochemicals, yet efficacy of MS prevention and mechanisms linking to gut microbiota remain obscure. Herein, we investigated HOPO and EVOO supplementation in attenuating diet-induced MS, and the potential mechanisms focusing on modulation of gut microbiota. Physiological, histological and biochemical parameters and gut microbiota profiles were compared among four groups fed respectively with the following diets for 12 weeks: normal chow diet with ordinary drinking water, high-fat diet with fructose drinking water, HOPO diet with fructose drinking water, and EVOO diet with fructose drinking water. HOPO or EVOO supplementation exhibit significant lower body weight gain, homeostasis model assessment-insulin resistance (HOMA-IR), and reduced liver steatosis. HOPO significantly reduced cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL) level, while EVOO reduced these levels without significant difference. HOPO and EVOO prevented gut disorder and significantly increased β-diversity and abundance of Bifidobacterium. Moreover, HOPO significantly decreased abundance of Lachnospiraceae and Blautia. These findings suggest that both HOPO and EVOO can attenuate diet-induced MS, associated with modulating gut microbiota.

Development of a LC-MS/MS method for urinary hydroxytyrosol as a marker for consumption of olive oil

The aim of this study was to develop and validate a LC-MS/MS method to quantitate hydroxytyrosol in urine for clinical studies to monitor compliance of consumption of dietary extra virgin olive oil. Both pre-analytical and analytical issues were examined. The stability of hydroxytyrosol was monitored in both urine and synthetic urine at four different temperatures (room temperature, 4 °C, −20 °C, or −80 °C) for four weeks either with or without the additive acetic acid. The LC-MS/MS method was validated by performing linearity, imprecision, recovery, and carryover studies.

Extra virgin olive oil diet intervention improves insulin resistance and islet performance in diet-induced diabetes in mice

Dietary composition plays an important role in the pathophysiology of type 2 diabetes. Monounsaturated fatty acid consumption has been positively associated with improved insulin sensitivity and β-cell function. We examined whether an extra virgin olive oil (EVOO) high fat diet (HFD) can improve glucose homeostasis. C57BL/6J mice were fed a standard diet or a lard-based HFD to induce type 2 diabetes. Then, HFD mice were fed with three different based HFD (lard, EVOO and EVOO rich in phenolic compounds) for 24 weeks. HFD-EVOO diets significantly improved glycemia, insulinemia, glucose tolerance, insulin sensitivity and insulin degradation. Moreover, EVOO diets reduced β-cell apoptosis, increased β-cell number and normalized islet glucose metabolism and glucose induced insulin secretion. No additional effects were observed by higher levels of phenolic compounds. Thus, EVOO intake regulated glucose homeostasis by improving insulin sensitivity and pancreatic β-cell function, in a type 2 diabetes HFD animal model.

Dietary Extra-Virgin Olive Oil Polyphenols Do Not Attenuate Colon Inflammation in Transgenic HLAB-27 Rats but Exert Hypocholesterolemic Effects through the Modulation of HMGCR and PPAR-α Gene Expression in the Liver

Background: Human studies have demonstrated that olive oil phenolic compounds reduce inflammatory markers associated with chronic diseases. Objectives: To explore the anti-inflammatory effects of extra-virgin olive oil polyphenols in an experimental model of inflammatory bowel disease (IBD). Methods: HLA-B27 transgenic rats were fed an AIN-76 diet containing 10% corn oil (CO) or extra-virgin olive oil with high (EVOO) or low phenolic content (ROO) for 3 months. Wild-type rats (WT) were fed the CO diet. Results: CO-fed HLA-B27 animals developed intestinal inflammation characterized by diarrhea, increased myeloperoxidase activity, and mucosal injury. None of these parameters were influenced by EVOO. Gene expression profiling indicated that proinflammatory pathways were upregulated in the colon mucosa of CO-fed HLA-B27 rats compared to WT, and this was further confirmed by RT-PCR for the iNOS, TNFα, and IL1β genes. EVOO significantly reduced TNFα gene expression in the colon mucosa and decreased total cholesterol blood levels compared to CO HLA-B27 rats (89.43 ± 3.66 vs. 111.5 ± 8.10 mg/dL, p < 0.05). This latter effect with EVOO was associated with reduced HMGCR and increased PPAR-α hepatic gene expression, compared to ROO. Conclusion: These data indicate that olive oil polyphenols do not control colon inflammation in HLA-B27 transgenic rats but exert a positive effect on blood lipids by reducing total cholesterol levels. This preliminary result suggests the need to explore the efficacy of EVOO rich in polyphenols as a complementary strategy for managing hypercholesterolemia and to potentially limit statin-associated myotoxicity.

Changes in Gut Microbiota Linked to a Reduction in Systolic Blood Pressure in Spontaneously Hypertensive Rats Fed an Extra Virgin Olive Oil-Enriched Diet.

Fat type in diet is responsible for specific changes in gut microbiota (GM). Extra virgin olive oil (EVOO) has been shown to be beneficial for blood pressure and to produce effects on GM. To analyze the cause-effect relationship between intestinal microbial changes and blood pressure, we studied the effect of EVOO on fecal microbiota and systolic blood pressure (SBP) levels in spontaneously hypertensive rats (SHR). SHR were fed either an enriched EVOO diet or a standard diet for a period of 12 weeks. At the end of the experimental period, the microbial profiles in the feces were studied in both groups by using PCR-denaturing gradient gel electrophoresis. Real-time PCR was used to quantify the selected bacterial groups. The results demonstrated significant differences when using Lactobacillus (p<0.05), clostridia XIV (p<0.01) and universal (p<0.05) primers. A significant (r=-0.475; p=0.04) inverse correlation between the abundance of clostridia XIV and SBP, which depends on the type of diet, was also observed. Finally, the results suggested an increase in the microbial diversity of the feces of the animals fed the EVOO diet. These results strongly connect the pattern of GM in SHR fed a diet enriched with EVOO to the lower levels of SBP observed in these animals at the end of the feeding period.

Dietary lipids differentially modulate the initiation of experimental breast carcinogenesis through their influence on hepatic xenobiotic metabolism and DNA damage in the mammary gland

Breast cancer is the most common malignancy among women worldwide. In addition to reproductive factors, environmental factors such as nutrition and xenobiotic exposure have a role in the etiology of this malignancy. A stimulating and a potentially protective effect on experimental breast cancer has been previously described for high corn oil and high extra-virgin olive oil diets, respectively. This work investigates the effect of these lipids on the metabolism of 7,12-dimethylbenz(a)anthracene (DMBA), a polycyclic aromatic hydrocarbon that can initiate carcinogenesis and its consequences in an experimental rat breast cancer model. The PUFA n-6-enriched diet increased expression of Phase I enzymes prior to DMBA administration and raised the activity of CYP1s in the hours immediately after induction, while reducing the activity of Phase II enzymes, mainly NQO1. The levels of reactive metabolites measured in plasma by GC–MS and DMBA-DNA adducts in the mammary gland of the animals fed the high corn oil diet were also higher than in the other groups. On the other hand, the high extra-virgin olive oil diet and the control low-fat diet exhibited better coordinated Phase I and Phase II activity, with a lower production of reactive metabolites and less DNA damage in the mammary gland. The concordance between these effects and the different efficacy of the carcinogenesis process due to the dietary treatment suggest that lipids may differently modify mammary gland susceptibility or resistance to cancer initiation over the exposure to environmental carcinogens. SummaryDietary lipids influence the initiation of DMBA-induced mammary cancer through the modulation of liver xenobiotic metabolism, formation of reactive metabolites and subsequent DNA damage in the target tissue.

Palliative effects of extra virgin olive oil, gallic acid, and lemongrass oil dietary supplementation on growth performance, digestibility, carcass traits, and antioxidant status of heat-stressed growing New Zealand White rabbits.

This study explored the effects of supplemental dietary extra virgin olive oil (EVOO), gallic acid (GA), or lemongrass essential oil (LGEO) on growth performance, nutrient digestibility, carcass traits, lipid peroxidation, hematological, and antioxidative status in growing rabbits under heat stress conditions. A total of 48 male growing New Zealand White rabbits were randomly divided into four equal groups, which received a basal diet without any supplementation or supplemented with 15g EVOO, 500mg GA, or 400mgLGEO/kg of diet, for eight consecutive weeks. Results revealed that the overall mean of temperature humidity index was 84.67±0.35, reflecting a state of severe heat stress. Moreover, dietary supplementation with EVOO, GA, or LGEO significantly increased live body weight and daily body weight gain but decreased both feed conversion ratio and daily water consumption. Additionally, a significant increase in both organic matter and crude protein digestibility besides a remarkable elevation in the nutritive values of digestible crude protein, total digestible nutrients, and digestible energy, as well as an increase in the numbers of WBCs, lymphocytes, and heterophils was significant in EVOO-supplemented rabbits. Supplementation with EVOO, GA, or LGEO in the heat-stressed growing rabbit's diet enhanced catalase activity and reduced glutathione content, whereas EVOO-treated rabbits had the highest values. Also, malondialdehyde activity was reduced in response to all tested additives. In conclusion, these findings suggested that addition of EVOO, GA, or LGEO in growing rabbit's diet could be used effectively to alleviate negative impacts of heat stress load on performance, nutrient digestibility, oxidative status, and hemato-biochemical features. Furthermore, among these additives, EVOO achieved the best effects.