Polyphenol rich olive oils improve lipoprotein particle atherogenic ratios and subclasses profile: A randomized, crossover, controlled trial

The Impact of the Mediterranean Diet and Lifestyle Intervention on Lipoprotein Subclass Profiles among Metabolic Syndrome Patients: Findings of a Randomized Controlled Trial

Metabolic syndrome (MetS) is associated with alterations of lipoprotein structure and function that can be characterized with advanced lipoprotein testing (ADLT). The effect of the Mediterranean diet (MedDiet) and weight loss on the lipoprotein subclass profile has been scarcely studied. Within the PREDIMED-Plus randomized controlled trial, a sub-study conducted at Bellvitge Hospital recruiting center evaluated the effects of a weight loss program based on an energy-reduced MedDiet (er-MedDiet) and physical activity (PA) promotion (intervention group) compared with energy-unrestricted MedDiet recommendations (control group) on ADLT-assessed lipoprotein subclasses. 202 patients with MetS (n = 107, intervention; n = 95, control) were included. Lipid profiles were determined, and ADLT was performed at baseline, 6, and 12 months. Linear mixed models were used to assess the effects of intervention on lipoprotein profiles. Compared to the control diet, at 12 months, the er-MedDiet+PA resulted in a significant additional 4.2 kg of body weight loss, a decrease in body mass index by 1.4 kg/m2, reduction in waist circumference by 2.2 cm, decreased triglycerides, LDL-cholesterol and non-HDL-cholesterol, and increased HDL-cholesterol. In er-MedDiet+PA participants, ADLT revealed a decrease in small dense-LDL-cholesterol (sd-LDL-C), intermediate-density lipoproteins, VLDL-triglyceride, and HDL-Triglyceride, and an increase in large LDL and large VLDL particles. In conclusion, compared to an ad libitum MedDiet (control group), er-MedDiet+PA decreased plasma triglycerides and the triglyceride content in HDL and VLDL particles, decreased sd-LDL-C, and increased large LDL particles, indicating beneficial changes against cardiovascular disease.

Olive Oil Polyphenols Improve HDL Cholesterol and Promote Maintenance of Lipid Metabolism: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

In 2011, the European Food Safety Authority (EFSA) accorded a health claim to olive oil polyphenols in that they protected LDL particles from oxidative damage. However, limited scientific evidence has so far failed to confer any claim of function on the maintenance of normal lipid metabolism. We performed a systematic review and meta-analysis of human RCTs, evaluating the effect of olive oil polyphenol administration on lipid profiles. Previous literature was acquired from six electronic databases until June 2023. A total of 75 articles were retrieved and screened for inclusion criteria, which resulted in the selection of 10 RCTs that evaluated the effect of daily exposure to olive oil polyphenols on serum lipids in adults. Meta-analyses were built by tertiles of outcomes, as follows: low (0-68 mg/kg), medium (68-320 mg/kg), and high (320-600 mg/kg) polyphenols for HDL and LDL cholesterol (HDL-C and LDL-C, respectively), and low (0-59.3 mg/kg), medium (59.3-268 mg/kg), and high (268-600 mg/kg) polyphenols for total cholesterol (TC). The study protocol was registered on PROSPERO (registration code: CRD42023403383). The study design was predominantly cross-over (n = 8 of 10) but also included parallel (n = 2 of 10). The study population was predominantly European and healthy. Daily consumption of olive oil polyphenols did not affect TC levels and only slightly significantly reduced LDL-C, with WMD statistically significant only for high daily consumption of olive oil polyphenols (WMD -4.28, 95%CI -5.78 to -2.77). Instead, our data found a statistically significant HDL-C enhancing effect (WMD pooled effect model: 1.13, 95%CI 0.45; 1.80, heterogeneity 38%, p = 0.04) with WMD by daily exposure level showing a statistically significant improvement effect for low (WMD 0.66, 95%CI 0.10-1.23), medium (WMD 1.36, 95%CI 0.76-1.95), and high (WMD 1.13, 95%CI 0.45-1.80) olive oil polyphenol consumptions. Olive oil polyphenols contribute toward maintaining lipid metabolism. Thus, food labeling regulations should stress this health feature of olive oil, whereby a declaration of the olive oil polyphenol content should be added to products on the market. Consumers need to be aware of the quality and possible health effects of any products they consume, and enforcement of nutrition labels offers the best way of providing this information.

Neuroprotective Panel of Olive Polyphenols: Mechanisms of Action, Anti-Demyelination, and Anti-Stroke Properties

Neurological diseases such as stroke and multiple sclerosis are associated with high morbidity and mortality, long-term disability, and social and economic burden. Therefore, they represent a major challenge for medical treatment. Numerous evidences support the beneficial effects of polyphenols from olive trees, which can alleviate or even prevent demyelination, neurodegeneration, cerebrovascular diseases, and stroke. Polyphenols from olive oils, especially extra virgin olive oil, olive leaves, olive leaf extract, and from other olive tree derivatives, alleviate inflammation and oxidative stress, two major factors in demyelination. In addition, they reduce the risk of stroke due to their multiple anti-stroke effects, such as anti-atherosclerotic, antihypertensive, antioxidant, anti-inflammatory, hypocholesterolemic, hypoglycemic, and anti-thrombotic effects. In addition, olive polyphenols have beneficial effects on the plasma lipid profiles and insulin sensitivity in obese individuals. This review provides an updated version of the beneficial properties and mechanisms of action of olive polyphenols against demyelination in the prevention/mitigation of multiple sclerosis, the most common non-traumatic neurological cause of impairment in younger adults, and against cerebral insult with increasing incidence, that has already reached epidemic proportions.

Therapeutic Properties and Use of Extra Virgin Olive Oil in Clinical Nutrition: A Narrative Review and Literature Update

Extra virgin olive oil (EVOO) is a cornerstone of the Mediterranean diet (MedD). In this narrative review, we synthesize and illustrate the various characteristics and clinical applications of EVOO and its components—such as oleic acid, hydroxytyrosol, and oleuropein—in the field of clinical nutrition and dietetics. The evidence is split into diet therapy, oleic acid-based enteral nutrition formulations and oral supplementation formulations, oleic acid-based parenteral nutrition, and nutraceutical supplementation of minor components of EVOO. EVOO has diverse beneficial health properties, and current evidence supports the use of whole EVOO in diet therapy and the supplementation of its minor components to improve cardiovascular health, lipoprotein metabolism, and diabetes mellitus in clinical nutrition. Nevertheless, more intervention studies in humans are needed to chisel specific recommendations for its therapeutic use through different formulations in other specific diseases and clinical populations.

The Effect of Dietary Interventions on Hypertriglyceridemia: From Public Health to Molecular Nutrition Evidence

Approximately 25–50% of the population worldwide exhibits serum triglycerides (TG) (≥150 mg/dL) which are associated with an increased level of highly atherogenic remnant-like particles, non-alcoholic fatty liver disease, and pancreatitis risk. High serum TG levels could be related to cardiovascular disease, which is the most prevalent cause of mortality in Western countries. The etiology of hypertriglyceridemia (HTG) is multifactorial and can be classified as primary and secondary causes. Among the primary causes are genetic disorders. On the other hand, secondary causes of HTG comprise lifestyle factors, medical conditions, and drugs. Among lifestyle changes, adequate diets and nutrition are the initial steps to treat and prevent serum lipid alterations. Dietary intervention for HTG is recommended in order to modify the amount of macronutrients. Macronutrient distribution changes such as fat or protein, low-carbohydrate diets, and caloric restriction seem to be effective strategies in reducing TG levels. Particularly, the Mediterranean diet is the dietary pattern with the most consistent evidence for efficacy in HTG while the use of omega-3 supplements consumption is the dietary component with the highest number of randomized clinical trials (RCT) carried out with effective results on reducing TG. The aim of this review was to provide a better comprehension between human nutrition and lipid metabolism.

Olive oil consumption and its repercussions on lipid metabolism

Consumption of highly processed foods, such as those high in trans fats and free sugars, coupled with sedentarism and chronic stress increases the risk of obesity and cardiometabolic disorders, while adherence to a Mediterranean diet is inversely associated with the prevalence of such diseases. Olive oil is the main source of fat in the Mediterranean diet. Data accumulated thus far show consumption of extra virgin, (poly)phenol-rich olive oil to be associated with specific health benefits. Of note, recommendations for consumption based on health claims refer to the phenolic content of extra virgin olive oil as beneficial. However, even though foods rich in monounsaturated fatty acids, such as olive oil, are healthier than foods rich in saturated and trans fats, their inordinate use can lead to adverse effects on health. The aim of this review was to summarize the data on olive oil consumption worldwide and to critically examine the literature on the potential adverse effects of olive oil and its main components, particularly any effects on lipid metabolism. As demonstrated by substantial evidence, extra virgin olive oil is healthful and should be preferentially used within the context of a balanced diet, but excessive consumption may lead to adverse consequences.

Virgin Olive Oil Phenolic Compounds Modulate the HDL Lipidome in Hypercholesterolaemic Subjects: A Lipidomic Analysis of the VOHF Study

Scope

The lipidomic analysis of high‐density lipoprotein (HDL) could be useful to identify new biomarkers of HDL function.

Methods and results

A randomized, controlled, double‐blind, crossover trial (33 hypercholesterolaemic subjects) is performed with a control virgin olive oil (VOO), VOO enriched with its own phenolic compounds (FVOO), or VOO enriched with additional phenolic compounds from thyme (FVOOT) for 3 weeks. HDL lipidomic analyses are performed using the Lipidyzer platform. VOO and FVOO intake increase monounsaturated‐fatty acids (FAs) and decrease saturated and polyunsaturated FAs in triacylglyceride (TAG) species, among others species. In contrast, FVOOT intake does not induce these FAs changes. The decrease in TAG52:3(FA16:0) after VOO intake and the decrease in TAG52:5(FA18:2) after FVOO intake are inversely associated with changes in HDL resistance to oxidation. After FVOO intake, the decrease in TAG54:6(FA18:2) in HDL is inversely associated with changes in HDL cholesterol efflux capacity.

Conclusion

VOO and FVOO consumption has an impact on the HDL lipidome, in particular TAG species. Although TAGs are minor components of HDL mass, the observed changes in TAG modulated HDL functionality towards a cardioprotective mode. The assessment of the HDL lipidome is a valuable approach to identify and characterize new biomarkers of HDL function.

Insight into the potential application of polyphenol-rich dietary intervention in degenerative disease management

In recent times, a great number of plants have been studied in order to identify new components with nutraceutical properties, among which are polyphenols. Dietary polyphenols represent a large group of bioactive molecules widely found in the food of plant origin and they have been found able to prevent the onset and progression of degenerative diseases, and to reduce and control their symptoms. These health protective effects have been mainly related to their antioxidant and anti-inflammatory properties. However, it must be considered that the application of isolated polyphenols as nutraceuticals is quite limited due to their poor systemic distribution and relative bioavailability. The present review highlights the potential effect of dietary intervention with polyphenol-rich food and plant extracts in patients with cancer, diabetes and neurodegenerative, autoimmune, cardiovascular and ophthalmic diseases, as well as the possible molecular mechanisms of action suggested in numerous studies with animal models.

Efficacy of Polyphenols in the Management of Dyslipidemia: A Focus on Clinical Studies

Polyphenols (PLPs), phytochemicals found in a wide range of plant-based foods, have gained extensive attention in view of their antioxidant, anti-inflammatory, immunomodulatory and several additional beneficial activities. The health-promoting effects noted in animal models of various non-communicable diseases explain the growing interest in these molecules. In particular, in vitro and animal studies reported an attenuation of lipid disorders in response to PLPs. However, despite promising preclinical investigations, the effectiveness of PLPs in human dyslipidemia (DLP) is less clear and necessitates revision of available literature. Therefore, the present review analyzes the role of PLPs in managing clinical DLP, notably by dissecting their potential in ameliorating lipid/lipoprotein metabolism and alleviating hyperlipidemia, both postprandially and in long-term interventions. To this end, PubMed was used for article search. The search terms included polyphenols, lipids, triglycerides, cholesterol, LDL-cholesterol and /or HDL-cholesterol. The critical examination of the trials published to date illustrates certain benefits on blood lipids along with co-morbidities in participant’s health status. However, inconsistent results document significant research gaps, potentially owing to study heterogeneity and lack of rigor in establishing PLP bioavailability during supplementation. This underlines the need for further efforts in order to elucidate and support a potential role of PLPs in fighting DLP.

Effect of polyphenol-rich extra-virgin olive oil on lipid profile and inflammatory biomarkers in patients undergoing coronary angiography: a randomised, controlled, clinical trial

The present study was conducted to compare the effects of high polyphenol extra-virgin olive oil (EVOO) with low polyphenol refined olive oil (ROO) on some cardiovascular risk factors in patients undergoing coronary angiography. In a randomised, controlled, parallel-arm, clinical trial, 40 patients with at least one classic cardiovascular risk factor who referred to coronary angiography were randomly allocated to two groups and receied 25 mL EVOO or ROO daily for 6 weeks. Plasma LDL-cholesterol significantly reduced in EVOO group (-9.52 ± 20.44 vs 8.68 ± 18.77 mg/dL, p = .007 for EVOO and ROO respectively). EVOO resulted in a significant reduction in plasma CRP (-0.40 ± 0.52 vs 0.007 ± 0.42 mg/L, p = .01 for EVOO and ROO respectively) and increased ex-vivo whole blood LPS-stimulated IL-10 production (12.13 ± 33.64 vs -17.47 ± 49.04 pg/mL, p = .035 for EVOO and ROO respectively). Daily consumption of polyphenol-rich EVOO in subjects who have been under medical treatment with risk-reducing agents could additionally improve LDL-C and selected inflammatory markers. Trial Registration Number: NCT03796780.

The effect of olive leaf extract on cardiovascular health markers: a randomized placebo-controlled clinical trial

Purpose

Overweight and obesity are associated with many health problems, including cardiovascular disease (CVD). Evidence from previous studies has shown that extracts from olive leaves rich in olive phenolics are able to positively affect CVD risk factors, such as high blood pressure and dyslipidemia. The aim of this study was to investigate the effect of 8-week olive leaf extract (OLE) administration on blood lipid profiles in overweight/obese subjects with mildly elevated cholesterol levels.

Methods

In this randomized, double-blind, placebo-controlled study, 77 healthy adult overweight/obese subjects (aged 56 ± 10 years and BMI 29.0 ± 2.7 kg/m²) with total cholesterol levels of 5.0–8.0 mmol/L (5.9 ± 0.7 mmol/L) were randomly assigned to receive 500 mg of OLE (n = 39) or placebo (n = 38) for 8 weeks. In total, 74 subjects completed the entire study protocol. At baseline, after 4 weeks, and after 8 weeks of supplementation, blood lipid profiles, oxidized low-density lipoprotein (oxLDL), blood pressure, glucose, and insulin levels were assessed. In addition, liver function parameters were measured at baseline and after 8 weeks.

Results

OLE supplementation did not significantly affect blood lipid levels after 4 weeks or after 8 weeks compared to placebo (all p > 0.05). For oxLDL, blood pressure, glucose, and insulin levels and liver function parameters, also no statistically significant differences were found between the two intervention groups (all p > 0.05).

Conclusions

Blood lipid profiles were not significantly affected by 8 weeks OLE supplementation in overweight/obese subjects with mildly elevated cholesterol levels.

Trial registered

The trial has been registered at ClinicalTrials.gov (NCT02990637).

Electronic supplementary material

The online version of this article (10.1007/s00394-020-02397-9) contains supplementary material, which is available to authorized users.

A review on management of cardiovascular diseases by olive polyphenols

Noncommunicable diseases have increasingly grown the cause of morbidities and mortalities worldwide. Among them, cardiovascular diseases (CVDs) continue to be the major contributor to deaths. CVDs are common in the urban community population due to the substandard living conditions, which have a significant impact on the healthcare system, and over 23 million human beings are anticipated to suffer from the CVDs before 2030. At the moment, CVD physicians are immediately advancing both primary and secondary prevention modalities in high-risk populations. The cornerstone of CVD prevention is a healthy lifestyle that is more cost-effective than the treatments after disease onset. In fact, in the present scenario, comprehensive research conducted on food plant components is potentially efficacious in reducing some highly prevalent CVD risk factors, such as hypercholesterolemia, hypertension, and atherosclerosis. Polyphenols of olive oil (OO), virgin olive oil (VOO), and extra virgin olive oil contribute an essential role for the management of CVDs. Olive oil induces cardioprotective effects due to the presence of a plethora of polyphenolic compounds, for example, oleuropein (OL), tyrosol, and hydroxytyrosol. The present study examines the bioavailability and absorption of major olive bioactive compounds, for instance, oleacein, oleocanthal, OL, and tyrosol. This review also elucidates the snobbish connection of olive polyphenols (OP) and the potential mechanism involved in combating various CVD results taken up from the in vitro and in vivo studies, such as animal and human model studies.

A Newly Developed Diabetes Risk Index, Based on Lipoprotein Subfractions and Branched Chain Amino Acids, is Associated with Incident Type 2 Diabetes Mellitus in the PREVEND Cohort

Objective: Evaluate the ability of a newly developed diabetes risk score, the Diabetes Risk Index (DRI), to predict incident type 2 diabetes mellitus (T2D) in a large adult population. Methods: The DRI was developed by combining the Lipoprotein Insulin Resistance Index (LP-IR), calculated from 6 lipoprotein subspecies and size parameters, and the branched chain amino acids, valine and leucine, all of which have been shown previously to be associated with future T2D. DRI scores were calculated in a total of 6134 nondiabetic men and women in the Prevention of Renal and Vascular End-Stage Disease (PREVEND) Study. Cox proportional hazards regression was used to evaluate the association of DRI scores with incident T2D. Results: During a median follow-up of 8.5 years, 306 new T2D cases were ascertained. In analyses adjusted for age and sex, there was a significant association between DRI scores and incident T2D with the hazard ratio (HR) for the highest versus lowest quartile being 12.07 (95% confidence interval: 6.97–20.89, p < 0.001). After additional adjustment for body mass index (BMI), family history of T2D, alcohol consumption, diastolic blood pressure, total cholesterol, triglycerides, HDL cholesterol and HOMA-IR, the HR was attenuated but remained significant (HR 3.20 (1.73–5.95), p = 0.001). Similar results were obtained when DRI was analyzed as HR per 1 SD increase (HR 1.37 (1.14–1.65), p < 0.001). The Kaplan–Meier plot demonstrated that patients in the highest quartile of DRI scores presented at higher risk (p-value for log-rank test <0.001). Conclusions: Higher DRI scores are associated with an increased risk of T2D. The association is independent of clinical risk factors for T2D including HOMA-IR, BMI and conventional lipids.

Interactions of dietary polyphenols with epithelial lipids: advances from membrane and cell models in the study of polyphenol absorption, transport and delivery to the epithelium

Currently, diet-related diseases such as diabetes, obesity, hypertension, and cardiovascular diseases account for 70% of all global deaths. To counteract the rising prevalence of non-communicable diseases governments are investing in persuasive educational campaigns toward the ingestion of fresh fruits and vegetables. The intake of dietary polyphenols abundant in Mediterranean and Nordic-type diets holds great potential as nutritional strategies in the management of diet-related diseases. However, the successful implementation of healthy nutritional strategies relies on a pleasant sensory perception in the mouth able to persuade consumers to adopt polyphenol-rich diets and on a deeper understanding on the chemical modifications, that affect not only their chemical properties but also their physical interaction with epithelial lipids and in turn their permeability, location within the lipid bilayer, toxicity and biological activity, and fate during absorption at the gastro-intestinal epithelium, transport in circulation and delivery to the endothelium. In this paper, we review the current knowledge on the interactions between polyphenols and their metabolites with membrane lipids in artificial membranes and epithelial cell models (oral, stomach, gut and endothelium) and the findings from polyphenol-lipid interactions to physiological processes such as oral taste perception, gastrointestinal absorption and endothelial health. Finally, we discuss the limitations and challenges associated with the current experimental approaches in membrane and cell model studies and the potential of polyphenol-rich diets in the quest for personalized nutritional strategies ("personalized nutrition") to assist in the prevention, treatment, and management of non-communicable diseases in an increasingly aged population.

Red Blood Cells and Lipoproteins: Important Reservoirs and Transporters of Polyphenols and Their Metabolites

Dietary polyphenols are protective for chronic diseases. Their blood transport has not been well investigated. This work examines multiple classes of polyphenols and their interactions with albumin, lipoproteins, and red blood cell (RBC) compartments using four models and determines the % polyphenol in each compartment studied. The RBC alone model showed a dose-response polyphenol association with RBCs. A blood model with flavanones determined the % polyphenol that was inside RBCs and bound to the surface using a new albumin washing procedure. It was shown that RBCs can methylate flavanones. The whole blood model separated the polyphenol into four compartments with the aid of affinity chromatography. More polyphenols were found with albumin and lipoproteins (high-density lipoproteins and low-density lipoproteins) than with RBCs. In the plasma model, the polyphenols associated almost equally between lipoproteins and albumin. RBCs and lipoproteins are shown to be important reservoirs and transporters of polyphenols in blood.

Virgin Olive Oil Quality Is Affected by the Microbiota that Comprise the Biotic Fraction of the Oil

This review summarizes the current knowledge on the effects of oil-borne yeasts on the physicochemical, sensorial, and health-related characteristics of virgin olive oil (VOO) during storage. Bacteria, yeasts, and molds constitute the biotic fraction of freshly produced VOO. During storage, the bacteria and molds often die after a short period, while the yeasts survive and condition the quality of VOO. To date, approximately twenty-four yeast species have been isolated from different types of olive oil and its by-products, and seven of these species have been identified as new species. The activity of some yeasts of the biotic fraction of olive oil improves the sensorial characteristics of VOO. Some yeasts can also worsen the quality of the product by allowing the appearance of defects, oxidation of polar phenols, and triacylglycerol hydrolysis. Some yeast species of VOO show in vitro beneficial health effects, such as probiotic and antioxidant activities.

Is Extra Virgin Olive Oil an Ally for Women's and Men's Cardiovascular Health?

Noncommunicable diseases are long-lasting and slowly progressive and are the leading causes of death and disability. They include cardiovascular diseases (CVD) and diabetes mellitus (DM) that are rising worldwide, with CVD being the leading cause of death in developed countries. Thus, there is a need to find new preventive and therapeutic approaches. Polyphenols seem to have cardioprotective properties; among them, polyphenols and/or minor polar compounds of extra virgin olive oil (EVOO) are attracting special interest. In consideration of numerous sex differences present in CVD and DM, in this narrative review, we applied "gender glasses." Globally, it emerges that olive oil and its derivatives exert some anti-inflammatory and antioxidant effects, modulate glucose metabolism, and ameliorate endothelial dysfunction. However, as in prescription drugs, also in this case there is an important gender bias because the majority of the preclinical studies are performed on male animals, and the sex of donors of cells is not often known; thus a sex/gender bias characterizes preclinical research. There are numerous clinical studies that seem to suggest the benefits of EVOO and its derivatives in CVD; however, these studies have numerous limitations, presenting also a considerable heterogeneity across the interventions. Among limitations, one of the most relevant in the era of personalized medicine, is the non-attention versus women that are few and, also when they are enrolled, sex analysis is lacking. Therefore, in our opinion, it is time to perform more long, extensive and lessheterogeneous trials enrolling both women and men.

Effects of Virgin Olive Oil and Phenol-Enriched Virgin Olive Oils on Lipoprotein Atherogenicity

The atherogenicity of low-density lipoprotein (LDL) and triglyceride-rich lipoproteins (TRLs) may be more significant than LDL cholesterol levels. Clinical trials which have led to increased high-density lipoprotein (HDL) cholesterol have not always seen reductions in cardiovascular disease (CVD). Furthermore, genetic variants predisposing individuals to high HDL cholesterol are not associated with a lower risk of suffering a coronary event, and therefore HDL functionality is considered to be the most relevant aspect. Virgin olive oil (VOO) is thought to play a protective role against CVD. This review describes the effects of VOO and phenol-enriched VOOs on lipoprotein atherogenicity and HDL atheroprotective properties. The studies have demonstrated a decrease in LDL atherogenicity and an increase in the HDL-mediated macrophage cholesterol efflux capacity, HDL antioxidant activity, and HDL anti-inflammatory characteristics after various VOO interventions. Moreover, the expression of cholesterol efflux-related genes was enhanced after exposure to phenol-enriched VOOs in both post-prandial and sustained trials. Improvements in HDL antioxidant properties were also observed after VOO and phenol-enriched VOO interventions. Furthermore, some studies have demonstrated improved characteristics of TRL atherogenicity under postprandial conditions after VOO intake. Large-scale, long-term randomized clinical trials, and Mendelian analyses which assess the lipoprotein state and properties, are required to confirm these results.

Impact on cardiometabolic risk of a weight loss intervention with higher protein from lean red meat: Combined results of 2 randomized controlled trials in obese middle-aged and older adults

BACKGROUND

The recognized benefits of a higher protein diet on muscle mass and strength in older adults are tempered by concerns of the potentially negative cardiometabolic impact of dietary sources of animal protein.

OBJECTIVE

The aim of this study was to explore the cardiometabolic impact of 2 weight reduction diets: a higher protein diet, providing balanced portions of lean beef and pork throughout the day, vs. a diet following the Recommended Daily Allowance level of protein in obese middle-aged and older adults.

METHODS

Data from Measuring Eating, Activity and Strength: Understanding the Response-Using Protein and Protein Optimization in Women Enables Results-Using Protein were combined for the present analysis. Subjects were randomly assigned to a 6-month weight loss diet (500 kcal deficit) and prescribed a Recommended Daily Allowance level of protein (0.8 g protein/kg BW), control group, or a higher level of protein (1.2 g protein/kg BW), protein group. For the protein group, lean, high-quality protein was evenly distributed between meals or balanced throughout the day (30 g protein/meal). The following cardiometabolic markers were quantified by nuclear magnetic resonance spectroscopy: lipids, lipoproteins, GlycA, trimethylamine-N-oxide, betaine, branched-chain amino acids, and lipoprotein insulin resistance index scores.

RESULTS

In both groups (control [n = 27] and protein [n = 53]), there were significant (P ≤ .05) changes from baseline in weight loss (-6.2% and -7.2%), distance walked (+53.1 and +75.0 meters), and fasting plasma glucose (-7.5 and -6.2 mg/dL), respectively. At endpoint, protein group had significantly (P ≤ .05) lower triglycerides (-17.3 mg/dL), large very-low-density lipoprotein particle concentration (VLDL-P; -1.2 nmol/L), total low-density lipoprotein particle concentration (LDL-P; -67.8 nmol/L), small LDL-P (-59.4 nmol/L) and lipoprotein insulin resistance index (-5.9), whereas control group had significantly (P ≤ .05) lower GlycA (-13.1 μmol/L), total VLDL-P (-7.9 nmol/L), and small VLDL-P (-7.0 nmol/L). Differences between groups were observed for small VLDL-P (P = .02) and protein intake (P < .0001).

CONCLUSIONS

These findings suggest that a hypocaloric diet with either traditional (0.8 g/kg BW/d) or higher protein (1.2 g/kg BW/d; predominantly from lean red meat) content improves risk markers of cardiovascular disease and type II diabetes in obese middle-aged and older adults. Both diets were also associated with improved physical function, and neither had an adverse impact on cardiometabolic outcomes.

Impact of different types of olive oil on cardiovascular risk factors: A systematic review and network meta-analysis

BACKGROUND AND AIM

This network meta-analysis (NMA) compares the effects of different types of olive oil (OO) on cardiovascular risk factors.

METHODS AND RESULTS

Literature search was conducted on three electronic databases (Medline, Web of Science, and Cochrane Central).

INCLUSION CRITERIA

Randomized controlled trials (RCTs) (≥3 weeks duration of intervention) comparing at least two of the following types of OO: refined OO (ROO), mixed OO (MOO), low phenolic (extra) virgin OO (LP(E)VOO), and high phenolic (extra) virgin OO (HP(E)VOO). Random-effects NMA was performed for seven outcomes; and surface under the cumulative ranking curve (SUCRA) was estimated, using an analytical approach (P-score). Thirteen RCTs (16 reports) with 611 mainly healthy participants (mean age: 26-70 years) were identified. No differences for total cholesterol, HDL-cholesterol, triacylglycerols, and diastolic blood pressure were observed comparing ROO, MOO, LP(E)VOO and HP(E)VOO. HP(E)VOO slightly reduce LDL-cholesterol (LDL-C) compared to LP(E)VOO (mean difference [MD]: -0.14 mmol/L, 95%-CI: -0.28, -0.01). Both, HP(E)VOO and LP(E)VOO reduces SBP compared to ROO (range of MD: -2.99 to -2.87 mmHg), and HP(E)VOO may improve oxidized LDL-cholesterol (oxLDL-C) compared to ROO (standardized MD: -0.68, 95%-CI: -1.31, -0.04). In secondary analyses, EVOO may reduce oxLDL-C compared to ROO, and a dose-response relationship between higher intakes of phenolic compounds from OO and lower SBP and oxLDL-C values was detected. HP(E)VOO was ranked as best treatment for LDL-C (P-score: 0.83), oxLDL-C (0.88), and SBP (0.75).

CONCLUSIONS

HP(E)VOO may improve some cardiovascular risk factors, however, public health implications are limited by overall low or moderate certainty of evidence.

Binding of Plant Polyphenols to Serum Albumin and LDL: Healthy Implications for Heart Disease

Cardiovascular disease (CVD) is the leading cause of death in industrialized nations. The initiating event in atherosclerosis, or hardening of the arteries, is oxidation of low density lipoprotein (LDL). Binding with serum albumin and LDL of 41 polyphenols (major antioxidants in plant foods) constituting four classes of flavonoids, three types of phenolic acids, and seven polyphenol conjugate metabolites was investigated indirectly by fluorescence quenching and directly by affinity separation/high-performance liquid chromatography (four of the polyphenols). Stern-Volmer plots yielded K values for the two proteins. Polyphenol binding was significantly stronger for albumin than with LDL. K values were highly correlated with the lipophilicity of the polyphenols. The number of polyphenol molecules determined by quenching was ∼1 for both proteins. Direct analysis under saturation conditions yielded from 2 to 13 molecules of polyphenols/LDL particle. Multiple substituent effects on binding were analyzed. Evidence was put forward that binding of polyphenols to these proteins is protective for CVD by multiple mechanisms.

Effects of a diet naturally rich in polyphenols on lipid composition of postprandial lipoproteins in high cardiometabolic risk individuals: an ancillary analysis of a randomized controlled trial

BACKGROUND/OBJECTIVES

Plasma lipoprotein composition, especially in the postprandial state, could be relevant for cardiovascular risk and could be influenced by eating habits. This study evaluated the effects of a polyphenol-rich diet on postprandial lipoprotein composition in individuals at high cardiometabolic risk.

SUBJECTS/METHODS

Seventy-eight individuals with high waist circumference and at least another component of the metabolic syndrome were randomized to either a high-polyphenol (HighP) or low-polyphenol (LowP) diet. Before and after the 8-week intervention, chylomicrons, VLDL1, VLDL2, IDL, LDL, HDL particles, and their lipid concentrations were determined over a 6-h high-fat test meal with high or low-polyphenol content, according to the diet assigned.

RESULTS

VLDL1 postprandial areas under the curve (AUCs) were lower for cholesterol (Chol) (1.48 ± 0.98 vs. 1.91 ± 1.13 mmol/L × 6 h, M ± SD, p = 0.014) and triglycerides (Tg) (4.70 ± 2.70 vs. 6.02 ± 3.07 mmol/L × 6 h, p = 0.005) after the HighP than after the LowP diet, with no changes in Chol/Tg ratio. IDL Chol AUCs were higher after the HighP than after the LowP diet (1.29 ± 0.77 vs. 1.01 ± 0.51 mmol/L × 6 h, p = 0.037). LDL Tg AUCs were higher after the HighP than after the LowP diet (1.15 ± 0.33 vs. 1.02 ± 0.35 mmol/L × 6 h, p < 0.001), with a lower Chol/Tg ratio (14.6 ± 4.0 vs. 16.0 ± 3.8, p = 0.007). HDL Tg AUCs were lower after the HighP than after the LowP diet (1.20 ± 0.41 vs. 1.34 ± 0.37 mmol/L × 6 h, p = 0.013).

CONCLUSIONS

A high-polyphenol diet reduces the postprandial lipid content of large VLDL and increases IDL cholesterol; it modifies the composition of LDL particles-which become richer in triglycerides, and of HDL-which become instead triglyceride poor. The overall changes in atherogenicity by these effects warrant further investigation on clinical cardiovascular outcomes.

Vasculoprotective Role of Olive Oil Compounds via Modulation of Oxidative Stress in Atherosclerosis

Existing evidence supports the significant role of oxidative stress in the endothelial injury, and there is a direct link between increased oxidative stress, and the development of endothelial dysfunction. Endothelial dysfunction precedes the development of atherosclerosis and subsequent cardiovascular disease (CVD). The overproduction of reactive oxygen species facilitates the processes, such as oxidative modification of low-density lipoproteins and phospholipids, reduction in the NOS-derived nitric oxide, and the functional disruption of high-density lipids that are profoundly involved in atherogenesis, inflammation, and thrombus formation in vascular cells. Thus, under oxidative stress conditions, endothelial dysfunction was found to be associated with the following endothelial alterations: reduced nitric oxide bioavailability, increased anticoagulant properties, increased platelet aggregation, increased expression of adhesion molecules, chemokines, and cytokines. In this review, we summarized the evidence indicating that endothelial damage triggered by oxidation can be diminished or reversed by the compounds of olive oil, a readily available antioxidant food source. Olive oil bioactive compounds exhibited a potent capability to attenuate oxidative stress and improve endothelial function through their anti-inflammatory, anti-oxidant, and anti-thrombotic properties, therefore reducing the risk and progression of atherosclerosis. Also, their molecular mechanisms of action were explored to establish the potential preventive and/or therapeutic alternatives to the pharmacological remedies available.

Lipoprotein insulin resistance index, a high-throughput measure of insulin resistance, is associated with incident type II diabetes mellitus in the Prevention of Renal and Vascular End-Stage Disease study

BACKGROUND

Early assessment of insulin resistance may be a way of identifying patients at risk as well as monitoring treatments that increase insulin sensitivity and reduce the risk of developing type II diabetes mellitus (T2DM).

OBJECTIVE

The objective of the study was to evaluate the ability of the Lipoprotein Insulin Resistance Index (LP-IR) to predict incident T2DM in a large cohort.

METHODS

LP-IR scores were calculated using 6 lipoprotein particle concentrations and sizes measured by nuclear magnetic resonance spectroscopy. In total, 5977 nondiabetic men and women were included. Cox proportional hazards regression was used to evaluate the association of LP-IR scores with incident T2DM.

RESULTS

LP-IR scores were closely associated with insulin resistance, assessed by homeostatic model assessment of insulin resistance (r = 0.51; P < .0001). During a median follow-up for 7.5 years, 278 new T2DM cases were ascertained. The Kaplan-Meier plot with log-rank test (P < .001) demonstrated that elevated LP-IR levels are associated with an increased T2DM risk. In analyses adjusted for age and sex, LP-IR was associated with incident T2DM; hazard ratio (HR) for the highest versus lowest quartile was 10.18 (95% confidence interval: 6.24-16.61), P < .0001. After adjustment for clinical risk factors, the HR was attenuated but remained significant (HR 3.02 [1.73-5.25], P < .0001). LP-IR scores added significantly to the performance of the Framingham Offspring prediction algorithm; C-index (95% confidence interval) for the Framingham Offspring score without and with LP-IR (0.863 [0.863-0.864] and 0.868 [0.867-0.86], P < .0001). Similar results were observed when LP-IR was analyzed as a categorical variable with a clinical cut-point of 68.

CONCLUSION

LP-IR may be a convenient way to assess insulin resistance and T2DM risk, as well as to monitor preventative treatments.

Influence of Bioactive Nutrients on the Atherosclerotic Process: A Review

The protective effects of a dietary intervention as a useful tool in the prevention of atherosclerosis disease has gained greater attention in recent years. Several epidemiological studies have demonstrated the importance of diet in reducing expensive treatments or possible undesirable side effects. The main aim of this review is to examine the effects of specific nutrients on the development and progression of atherosclerosis in patients with cardiovascular disease. Various mechanisms have been proposed to explain the cardioprotective effect of different nutrients. In this sense, results have shown stabilization of vulnerable atherosclerotic plaques or downregulation of biomarkers related to inflammation through nutrients such as Omega-3 polyunsaturated fatty acids, hydroxytyrosol of extra virgin olive oil, lycopen, phytosterols of plants, or flavonols of fruits and vegetables, among others. The accumulated evidence on the anti-inflammatory effects related to these nutrients is summarized in the present review.

Significant metabolic improvement by a water extract of olives: animal and human evidence

PURPOSE

Dyslipidemia and impaired glucose metabolism are the main health issues of growing prevalence and significant high healthcare cost, requiring novel prevention and/or therapeutic approaches. Epidemiological and animal studies revealed that olive oil is an important dietary constituent, inducing normolipidemia. However, no studies have specifically investigated the polyphenol-rich water extract of olives (OLWPE), generated during olive oil production.

METHODS

In the present work, we initially examined the effect of OLPWE on animals' metabolic parameters. Rats fed with a high-fat diet were treated with three different doses of OLPWE for 4 months. Additionally, bioavailability was explored. Afterwards, OLWPE's metabolic effect was explored in humans. Healthy volunteers consumed microencapsulated OLWPE for 4 weeks, in a food matrix [one portion (30 g) of a meat product].

RESULTS

High-fat-fed rats developed a metabolic dysfunction, with increased LDL and insulin levels and decreased HDL; this syndrome was significantly impaired when treated with OLWPE. Treated rats had increased total plasma antioxidant capacity, while several phenolic compounds were detected in their blood. These findings were also verified in humans that consumed OLWPE, daily, for 4 weeks. Interestingly, in individuals with elements of cardio-metabolic risk, OLWPE consumption resulted in reduced glucose, insulin, total cholesterol, LDL and oxLDL levels.

CONCLUSIONS

Our data clearly show that OLWPE can improve glucose and lipid profile, indicating its possible use in the design of functional food and/or therapeutic interventions.

Cardiovascular Benefits of Phenol-Enriched Virgin Olive Oils: New Insights from the Virgin Olive Oil and HDL Functionality (VOHF) Study

SCOPE

The main findings of the "Virgin Olive Oil and HDL Functionality" (VOHF) study and other related studies on the effect of phenol-enriched virgin olive oil (VOO) supplementation on cardiovascular disease are integrated in the present work.

METHODS AND RESULTS

VOHF assessed whether VOOs, enriched with their own phenolic compounds (FVOO) or with those from thyme (FVOOT), improve quantity and functionality of HDL. In this randomized, double-blind, crossover, and controlled trial, 33 hypercholesterolemic subjects received a control VOO (80 mg kg-1 ), FVOO (500 mg kg-1 ), and FVOOT (500 mg kg-1 ; 1:1) for 3 weeks. Both functional VOOs promoted cardioprotective changes, modulating HDL proteome, increasing fat-soluble antioxidants, improving HDL subclasses distribution, reducing the lipoprotein insulin resistance index, increasing endogenous antioxidant enzymes, protecting DNA from oxidation, ameliorating endothelial function, and increasing fecal microbial metabolic activity. Additional cardioprotective benefits were observed according to phenol source and content in the phenol-enriched VOOs. These insights support the beneficial effects of OO and PC from different sources.

CONCLUSION

Novel therapeutic strategies should increase HDL-cholesterol levels and enhance HDL functionality. The tailoring of phenol-enriched VOOs is an interesting and useful strategy for enhancing the functional quality of HDL, and thus, it can be used as a complementary tool for the management of hypercholesterolemic individuals.

Effects of Virgin Olive Oils Differing in Their Bioactive Compound Contents on Metabolic Syndrome and Endothelial Functional Risk Biomarkers in Healthy Adults: A Randomized Double-Blind Controlled Trial

The aim of this study was to evaluate the effect of virgin olive oils (VOOs) enriched with phenolic compounds and triterpenes on metabolic syndrome and endothelial function biomarkers in healthy adults. The trial was a three-week randomized, crossover, controlled, double-blind, intervention study involving 58 subjects supplemented with a daily dose (30 mL) of three oils: (1) a VOO (124 ppm of phenolic compounds and 86 ppm of triterpenes); (2) an optimized VOO (OVOO) (490 ppm of phenolic compounds and 86 ppm of triterpenes); and (3) a functional olive oil (FOO) high in phenolic compounds (487 ppm) and enriched with triterpenes (389 ppm). Metabolic syndrome and endothelial function biomarkers were determined in vivo and ex vivo. Plasma high density lipoprotein cholesterol (HDLc) increased after the OVOO intake. Plasma endothelin-1 levels decreased after the intake of the three olive oils, and in blood cell cultures challenged. Daily intake of VOO enriched in phenolic compounds improved plasma HDLc, although no differences were found at the end of the three interventions, while VOO with at least 124 ppm of phenolic compounds, regardless of the triterpenes content improved the systemic endothelin-1 levels in vivo and ex vivo. No effect of triterpenes was observed after three weeks of interventions. Results need to be confirmed in subjects with metabolic syndrome and impaired endothelial function (Clinical Trials number NCT02520739).

Effects of hepato-preferential basal insulin peglispro on nuclear magnetic resonance biomarkers lipoprotein insulin resistance index and GlycA in patients with diabetes

AIM

To characterize the effects of hepato-preferential basal insulin peglispro (BIL) and insulin glargine on insulin resistance (lipoprotein insulin resistance index [LP-IR]) and inflammation (GlycA), and to explore the biological implications.

METHODS

This substudy included 847 patients with Type 1 diabetes (T1D) or Type 2 diabetes (T2D) in four cohorts of the BIL development program. LP-IR and GlycA were measured before and after insulin treatment. Correlations between LP-IR, GlycA, clinical parameters and liver biomarkers were assessed.

RESULTS

LP-IR and GlycA were higher in T2D than T1D. LP-IR increased in patients switched from basal insulins to BIL but not in insulin-naive patients. GlycA decreased in T2D patients treated with BIL and T1D patients treated with glargine.

CONCLUSION

These exploratory analyses help to characterize differences in biological effects between BIL and glargine treatment.

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.

Effects of Olive Oil Phenolic Compounds on Inflammation in the Prevention and Treatment of Coronary Artery Disease

Coronary artery disease (CAD) is responsible for more than 7 million deaths worldwide. In the early stages of the development of atherosclerotic plaques, cardiovascular risk factors stimulate vascular endothelial cells, initiating an inflammatory process, fundamental in the pathogenesis of CAD. The inclusion of potentially cardioprotective foods, such as olive oil, to the diet, may aid in the control of these risk factors, and in the reduction of cytokines and inflammatory markers. The present review aims to address the interaction between phenolic compounds present in olive oil, and inflammation, in the prevention and treatment of CAD. In vitro and in vivo studies suggest that phenolic compounds, such as hydroxytyrosol, tyrosol, and their secoiridoid derivatives, may reduce the expression of adhesion molecules and consequent migration of immune cells, modify the signaling cascade and the transcription network (blocking the signal and expression of the nuclear factor kappa B), inhibit the action of enzymes responsible for the production of eicosanoids, and consequently, decrease circulating levels of inflammatory markers. Daily consumption of olive oil seems to modulate cytokines and inflammatory markers related to CAD in individuals at risk for cardiovascular diseases. However, clinical studies that have evaluated the effects of olive oil and its phenolic compounds on individuals with CAD are still scarce.

Phenol-enriched olive oils modify paraoxonase-related variables: A randomized, crossover, controlled trial

SCOPE

Low paraoxonase (PON)1 activities, and high PON1 and low PON3 protein levels are characteristic of cardiovascular disease. Our aim was to assess short- and long-term effects of virgin olive oils (VOO), enriched with their own phenolic compounds (PC; FVOO) or with them plus complementary PC from thyme (FVOOT), on PON-related variables and the mechanisms involved.

METHODS AND RESULTS

Two randomized, controlled, double-blind, and crossover interventions were conducted. In an acute intake study, participants ingested three FVOOs differing in PC content. In a sustained intake study, participants ingested a control VOO and two different FVOOs with the same PC content but differing in PC source. Acute and sustained intake of VOO and FVOO decreased PON1 protein and increased PON1-associated specific activities, while FVOOT yielded opposite results. PON3 protein levels increased only after sustained consumption of VOO. Mechanistic studies performed in rat livers showed that intake of isolated PC from VOO and from thyme modulate mitogen-activated protein kinases and peroxisome proliferator-activated receptors regulating PON synthesis, while a combination of these PCs cancels such regulation.

CONCLUSION

This study reveals that the intake of phenol-enriched FVOOs modulates oxidative balance by modifying PON-related variables according to PC content and source, and this modulation can be perceived as beneficial.

Protective effect of homovanillyl alcohol on cardiovascular disease and total mortality: virgin olive oil, wine, and catechol-methylation

Background: Hydroxytyrosol is a phenolic compound that is present in virgin olive oil (VOO) and wine. Hydroxytyrosol-related foods have been shown to protect against cardiovascular disease (CVD).Objective: We investigated the associations between hydroxytyrosol and its biological metabolite, 3-O-methyl-hydroxytyrosol, also known as homovanillyl alcohol (HVAL), with CVD and total mortality.Design: We included 1851 men and women with a mean ± SD age of 66.8 ± 6 y at high risk of CVD from prospective cohort data. The primary endpoint was a composite of myocardial infarction, stroke, and death from cardiovascular causes; the secondary endpoint was all-cause mortality. Twenty-four-hour urinary hydroxytyrosol and HVAL and catechol-O-methyltransferase (COMT) rs4680 genotypes were measured.Results: After multivariable adjustment, all biomarkers were associated, as a continuous variable, with lower CVD risk, but only HVAL showed a strong inverse association (HR: 0.44; 95% CI: 0.25, 0.80) for the comparison between quintiles. Only HVAL, as a continuous variable, was associated with total mortality (HR: 0.81; 95% CI: 0.70, 0.95). Individuals in the highest quintile of HVAL compared with the lowest had 9.2 (95% CI: 3.5, 20.8) and 6.3 (95% CI: 2.3, 12.1) additional years of life or years free of CVD, respectively, after 65 y. Individuals with the rs4680GG genotype had the highest HVAL concentrations (P = 0.05). There was no association between COMT genotypes and events or interaction between COMT genotypes and HVAL concentrations.Conclusions: We report, for the first time to our knowledge, an independent association between high urinary HVAL concentrations and a lower risk of CVD and total mortality in elderly individuals. VOO and wine consumption and a high metabolic COMT capacity for methylation are key factors for high HVAL concentrations. The association that stems from our results reinforces the benefits of 2 key components of the Mediterranean diet (wine and VOO). This trial was registered at www.predimed.es as ISRCTN35739639.

State of the Art on Functional Virgin Olive Oils Enriched with Bioactive Compounds and Their Properties

Virgin olive oil, the main fat of the Mediterranean diet, is per se considered as a functional food—as stated by the European Food Safety Authority (EFSA)—due to its content in healthy compounds. The daily intake of endogenous bioactive phenolics from virgin olive oil is variable due to the influence of multiple agronomic and technological factors. Thus, a good strategy to ensure an optimal intake of polyphenols through habitual diet would be to produce enriched virgin olive oil with well-known bioactive polyphenols. Different sources of natural biological active substances can be potentially used to enrich virgin olive oil (e.g., raw materials derived from the same olive tree, mainly olive leaves and pomaces, and/or other compounds from plants and vegetables, mainly herbs and spices). The development of these functional olive oils may help in prevention of chronic diseases (such as cardiovascular diseases, immune frailty, ageing disorders and degenerative diseases) and improving the quality of life for many consumers reducing health care costs. In the present review, the most relevant scientific information related to the development of enriched virgin olive oil and their positive human health effects has been collected and discussed.

The NUTRAOLEOUM Study, a randomized controlled trial, for achieving nutritional added value for olive oils

Background

Virgin olive oil, a recognized healthy food, cannot be consumed in great quantities. We aim to assess in humans whether an optimized virgin olive oil with high phenolic content (OVOO, 429 mg/Kg) and a functional one (FOO), both rich in phenolic compounds (429 mg/Kg) and triterpenic acids (389 mg/kg), could provide health benefits additional to those supplied a by a standard virgin olive oil (VOO).

Methods/design

A randomized, double-blind, crossover, controlled study will be conducted. Healthy volunteers (aged 20 to 50) will be randomized into one of three groups of daily raw olive oil consumption: VOO, OVOO, and FOO (30 mL/d). Olive oils will be administered over 3-week periods preceded by 2-week washout ones. The main outcomes will be markers of lipid and DNA oxidation, inflammation, and vascular damage. A bioavailability and dose-response study will be nested within this sustained- consumption one. It will be made up of 18 volunteers and be performed at two stages after a single dose of each olive oil. Endothelial function and nitric oxide will be assessed at baseline and at 4 h and 6 h after olive oil single dose ingestion.

Discussion

For the first time the NUTRAOLEUM Study will provide first level evidence on the health benefits in vivo in humans of olive oil triterpenes (oleanolic and maslinic acid) in addition to their bioavailability and disposition.

Trial registration

The Trial has been registered in ClinicalTrials.gov ID: NCT02520739.