Olive oil phenolic compounds and high-density lipoprotein function

Mediterranean Diet, Energy Restriction, Physical Activity, and Atherogenicity of Very-Low Density Lipoproteins: Findings from Two Randomized Controlled Trials

SCOPE

Some very-low density lipoprotein (VLDL) properties may render them more pro-atherogenic. We aimed to assess whether a Mediterranean diet (MedDiet) or an energy-reduced MedDiet with increased physical activity improves them.

METHODS AND RESULTS

In a sample of the PREvención con DIeta MEDiterránea (PREDIMED) study, a 1-year intervention with MedDiet with extra-virgin olive oil (n = 89) or nuts (MedDiet-Nuts; n = 79) is compared with a low-fat diet (n = 90). In the PREDIMED-Plus study, a 1-year intervention with energy-reduced MedDiet and physical activity (n = 103) is compared with an ad libitum MedDiet (n = 101). VLDL levels of apolipoprotein C-I, C-III, triglycerides, and cholesterol; the apolipoprotein E-/C-I ratio; and VLDL ex-vivo triglyceride transfer are measured. In PREDIMED participants in both MedDiet groups combined, VLDL apolipoprotein C-III levels are nominally reduced (-0.023 SD units, 95% CI -0.44 to -0.014, p = 0.037). VLDL triglyceride transfer is nominally increased in the MedDiet-Nuts group (+0.39 SD units, 95% CI 0.012-0.78, p = 0.045). In PREDIMED-Plus, no inter-group differences are detected.

CONCLUSIONS

In older adults at high cardiovascular risk, MedDiet is associated with lower VLDL atherogenicity versus a low-fat diet. No differences are seen after an energy-reduced MedDiet with physical activity.

Lycopene-rich diets modulate HDL functionality and associated inflammatory markers without affecting lipoprotein size and distribution in moderately overweight, disease-free, middle-aged adults: A randomized controlled trial

Background

The consumption of lycopene-rich foods may lower cardiovascular disease (CVD) risk. Lycopene circulates in the blood bound to lipoproteins, including high-density lipoproteins (HDLs). Preliminary data from our group showed that increased consumption of tomato-based food or lycopene supplement in middle-aged subjects led to functional changes to HDL's sub-fractions, HDL₂ and HDL₃. These changes were also associated with a decrease in serum amyloid A (SAA), potentially enhancing their anti-atherogenic properties.

Objective

We carried out a comprehensive randomized controlled intervention trial with healthy middle-aged volunteers to assess whether the consumption of tomato-based foods or lycopene supplements affects HDL functionality and associated inflammatory markers, and lipoprotein subfractions size and distribution.

Design

Volunteers (225, aged 40–65 years) were randomly assigned to one of three dietary intervention groups and asked to consume a control diet (low in tomato-based foods, <10 mg lycopene/week), a lycopene-rich diet (224–350 mg lycopene/week), or the control diet with a lycopene supplement (70 mg lycopene/week). HDL₂ and HDL₃ were isolated by ultracentrifugation. Compliance was monitored by assessing lycopene concentration in serum. Systemic and HDL-associated inflammation was assessed by measuring SAA concentrations. HDL functionality was determined by monitoring paraoxonase-1 (PON-1), cholesteryl ester transfer protein (CETP), and lecithin cholesterol acyltransferase (LCAT) activities. The lipoprotein subfractions profile was assessed by NMR.

Results

Lycopene in serum and HDL significantly increased following consumption of both the high tomato diet and lycopene supplement (p ≤ 0.001 for both). Lycopene, either as a tomato-rich food or a supplement, enhanced both serum- and HDL₃-PON-1 activities (p ≤ 0.001 and p = 0.036, respectively), while significantly reducing HDL₃-SAA-related inflammation (p = 0.001). Lycopene supplement also significantly increased HDL₃-LCAT activity (p = 0.05), and reduced the activity of both HDL₂- and HDL₃-CETP (p = 0.005 and p = 0.002, respectively). These changes were not associated with changes in the subclasses distribution for all lipoprotein fractions or the size of lipoprotein subclasses.

Conclusion

Our results showed that dietary lycopene can significantly enhance HDL functionality, without associated changes in particle size and distribution, by modulating the activity of HDL-associated enzymes. Concomitantly, dietary lycopene significantly decreased serum- and HDL₃-associated SAA, confirming that SAA may represent a sensitive inflammatory biomarker to dietary change.

Clinical Trial Register

(https://www.isrctn.com), ISRCTN34203810.

Modification of High-Density Lipoprotein Functions by Diet and Other Lifestyle Changes: A Systematic Review of Randomized Controlled Trials

High-density lipoprotein (HDL) functional traits have emerged as relevant elements that may explain HDL antiatherogenic capacity better than HDL cholesterol levels. These properties have been improved in several lifestyle intervention trials. The aim of this systematic review is to summarize the results of such trials of the most commonly used dietary modifications (fatty acids, cholesterol, antioxidants, alcohol, and calorie restriction) and physical activity. Articles were screened from the Medline database until March 2021, and 118 randomized controlled trials were selected. Results from HDL functions and associated functional components were extracted, including cholesterol efflux capacity, cholesteryl ester transfer protein, lecithin-cholesterol acyltransferase, HDL antioxidant capacity, HDL oxidation status, paraoxonase-1 activity, HDL anti-inflammatory and endothelial protection capacity, HDL-associated phospholipase A2, HDL-associated serum amyloid A, and HDL-alpha-1-antitrypsin. In mainly short-term clinical trials, the consumption of monounsaturated and polyunsaturated fatty acids (particularly omega-3 in fish), and dietary antioxidants showed benefits to HDL functionality, especially in subjects with cardiovascular risk factors. In this regard, antioxidant-rich dietary patterns were able to improve HDL function in both healthy individuals and subjects at high cardiovascular risk. In addition, in randomized trial assays performed mainly in healthy individuals, reverse cholesterol transport with ethanol in moderate quantities enhanced HDL function. Nevertheless, the evidence summarized was of unclear quality and short-term nature and presented heterogeneity in lifestyle modifications, trial designs, and biochemical techniques for the assessment of HDL functions. Such findings should therefore be interpreted with caution. Large-scale, long-term, randomized, controlled trials in different populations and individuals with diverse pathologies are warranted.

Dietary Strategies to Improve Cardiovascular Health: Focus on Increasing High-Density Lipoprotein Functionality

Cardiovascular disease is one of the leading causes of morbidity and mortality worldwide, with increasing incidence. A cornerstone of cardiovascular disease prevention is lifestyle modification through dietary changes to influence various risk factors such as obesity, hypertension and diabetes. The effects of diet on cardiovascular health are complex. Some dietary components and metabolites directly affect the composition and structure of high-density lipoproteins (HDL) and increase anti-inflammatory and vasoprotective properties. HDLs are composed of distinct subpopulations of particles of varying size and composition that have several dynamic and context-dependent functions. The identification of potential dietary components that improve HDL functionality is currently an important research goal. One of the best-studied diets for cardiovascular health is the Mediterranean diet, consisting of fish, olive oil, fruits, vegetables, whole grains, legumes/nuts, and moderate consumption of alcohol, most commonly red wine. The Mediterranean diet, especially when supplemented with extra virgin olive oil rich in phenolic compounds, has been shown to markedly improve metrics of HDL functionality and reduce the burden, or even prevent the development of cardiovascular disease. Particularly, the phenolic compounds of extra virgin olive oil seem to exert the significant positive effects on HDL function. Moreover, supplementation of anthocyanins as well as antioxidants such as lycopene or the omega-3 fatty acid eicosapentaenoic acid improve parameters of HDL function. In this review, we aim to highlight recent discoveries on beneficial dietary patterns as well as nutritional components and their effects on cardiovascular health, focusing on HDL function.

Anti-Inflammatory Action of Dietary Wild Olive (Acebuche) Oil in the Retina of Hypertensive Mice

Inflammation plays a crucial role in the course of eye diseases, including many vascular retinopathies. Although olive oil is known to have beneficial effects against inflammatory processes, there is no information available on the anti-inflammatory potential of the wild olive tree (namely, acebuche (ACE) for the primitive Spanish lineages). Here we investigate the anti-inflammatory effects of ACE oil in the retina of a mouse model of arterial hypertension, which was experimentally induced by administration of L-NAME (NG-nitro-L-arginine-methyl-ester). The animals were fed supplements of ACE oil or extra virgin olive oil (EVOO, for comparative purposes). Retinal function was assessed by electroretinography (ERG), and different inflammation-related parameters were measured in the retina and choroid. Besides significant prevention of retinal dysfunction shown in ERG recordings, ACE oil-enriched diet upregulated the expression of the anti-inflammatory markers PPARγ, PPARα and IL-10, while reducing that of major proinflammatory biomarkers, IL-1β, IL-6, TNF-α and COX-2. This is the first report to highlight the anti-inflammatory properties of an ACE oil-enriched diet against hypertension-related retinal damage. Noteworthy, dietary supplementation with ACE oil yielded better results compared to a reference EVOO.

Beneficial effects of dietary supplementation with olive oil, oleic acid, or hydroxytyrosol in metabolic syndrome: Systematic review and meta-analysis

BACKGROUND AND AIMS

Olive oil and components might have a beneficial effect on Metabolic Syndrome (MetS). The aim of this review and meta-analysis was to assess whether those effects are related to hydroxytyrosol or oleic acid contents, or the combination of them as olive oil, and how powerful is this effect.

METHODS

A systematic literature search was performed in MEDLINE via Pubmed, Web of Science (WOS) core collection, and Virtual Health Library (VHL) via LILACS and IBECS (Spain). MeSH terms used were "obesity", "body weight", "body mass index", "adipose tissue", "lipid metabolism", "LDL", "HDL", "VLDL", "insulin resistance", "glucose", "insulin", "hypertension", "arterial pressure", "olive oil", "oleic acid", and other (non-MeSH) terms: "total antioxidant capacity", "total antioxidant status", "hydroxytyrosol" (PROSPERO ID: CRD42021247614). Results of the included studies were meta-analyzed with the RevMan 5.3 program, assuming a random effects model.

RESULTS

76 articles (67 different trials) were identified. Hydroxytyrosol had no effect on MetS [combined standardized mean differences (SMD) = 0.01 (CI 95%: [-0.23, 0.25], I² = 83%; p = 0.920)]. Oleic acid had no significant beneficial effect on MetS [SMD = 0.03 (CI 95%: [-0.01, 0.07], I² = 0%); p = 0.150], but it improved lipid profile [SMD = 0.06 (CI 95%: [-0.00, 0.12], I² = 0%); p = 0. 050]. Olive oil had no effect on MetS [SMD = -0.01 (CI 95%: [-0.05, 0.03]), I² = 55%; p = 0.550)]. The supplementation with hydroxytyrosol, oleic acid or olive oil showed a beneficial effect on antioxidant capacity related to components of MetS [SMD = 0.31 (CI 95%: [-0.34, 0.95], I² = 81%)]; p = 0.35).

CONCLUSION

Most articles compared olive oil and oleic acid with other strategies specially designed for MetS management. Our findings suggest that olive oil or oleic acid consumption are as good as the other strategies to manage MetS.

Extra Virgin Olive Oil Prevents the Age-Related Shifts of the Distribution of HDL Subclasses and Improves Their Functionality

High-density lipoproteins (HDL) maintain cholesterol homeostasis through the role they play in regulating reverse cholesterol transport (RCT), a process by which excess cholesterol is transported back to the liver for elimination. However, RCT can be altered in the presence of cardiovascular risk factors, such as aging, which contributes to the increase in the incidence of cardiovascular diseases (CVD). The present study was aimed at investigating the effect of extra virgin olive oil (EVOO) intake on the cholesterol efflux capacity (CEC) of HDL, and to elucidate on the mechanisms by which EVOO intake improves the anti-atherogenic activity of HDL. A total of 84 healthy women and men were enrolled and were distributed, according to age, into two groups: 27 young (31.81 ± 6.79 years) and 57 elderly (70.72 ± 5.6 years) subjects. The subjects in both groups were given 25 mL/d of extra virgin olive oil (EVOO) for 12 weeks. CEC was measured using J774 macrophages radiolabeled with tritiated cholesterol ((3H) cholesterol). HDL subclass distributions were analyzed using the Quantimetrix Lipoprint® system. The HDL from the elderly subjects exhibited a lower level of CEC, at 11.12% (p < 0.0001), than the HDL from the young subjects. The CEC of the elderly subjects returned to normal levels following 12 weeks of EVOO intake. An analysis of the distribution of HDL subclasses showed that HDL from the elderly subjects were composed of lower levels of large HDL (L-HDL) (p < 0.03) and higher levels of small HDL (S-HDL) (p < 0.002) compared to HDL from the young subjects. A multiple linear regression analysis revealed a positive correlation between CEC and L-HDL levels (r = 0.35 and p < 0.001) as well as an inverse correlation between CEC and S-HDL levels (r = -0.27 and p < 0.01). This correlation remained significant even when several variables, including age, sex, and BMI as well as low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and glucose levels (β = 0.28, p < 0.002, and β = 0.24, p = 0.01) were accounted for. Consuming EVOO for 12 weeks modulated the age-related difference in the distribution of HDL subclasses by reducing the level of S-HDL and increasing the level of intermediate-HDL/large-HDL (I-HDL/L-HDL) in the elderly subjects. The age-related alteration of the CEC of HDL was due, in part, to an alteration in the distribution of HDL subclasses. A diet enriched in EVOO improved the functionality of HDL through an increase in I-HDL/L-HDL and a decrease in S-HDL.

Mediterranean Diet and Atherothrombosis Biomarkers: A Randomized Controlled Trial

SCOPE

To assess whether following a Mediterranean diet (MedDiet) improves atherothrombosis biomarkers in high cardiovascular risk individuals.

METHODS AND RESULTS

In 358 random volunteers from the PREvención con DIeta MEDiterránea trial, the 1-year effects on atherothrombosis markers of an intervention with MedDiet, enriched with virgin olive oil (MedDiet-VOO; n = 120) or nuts (MedDiet-Nuts; n = 119) versus a low-fat control diet (n = 119), and whether large increments in MedDiet adherence (≥3 score points, versus compliance decreases) and intake changes in key food items are associated with 1-year differences in biomarkers. Differences are observed between 1-year changes in the MedDiet-VOO intervention and control diet on the activity of platelet activating factor acetylhydrolase in high-density lipoproteins (HDLs) (+7.5% [95% confidence interval: 0.17; 14.8]) and HDL-bound α₁ -antitrypsin levels (-6.1% [-11.8; -0.29]), and between the MedDiet-Nuts intervention and the control arm on non-esterified fatty acid concentrations (-9.3% [-18.1; -0.53]). Large MedDiet adherence increments are associated with less fibrinogen (-9.5% [-18.3; -0.60]) and non-esterified fatty acid concentrations (-16.7% [-31.7; -1.74]). Increases in nut, fruit, vegetable, and fatty fish consumption, and decreases in processed meat intake are linked to enhancements in biomarkers.

CONCLUSION

MedDiet improves atherothrombosis biomarkers in high cardiovascular risk individuals.

Retinoprotective Effect of Wild Olive (Acebuche) Oil-Enriched Diet against Ocular Oxidative Stress Induced by Arterial Hypertension

Oxidative stress plays an important role in the pathogenesis of ocular diseases, including hypertensive eye diseases. The beneficial effects of olive oil on cardiovascular diseases might rely on minor constituents. Currently, very little is known about the chemical composition and/or therapeutic effects of the cultivated olive tree’s counterpart, wild olive (also known in Spain as acebuche—ACE). Here, we aimed to analyze the antioxidant and retinoprotective effects of ACE oil on the eye of hypertensive mice made hypertensive via administration of NG-nitro-L-arginine-methyl-ester (L-NAME), which were subjected to a dietary supplementation with either ACE oil or extra virgin olive oil (EVOO) for comparison purposes. Deep analyses of major and minor compounds present in both oils was accompanied by blood pressure monitoring, morphometric analyses, as well as different determinations of oxidative stress-related parameters in retinal layers. Aside from its antihypertensive effect, an ACE oil-enriched diet reduced NADPH (nicotinamide adenine dinucleotide phosphate) oxidase activity/gene/protein expression (with a major implication of NADPH oxidase (NOX)2 isoform) in the retinas of hypertensive mice. Supplementation with ACE oil in hypertensive animals also improved alterations in nitric oxide bioavailability and in antioxidant enzyme profile. Interestingly, our findings show that the use of ACE oil resulted in better outcomes, compared with reference EVOO, against hypertension-related oxidative retinal damage.

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

PURPOSE

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.

METHODS

Three groups of mice were fed for 12 weeks 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.

RESULTS

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.

CONCLUSION

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.

Reverse Cholesterol Transport: Molecular Mechanisms and the Non-medical Approach to Enhance HDL Cholesterol

Dyslipidemia (high concentrations of LDL-c and low concentrations of HDL-c) is a major cause of cardiovascular events, which are the leading cause of death in the world. On the other hand, nutrition and regular exercise can be an interesting strategy to modulate lipid profile, acting as prevention or treatment, inhibiting the risk of diseases due to its anti-inflammatory and anti-atherogenic characteristics. Additionally, the possibility of controlling different training variables, such as type, intensity and recovery interval, can be used to maximize the benefits of exercise in promoting cardiovascular health. However, the mechanisms by which exercise and nutrients act in the regulation of cholesterol and its fractions, such as reverse cholesterol transport, receptors and transcription factors involved, such as PPARs and their role related to exercise, deserve further discussion. Therefore, the objective of this review is to debate about non-medical approaches to increase HDL-c, such as nutritional and training strategies, and to discuss the central mechanisms involved in the modulation of lipid profile during exercise, as well as that can be controlled by physical trainers or sports specialists in attempt to maximize the benefits promoted by exercise. The search for papers was performed in the databases: Medline (Pubmed), Science Direct, Scopus, Sport Discus, Web of Science, Scielo and Lilacs until February 2016.

Determinants of HDL Cholesterol Efflux Capacity after Virgin Olive Oil Ingestion: Interrelationships with Fluidity of HDL Monolayer

SCOPE

Cholesterol efflux capacity of HDL (CEC) is inversely associated with cardiovascular risk. HDL composition, fluidity, oxidation, and size are related with CEC. We aimed to assess which HDL parameters were CEC determinants after virgin olive oil (VOO) ingestion.

METHODS AND RESULTS

Post-hoc analyses from the VOHF study, a crossover intervention with three types of VOO. We assessed the relationship of 3-week changes in HDL-related variables after intervention periods with independence of the type of VOO. After univariate analyses, mixed linear models were fitted with variables related with CEC and fluidity. Fluidity and Apolipoprotein (Apo)A-I content in HDL was directly associated, and HDL oxidative status inversely, with CEC. A reduction in free cholesterol, an increase in triglycerides in HDL, and a decrease in small HDL particle number or an increase in HDL mean size, were associated to HDL fluidity.

CONCLUSIONS

HDL fluidity, ApoA-I concentration, and oxidative status are major determinants for CEC after VOO. The impact on CEC of changes in free cholesterol and triglycerides in HDL, and those of small HDL or HDL mean size, could be mechanistically linked through HDL fluidity. Our work points out novel therapeutic targets to improve HDL functionality in humans through nutritional or pharmacological interventions.

Mediterranean Diet Improves High-Density Lipoprotein Function in High-Cardiovascular-Risk Individuals: A Randomized Controlled Trial

BACKGROUND

The biological functions of high-density lipoproteins (HDLs) contribute to explaining the cardioprotective role of the lipoprotein beyond quantitative HDL cholesterol levels. A few small-scale interventions with a single antioxidant have improved some HDL functions. However, to date, no long-term, large-scale, randomized controlled trial has been conducted to assess the effects of an antioxidant-rich dietary pattern (such as a traditional Mediterranean diet [TMD]) on HDL function in humans.

METHODS

This study was performed in a random subsample of volunteers from the PREDIMED Study (Prevención con Dieta Mediterránea; n=296) after a 1-year intervention. We compared the effects of 2 TMDs, one enriched with virgin olive oil (TMD-VOO; n=100) and the other enriched with nuts (TMD-Nuts; n=100), with respect to a low-fat control diet (n=96). We assessed the effects of both TMDs on the role of HDL particles on reverse cholesterol transport (cholesterol efflux capacity, HDL ability to esterify cholesterol, and cholesteryl ester transfer protein activity), HDL antioxidant properties (paraoxonase-1 arylesterase activity and total HDL antioxidant capacity on low-density lipoproteins), and HDL vasodilatory capacity (HDL ability to induce the release of nitric oxide in endothelial cells). We also studied the effects of a TMD on several HDL quality-related characteristics (HDL particle oxidation, resistance against oxidative modification, main lipid and protein composition, and size distribution).

RESULTS

Both TMDs increased cholesterol efflux capacity relative to baseline (P=0.018 and P=0.013 for TMD-VOO and TMD-Nuts, respectively). The TMD-VOO intervention decreased cholesteryl ester transfer protein activity (relative to baseline, P=0.028) and increased HDL ability to esterify cholesterol, paraoxonase-1 arylesterase activity, and HDL vasodilatory capacity (relative to control, P=0.039, P=0.012, and P=0.026, respectively). Adherence to a TMD induced these beneficial changes by improving HDL oxidative status and composition. The 3 diets increased the percentage of large HDL particles (relative to baseline, P<0.001).

CONCLUSIONS

The TMD, especially when enriched with virgin olive oil, improved HDL atheroprotective functions in humans.

CLINICAL TRIAL REGISTRATION

URL: http://www.controlled-trials.com. Unique identifier: ISRCTN35739639.

Cardiovascular risk protection from the Mediterranean diet and olive oil. A transcriptomic update in humans

This review highlights the human studies that explore the benefits of the Mediterranean diet and olive oil, based on gene expression analysis. We summarized consistent human transcriptomic studies on cardiovascular risk, based on TMD and olive oil interventions, with real life doses and conditions. A literature review was carried out leading up to February 2016. The results show that the TMD, specially supplemented with virgin olive oil, produces beneficial changes in the transcriptomic response of relevant genes in cardiovascular risk such as CAT, GPX1 and SIRT2. p65 and MCP-1, IL1B, IL6, CXCL1, INF-γ, ARHGAP15 and IL7R, which are involved in inflammation; and ABCA1, SR-B1, PPARBP, PPARα, PPARγ, PPARδ, CD-36 and COX-1, which play an important role in cholesterol efflux. The available data illustrate a transcriptomic effect on atherosclerosis, inflammation and oxidative stress pathways as well as the mentioned genes.