Comparison of blood lipid-lowering effects of olive oil and other plant oils: A systematic review and meta-analysis of 27 randomized placebo-controlled clinical trials

Mediterranean diet enriched with olive oil shows no consistent benefits on cardiometabolic and anthropometric parameters: a systematic review with meta-analysis of randomized controlled trials

PURPOSE

Cardiovascular disease (CVD) is the primary cause of death worldwide but there is a variation in its burden across some nations that seems to be related to dietary habits. Mediterranean populations have lower rates of morbidity and mortality from CVD. Thus, this systematic review and meta-analysis aimed to assess the impacts of the Mediterranean diet (MedDiet) enriched with olive oil on blood lipids, glycemic indices, blood pressure, and anthropometric indices.

METHODS

A comprehensive search of the Web of Science, PubMed (MEDLINE), Scopus, Cochrane Library, Google Scholar, Embase, and CINAHL databases until March 2024 was conducted to identify clinical trials studying the effects of MedDiet enriched with olive oil on the aforementioned parameters.

RESULTS

In total, 3303 records were retrieved. A total of 18 clinical trials met the inclusion criteria after records were screened for eligibility. According to the pooled analysis from the random-effects model, the MedDiet enriched with olive oil significantly reduced triglycerides (TG) compared with the control group (WMD = -2.40 mg/dl; 95%CI, -4.533 to -0.262; P = 0.027). Strong heterogeneity was observed. Sensitivity analysis did not change our results and no significant effect of any trial on the overall effect sizes of all variables were found. There was a concern about the reporting bias for some studies which reported some main outcomes.

CONCLUSION

MedDiet enriched with olive oil showed no consistent effects on any of the reported markers of cardiovascular health except on TG.

SYSTEMATIC REVIEW REGISTRATION

CRD42023424641.

Health Effects of Various Edible Vegetable Oil: An Umbrella Review

Vegetable oils, derived from diverse sources such as seeds, nuts, and some fruits, play a significant role in dietary health. However, the current evidence on the health effects of different types of vegetable oil consumption remains controversial. This umbrella review aims to synthesize evidence from systematic reviews and meta-analyses to assess the health outcomes associated with various vegetable oils. A comprehensive literature search was performed up to 31 July, 2023 on 12 databases for studies examining the association of different vegetable oils with health outcomes in adults. Data was extracted independently by 2 authors, with evidence strength assessed using the grading of recommendations, assessment, development, and evaluation criteria. A total of 48 studies, including 206 meta-analyses, were included. Moderate to very low certainty evidence showed that monounsaturated and polyunsaturated fatty acids such as canola oil, virgin olive oil, and rice bran oil are beneficial in reducing serum total cholesterol and low-density lipoprotein (LDL) concentrations. Conversely, low to very low certainty evidence suggests that oils high in saturated fats, such as coconut oil and palm oil, increase total cholesterol and LDL concentrations but also raise high-density lipoprotein concentrations. Very low certainty evidence showed the consumption of olive oil, sesame oil, and coconut oil could improve blood sugar control. Low certainty evidence showed olive oil consumption reduced risk of breast, digestive, and other cancers. Moderate to very low certainty evidence suggested that canola oil and sesame oil consumption reduced body weight. The consumption of vegetable oil appears to offer different health benefits, with summary estimates indicating beneficial effects on reducing lipid concentrations, especially with monounsaturated and polyunsaturated rich oils when consumed in recommended amounts. Future research should focus on long-term studies and comprehensive dietary assessments to better understand the health impacts of vegetable oils, providing a basis for informed dietary recommendations. This study was registered at PROSPERO as CRD42021239210.

Health Outcomes Associated with Olive Oil Intake: An Umbrella Review of Meta-Analyses

Several studies suggested a negative association between olive oil (OO) consumption and the risk of several chronic diseases. However, an attempt to systematically search, organize, and evaluate the existing evidence on all health outcomes associated with OO consumption is lacking. The objective of this review is to describe the multiple health outcomes associated with OO consumption. The Medline, Scopus, and Web of Science databases were searched through 5 April 2024. The selected studies met all of the following criteria: (1) a meta-analysis of both observational (case-control and cohort studies) and interventional studies (trials), (2) an evaluation of the association between OO consumption, mortality, and/or the incidence of non-communicable/chronic degenerative diseases, and (3) a study population ≥18 years old. Two independent reviewers extracted the relevant data and assessed the risk of bias of individual studies. The PRISMA statement and guidelines for the Integration of Evidence from Multiple Meta-Analyses were followed. The literature search identified 723 articles. After selection, 31 articles were included in this umbrella review. The primary health benefits of OO were observed in cardiovascular diseases and risk factors, cancer, mortality, diabetes, and specific biomarkers related to anthropometric status and inflammation. As a key component of the Mediterranean diet, OO can be considered a healthy dietary choice for improving positive health outcomes.

The effect of cottonseed oil on lipids/lipoproteins: a systematic review and plasma cholesterol predictive equations estimations

CONTEXT

Cottonseed oil (CSO) is higher in polyunsaturated fatty acids (PUFA) and saturated fatty acids (SFAs) than many liquid plant oils.

OBJECTIVES

To conduct a systematic review of randomized controlled trials (RCTs) examining effects of CSO on markers of lipid metabolism and evaluate lipid and lipoprotein effects of incorporating CSO into a healthy dietary pattern using regression equations.

DATA SOURCES

A systematic search was conducted for RCTs comparing CSO with a non-CSO comparator in any population.

DATA ANALYSES

The Katan regression equation was used to predict lipid/lipoprotein changes when incorporating CSO into a US-style healthy eating pattern at 25 to 100% of the total oil allowance (ie, 27 g/2000 kcal) compared with average American intake (NHANES 2017 to 2020 pre-COVID pandemic).

RESULTS

In total, 3 eligible publications (n = 2 trials), with 58 participants that provided 44% and 30% of total energy as CSO, were included. Fasting low-density lipoprotein cholesterol (LDL-C; ≈ -7.7 mg/dL) and triglycerides (≈ -7.5 mg/dL) were lower after 5 days of a CSO-enriched diet vs olive oil (OO). In a 56-day trial, CSO lowered total cholesterol (TC; ≈ -14.8 mg/dL), LDL-C (≈ -14.0 mg/dL), and non-high-density lipoprotein cholesterol (≈ -14.2 mg/dL) vs OO. Postprandially, angiopoietin-like protein-3, -4, and -8 concentrations decreased with CSO and increased with OO intake. Compared with average American intake, a healthy eating pattern with 27 g of CSO was estimated to lower TC (-8.1 mg/dL) and LDL-C (-7.3 mg/dL) levels, with minimal reduction in high-density lipoprotein cholesterol (-1.1 mg/dL). Compared with the healthy eating pattern, incorporating 27 g of CSO was predicted to increase TC and LDL-C levels by 2.4 mg/dL.

CONCLUSION

Limited high-quality research suggests CSO may improve lipid/lipoprotein levels compared with OO. Cholesterol predictive equations suggest CSO can be incorporated into a healthy dietary pattern without significantly affecting lipids/lipoproteins.

Olive Oil Consumption, Risk Factors, and Diseases: An Umbrella Review

CONTEXT

Olive oil is a vegetable oil that provides health benefits, including a reduction in free radicals and total cholesterol and prevention of chronic diseases. The escalating incidence of chronic diseases presents a substantial challenge to public health, prompting numerous studies to assess these health-related effects. Despite several systematic reviews and meta-analyses summarizing the association between olive oil consumption and specific health outcomes, there is no summary of the accumulated evidence from these reviews.

OBJECTIVE

This umbrella review summarizes the evidence on olive oil consumption or intervention in adults and its association with multiple risk factors and diseases.

DATA SOURCES

We retrieved systematic reviews of randomized trials or observational studies on oral interventions or the consumption of olive oil. The systematic search encompassed databases including MEDLINE, Embase, Scopus, Web of Science, LILACS, and CENTRAL from inception to February 6, 2023.

DATA EXTRACTION

Two independent reviewers conducted data extraction and assessed methodological quality using the Joanna Briggs Institute tool.

DATA ANALYSIS

Overall, 17 systematic reviews of randomized trials and observational studies, covering outcomes such as cardiovascular diseases, cancer, type 2 diabetes, glucose metabolism, inflammatory and oxidative markers, and all-cause mortality, were included. The evidence suggests a beneficial association between olive oil consumption and cardiovascular diseases, cancer, type 2 diabetes, and all-cause mortality. However, the evidence was less definitive for inflammatory markers, oxidative stress, glucose metabolism, and blood lipid outcomes. Several meta-analyses revealed high heterogeneity and wide confidence intervals, along with a limited number of randomized clinical trials.

CONCLUSION

Given the high heterogeneity and low quality of evidence, further studies involving randomized trials are imperative. Prioritizing an in-depth analysis of specific olive oil components and using a control group with distinct characteristics and different effects is strongly recommended.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022357290.

Fats and oils - a scoping review for Nordic Nutrition Recommendations 2023

This scoping review for the Nordic Nutrition Recommendations 2023 summarizes the available evidence on fats and oils from a food level perspective. A literature search for systematic reviews (SRs) and meta-analyses was conducted in PubMed. There are few SRs and meta-analyses available that investigate the association between fats and oils (food level) and health outcomes; the majority report associations at the nutrient level (fatty acid classes). All identified SRs and meta-analyses were of low methodological quality, thus the findings and conclusions presented within this scoping review should be interpreted cautiously. Based on this limited evidence, the following results were indicated: the intake of olive oil may be associated with reduced risk of cardiovascular disease (CVD), type 2 diabetes (T2D), and total mortality in prospective cohort studies. The intake of butter was not associated with the risk of CVD but may be related to slightly lower risk of T2D and higher risk of total mortality in prospective cohort studies. For cancer, the evidence is sparse and primarily based on case-control studies. The intake of olive oil may be associated with reduced risk of cancer, whereas the intake of butter may be associated with increased risk of certain cancer types. Butter increases LDL-cholesterol when compared to virtually all other fats and oils. Palm oil may increase LDL-cholesterol when compared to oils rich in MUFA or PUFA but may not have any effect on glucose or insulin. Coconut oil may increase LDL-cholesterol when compared to other plant oils but may decrease LDL-cholesterol when compared to animal fats rich in SFA. Canola/rapeseed oil may decrease LDL-cholesterol compared to olive oil, sunflower oil and sources of SFA and may also reduce body weight compared to other oils. Olive oil may decrease some inflammation markers but may not have a differential effect on LDL-cholesterol compared to other fats and oils. The effect on risk markers likely differs depending on the type/version of oil, for example, due to the presence of polyphenols, phytosterols and other minor components. Taken together, based on the available evidence, oils rich in unsaturated fat (e.g. olive oil, canola oil) are to be preferred over oils and fats rich in saturated fat (e.g. butter, tropical oils).

Comparison of fish oil supplements and corn oil effects on serum lipid profile: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The present study aimed to investigate the effects of fish oil supplements compared to corn oil on serum lipid profiles by performing a meta-analysis of randomized controlled trials (RCTs).

METHODS

Online databases including PubMed, Web of Science, and Scopus were searched until 30 December 2022. Pooled effect sizes were reported as the weighted mean difference (WMD) with 95% confidence intervals (CI). The Cochrane Collaboration's risk-of-bias tool was utilized to evaluate the quality of the studies. Lipid parameters, including triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL), were assessed in the meta-analysis.

RESULTS

Overall, 16 eligible trials were included in this systematic review and meta-analysis. The results revealed that the fish oil supplements significantly reduced TG (WMD: - 25.50 mg/dl, 95% CI: - 42.44, - 8.57, P = 0.000) levels compared to corn oil. Also, in this study, fish oil supplements had a positive and significant effect on HDL (WMD: 2.54 mg/dl, 95% CI: 0.55, 4.52). There were no significant changes in TC and LDL.

CONCLUSIONS

Our findings showed the effects of fish oil supplements on reducing TG and increasing HDL-c compared to corn oil. Further larger and well-designed RCTs are required to confirm these data.

Effect of Extra Virgin Olive Oil on Anthropometric Indices, Inflammatory and Cardiometabolic Markers: a Systematic Review and Meta-Analysis of Randomized Clinical Trials

BACKGROUND

A large body of literature associated extra virgin olive oil (EVOO) consumption with low risk of cardiovascular disease and mortality. However, findings from clinical trials related to EVOO consumption on blood pressure, lipid profile, and anthropometric and inflammation parameters are not univocal.

OBJECTIVES

The aim of this systematic review and meta-analysis was to evaluate the effect of EVOO consumption on cardiometabolic risk factors and inflammatory mediators.

METHODS

We searched PubMed/MEDLINE, Scopus, and Cochrane up through 31 March, 2023, without any particular language limitations, in order to identify randomized controlled trials (RCTs) that examined the effects of EVOO consumption on cardiometabolic risk factors, inflammatory mediators, and anthropometric indices. Outcomes were summarized as standardized mean difference (SMD) with 95% confidence intervals (CIs) estimated from Hedge's g and random-effects modeling. Heterogeneity was assessed by Cochran Q-statistic and quantified (I2).

RESULTS

Thirty-three trials involving 2020 participants were included. EVOO consumption was associated with a significant decrease in insulin (n = 10; SMD: -0.28; 95% CI: -0.51, -0.05; I2 = 48.57%) and homeostasis model assessment of insulin resistance levels (HOMA-IR) (n = 9; SMD: -0.19; 95% CI: -0.35, -0.03; I2 = 00.00%). This meta-analysis indicated no significant effect of consuming EVOO on fasting blood glucose, triglycerides, total cholesterol, low density lipoproteins, very low density lipoproteins, high density lipoproteins, Apolipoprotein (Apo) A-I and B, lipoprotein a, blood pressure, body mass index, waist circumference, waist to hip ratio, C-reactive protein, interleukin-6, interleukin-10, and tumor necrosis factor α levels (P > 0.05).

CONCLUSIONS

The present evidence supports a beneficial effect of EVOO consumption on serum insulin levels and HOMA-IR. However, larger well-designed RCTs are still required to evaluate the effect of EVOO on cardiometabolic risk biomarkers. This study was registered in PROSPERO as CRD42023409125.

Use of Olives-derived Phytochemicals for Prevention and Treatment of Atherosclerosis: An Update

Mediterranean diet is frequently associated with longevity and a lower incidence of adverse cardiovascular events because of the biological activities and health effects of olives - its key component. Olive oil, olive leaf extract, fruits and different by-products contain many bioactive components that exert anti-oxidant, anti-inflammatory and anti-apoptotic activities. In this review, we focus on the recent studies exploring molecular mechanisms underlying the cardioprotective properties of different olive oils, olive leave extracts, and specific micro-constituents (such as oleuropein, tyrosol, hydroxytyrosol and others) in vitro on rodent models and in clinical trials on human subjects. Particularly, hydroxytyrosol and oleuropein were identified as the major bioactive compounds responsible for the antioxidant, anti-inflammatory, anti-platelet aggregation and anti-atherogenic activities of olive oil. In total, the discussed results demonstrated a positive association between the consumption of olive oil and improvement in outcomes in atherosclerosis, diabetes, myocardial infarction, heart failure, hypertension and obesity.

Comparison of canola oil and olive oil consumption on the serum lipid profile in adults: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Several randomized clinical trials have investigated the effects of canola oil (CO) compared to olive oil (OO) on the serum lipid profiles in adults. However, the results of these studies are inconsistent. Thus, this study aimed to assess the comparison of CO and OO consumption on the serum lipid components in adults.

METHODS AND RESULTS

The following online databases were searched until February 4th, 2022: PubMed/Medline, Scopus, Clarivate Analytics Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar. The effect sizes were stated as the weighted mean difference (WMD) with 95% confidence intervals (CI). A total of 13 eligible trials were included in this meta-analysis. The results showed that the CO consumption, significantly reduced serum LDL-c (WMD: -6.13 mg/dl, 95%CI: -9.79, -2.46, p = 0.001), TC (WMD: -8.92 mg/dl, 95% CI: -13.52, -4.33, P < 0.001) and LDL-c/HDL-c ratio (WMD: -0.30; 95% CI, -0.53, -0.06, p = 0.01) levels compared to OO. There were no significant changes in the other components of the blood lipids.

CONCLUSION

The results of this review suggest that CO consumptionhas beneficial effects on LDL-c, TC, and LDL-c/HDL-c ratio compared to OO. Therefore, its replacement with OO can have cardioprotective impacts.

Effects of Dietary Linoleic Acid on Blood Lipid Profiles: A Systematic Review and Meta-Analysis of 40 Randomized Controlled Trials

Th aim of this meta-analysis was to elucidate whether dietary linoleic acid (LA) supplementation affected blood lipid profiles, including triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), compared with other fatty acids. Embase, PubMed, Web of Science and the Cochrane Library databases, updated to December 2022, were searched. The present study employed weighted mean difference (WMD) and a 95% confidence interval (CI) to examine the efficacy of the intervention. Out of the 3700 studies identified, a total of 40 randomized controlled trials (RCTs), comprising 2175 participants, met the eligibility criteria. Compared with the control group, the dietary intake of LA significantly decreased the concentrations of LDL-C (WMD: -3.26 mg/dL, 95% CI: -5.78, -0.74, I² = 68.8%, p = 0.01), and HDL-C (WMD: -0.64 mg/dL, 95% CI: -1.23, -0.06, I² = 30.3%, p = 0.03). There was no significant change in the TG and TC concentrations. Subgroup analysis showed that the LA intake was significantly reduced in blood lipid profiles compared with saturated fatty acids. The effect of LA on lipids was not found to be dependent on the timing of supplementation. LA supplementation in an excess of 20 g/d could be an effective dose for lowering lipid profiles. The research results provide further evidence that LA intake may play a role in reducing LDL-C and HDL-C, but not TG and TC.

Effects of camelina oil supplementation on lipid profile and glycemic control: a systematic review and dose‒response meta-analysis of randomized clinical trials

BACKGROUND

This systematic review and dose-response meta-analysis of published randomized controlled trials (RCTs) was conducted to determine the effectiveness of camelina oil supplementation (COS) on lipid profiles and glycemic indices.

METHODS

Relevant RCTs were selected by searching the ISI Web of Science, PubMed, and Scopus databases up to July 1, 2022. RTCs with an intervention duration of less than 2 weeks, without a placebo group, and those that used COS in combination with another supplement were excluded. Weighted mean differences and 95% confidence intervals were pooled by applying a random-effects model, while validated methods examined sensitivity analyses, heterogeneity, and publication bias.

RESULTS

Seven eligible RCTs, including 428 individuals, were selected. The pooled analysis revealed that COS significantly improved total cholesterol in studies lasting more than 8 weeks and utilizing dosages lower than 30 g/d compared to the placebo group. The results of fractional polynomial modeling indicated that there were nonlinear dose-response relations between the dose of COS and absolute mean differences in low-density cholesterol, high-density cholesterol, and total cholesterol, but not triglycerides. It appears that the greatest effect of COS oil occurs at the dosage of 20 g/day.

CONCLUSION

The present meta-analysis indicates that COS may reduce cardiovascular disease risk by improving lipid profile markers. Based on the results of this study, COS at dosages lower than 30 g/d may be a beneficial nonpharmacological strategy for lipid control. Further RCTs with longer COS durations are warranted to expand on these results.

Preferences for dietary oils and fats in cooking and food preparation methods: a cross-sectional analysis of Australian adults

Dietary oils and fats contain different fatty acid compositions that are associated with cardiometabolic disease risk. Despite their influence on disease outcomes, the types of dietary oils and fats predominately used in Australian households remain unknown. The aim of this study was to investigate the use of dietary oils and fats in cooking and food preparation in Australia. Adults living in Australia completed a cross-sectional online survey outlining their current household oil and fat use from July to December 2021. The survey was disseminated via social media platforms and included questions about the types of dietary oils and fats used for different cooking methods and the perceived motivators for choosing the main household oil. A total of 1248 participants responded to the survey. Participants were mostly female (91·6 %) aged between 25 and 44 years (56·7 %). The majority of participants (84·5 %) reported using some form of olive oil as their main source of oil for cooking and food preparation. Almost two-thirds of the sample (65·4 %) reported using extra virgin olive oil (EVOO), mainly in raw food preparation (71·5 %) or savoury baking and roasting (58 %). Fewer households reported using rice bran oil (4·6 %), canola oil (4·3 %) and vegetable oil (1·8 %). Almost half of all participants (49·6 %) identified perceived health benefits as the primary motivating factor for their main choice of oil, followed by sensory preference (46·7 %), versatility (10·2 %) and convenience (8·8 %). Australian adults frequently use olive oil, specifically EVOO, as the main oil for cooking and food preparation in the household.

The effects of olive oil consumption on blood lipids: a systematic review and dose-response meta-analysis of randomised controlled trials

We performed a systematic review and dose-response meta-analysis of randomised trials on the effects of olive oil consumption on blood lipids in adults. A systematic search was performed in PubMed, Scopus and Web of Science databases until May 2021. Randomised controlled trials (RCT) evaluating the effect of olive oil intake on serum total cholesterol (TC), TAG, LDL-cholesterol and HDL-cholesterol in adults were included. The mean difference (MD) and 95 % CI were calculated for each 10 g/d increment in olive oil intake using a random-effects model. A total of thirty-four RCT with 1730 participants were included. Each 10 g/d increase in olive oil consumption had minimal effects on blood lipids including TC (MD: 0·79 mg/dl; 95 % CI (-0·08, 1·66); I² = 57 %; n 31, GRADE = low certainty), LDL-cholesterol (MD: 0·04 mg/dl, 95 % CI (-1·01, 0·94); I² = 80 %; n 31, GRADE = very low certainty), HDL-cholesterol (MD: 0·22 mg/dl; 95 % CI (-0·01, 0·45); I² = 38 %; n 33, GRADE = low certainty) and TAG (MD: 0·39 mg/dl; 95 % CI (-0·33, 1·11); I² = 7 %; n 32, GRADE = low certainty). Levels of TC increased slightly with the increase in olive oil consumption up to 30 g/d (MD_{30 g/d}: 2·76 mg/dl, 95 % CI (0·01, 5·51)) and then appeared to plateau with a slight downward curve. A trivial non-linear dose-dependent increment was seen for HDL-cholesterol, with the greatest increment at 20 g/d (MD_{20 g/d}: 1·03 mg/dl, 95 % CI (-1·23, 3·29)). Based on existing evidence, olive oil consumption had trivial effects on levels of serum lipids in adults. More large-scale randomized trials are needed to present more reliable results.

Blood Lipid Responses to Diets Enriched with Cottonseed Oil Compared With Olive Oil in Adults with High Cholesterol in a Randomized Trial

BACKGROUND

Increasing unsaturated fat intake is beneficial for cardiovascular health, but the type of unsaturated fat to recommend remains equivocal.

OBJECTIVES

We investigated the effects of an 8-week diet intervention that was rich in either cottonseed oil (CSO; PUFA rich) or olive oil (OO; MUFA rich) on blood lipids in hypercholesterolemic adults.

METHODS

Forty-three men and women with hypercholesterolemia (53 ± 10 years; BMI, 27.6 ± 4.8 kg/m2) completed this randomized parallel clinical trial consisting of an 8-week partial outpatient feeding intervention. Participants were given meals and snacks accounting for ∼60% of their daily energy needs, with 30% of energy needs from either CSO (n = 21) or OO (n = 22). At pre- and postdiet intervention visits, participants consumed a high-SFA meal (35% of total energy needs; 70% of energy from fat). The primary outcomes of fasting cholesterol profiles and secondary outcomes of postprandial blood lipids and glycemic markers were assessed over a 5-hour period.

RESULTS

There were greater reductions from baseline to week 8 in fasting serum total cholesterol (TC; -17.0 ± 3.94 mg/dL compared with -2.18 ± 3.72 mg/dL, respectively; P = 0.008), LDL cholesterol (-19.7 ± 3.94 mg/dL compared with -5.72 ± 4.23 mg/dL, respectively; P = 0.018), non-HDL cholesterol (-20.8 mg/dL ± 4.00 compared with -6.61 ± 4.01 mg/dL, respectively; P = 0.014), and apoB (-11.8 mg/dL ± 2.37 compared with -3.10 ± 2.99 mg/dL, respectively; P = 0.05), in CSO compared with OO. There were also visit effects from baseline to week 8 for increases in HDL cholesterol (CSO, 56.5 ± 2.79 mg/dL to 60.2 ± 3.35 mg/dL, respectively; OO: 59.7 ± 2.63 mg/dL to 64.1 ± 2.24 mg/dL, respectively; P < 0.001), and decreases in the TC:HDL-cholesterol ratio (CSO, 4.30 ± 0.27 mg/dL to 3.78 ± 0.27 mg/dL, respectively; OO, 3.94 ± 0.16 mg/dL to 3.57 ± 0.11 mg/dL, respectively; P < 0.001), regardless of group assignment. In response to the high-SFA meal, there were differences in postprandial plasma glucose (P = 0.003) and triglyceride (P = 0.004) responses and a trend in nonesterified fatty acids (P = 0.11) between groups, showing protection in the postprandial state from an occasional high-SFA fat meal with CSO, but not OO, diet enrichment.

CONCLUSIONS

CSO, but not OO, diet enrichment caused substantial improvements in fasting and postprandial blood lipids and postprandial glycemia in hypercholesterolemic adults. This trial was registered at clinicaltrials.gov as NCT04397055.

No evidence of differential impact of sunflower and rapeseed oil on biomarkers of coronary artery disease or chronic kidney disease in healthy adults with overweight and obesity: result from a randomised control trial

Purpose

The perceived benefits and risks associated with seed oil intake remain controversial, with a limited number of studies investigating the impact of intake on a range of compounds used as cardiometabolic markers. This study aimed to explore the proteomic and cardiometabolic effects of commonly consumed seed oils in the UK, with different fatty acid profiles.

Methods

In a parallel randomised control design, healthy adults (n = 84), aged 25–72 with overweight or obesity were randomised to one of three groups: control (habitual diet, CON); 20 mL rapeseed oil per day (RO), or 20 mL sunflower oil per day (SO). Blood, spot urine and anthropometric measures were obtained at 0, 6 and 12 weeks. Proteomic biomarkers analysis was conducted for coronary arterial disease (CAD) and chronic kidney disease (CKD) using capillary electrophoresis coupled to mass spectrometry (CE-MS). Blood lipids, fasting blood glucose, glycative/oxidative stress and inflammatory markers were also analysed.

Results

No differences in change between time points were observed between groups for CAD or CKD peptide fingerprint scores. No change was detected within groups for CAD or CKD scores. No detectable differences were observed between groups at week 6 or 12 for the secondary outcomes, except median 8-isoprostane, ~ 50% higher in the SO group after 12-weeks compared to RO and CON groups (p = 0.03).

Conclusion

The replacement of habitual fat with either RO or SO for 12 weeks does not lead to an improvement or worsening in cardiovascular health markers in people with overweight or obesity.

Trial registration

Trial registration clinicaltrials.gov NCT04867629, retrospectively registered 30/04/2021.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-022-02810-5.

Effect of Dietary Palm Kernel Oil on the Quality, Fatty Acid Profile, and Sensorial Attributes of Young Bull Meat

Lipid supplementation through vegetable oils in diets for ruminants can be a nutritional strategy to increase energy density, manipulate ruminal fermentation and change the physicochemical composition and sensorial properties of meat. This study evaluated the optimal dietary inclusion of palm kernel oil (PKO) for Nellore bulls on meat quality. The diets consisted of 0.0, 11.5, 23.0, and 34.6 g/kg dry matter (DM) PKO levels. PKO inclusion did not influence the centesimal composition, pH, color indices, water holding capacity, cooking loss, or shear force of the beef. There were linear increases in the concentrations of lauric acid (C12:0) and myristic acid (C14:0) in the bull's meat. However, palmitic acid (C16:0), oleic acid (C18:0), vaccenic acid (t-11-C18:1) and conjugated linoleic acid (CLA), ∑n - 6, ∑n - 3, ∑n - 6/∑n 3, the hypocholesterolemic: hypercholesterolemic ratio of the fatty acid content, and the thrombogenicity index were not affected. There were linear reductions in the oleic acid meat concentration (c-9-C18:1) and elongated enzymatic activity when PKO was added to the bull diet. The atherogenicity index increased linearly due to PKO inclusion in the bull diet. No effect of the inclusion of PKO on meat flavor, perception of tenderness, juiciness, or global acceptance from the sensorial evaluation was recorded. The inclusion of PKO up to 34.6 g/kg DM can be recommended to supplement young bulls with no effects on meat composition and quality characteristics.

Healthy diet, depression and quality of life: A narrative review of biological mechanisms and primary prevention opportunities

Unipolar depressive disorder (UDD) affects more than 264 million people worldwide and was projected well before the severe acute respiratory syndrome coronavirus 2 pandemic to be the leading cause of disability-adjusted life years lost in 2030. It is imperative for leading economies to implement preventive strategies targeted towards UDD, given consistent policies are currently lacking. Recently established similarities between the aetiological hypotheses of depression and cardiometabolic diseases are shifting paradigms within this field. It is believed that dietary practices could potentially reduce the incidence of depression; similar to their effects on metabolism. Thus, the aim of this review was to compile current evidence on healthy dietary patterns as suitable contributors towards primary prevention strategies against UDD. Most of the well-known biological mechanisms behind depression have been positively associated with healthful diets and dietary patterns to varying degrees. Interestingly, a common factor of UDD is the production and overall effects of inflammatory cytokines, such as interleukin-6, tumor necrosis factor-α, and C-reactive protein. These compounds have been associated with depressive symptoms, disturbances in neuroendocrine function, leaky gut, monoamine activity and brain function, while also being key factors in the development of cardiometabolic diseases. The Mediterranean diet (MD) in particular, is well supported by first-level evidence regarding its preventive qualities against metabolic and cardiovascular diseases and thus considered a model for healthy eating by various organizations. In one of the few clinical trials investigating these associations, the PREDIMED trial, individuals with diabetes assigned to a MD supplemented with mixed tree nuts experienced a 41% relative risk reduction for developing depression. Lastly, there is a need to include health related quality of life as an indicator of physical and mental well-being, considering its putative associations with depression and suicide risk. Going forward, focusing on clinical trials, using precise nutritional assessments, and identifying nutritional biomarkers which may be related to depression are needed to fully support the implementation of dietary recommendations in the field of psychiatry.

Alleviation of Malathion Toxicity Effect by Coffea arabica L. Oil and Olea europaea L. Oil on Lipid Profile: Physiological and In Silico Study

The community health plans commonly use malathion (MAL), an organophosphate pesticide (OP), to eliminate pathogenic insects. The objective of the present research is to evaluate the consequences of Coffea arabica L. oil and Olea europaea L. oil on MAL-intoxicated male rats. Six equal groups of animals were used for conducting this study (n = 10). Animals in group one were designated as control, animals belonging to group two were exposed to MAL in the measure of hundred mg per kg BW (body weight) for forty-nine days (seven weeks), rats in the third and fourth groups were administered with 400 mg/kg BW of Coffea arabica L. and Olea europaea L. oils, respectively, and the same amount of MAL as given to the second group. Groups five and six were administered with the same amount of Coffea arabica L. oil and Olea europaea L. oil as given to group three. Exposure of rats to 100 mg/kg body weight of MAL resulted in statistical alteration of the serum lipid profile. A marked decline was noticed in the severe changes of these blood parameters when MAL-intoxicated rats were treated with Coffea arabica L. oil and Olea europaea L. oil. Two compounds from Coffea arabica L. oil (Chlorogenic acid) and Olea europaea L. oil (Oleuropein) demonstrated good interaction with xanthine oxidase (XO) and 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) enzymes that are associated with cholesterol production. The present study indicated that Coffea arabica L. oil and Olea europaea L. oil could be considered prospective and potential healing agents against metabolic conditions induced by MAL.

Mediterranean Diet Adherence and Nutritional Status in Dalmatian Kidney Transplant Recipients-Are They Related?

The aim of this study was to evaluate adherence to Mediterranean diet (MeDi) and possible correlation of MeDi adherence and nutritional status parameters in Dalmatian kidney transplant recipients (KTRs). One hundred and sixteen KTRs were included in this study. Data about Mediterranean Diet Serving Score (MDSS), body mass composition, anthropometric parameters, clinical and laboratory parameters were collected for each study participant. The results showed 25% adherence to the MeDi in Dalmatian KTRs. MDSS showed association with higher serum albumin and phosphorus level and higher skeletal muscle mass. Also, significant association between diabetic status and MDSS was found. Adherence to olive oil intake suggested by the MeDi showed significant association with lower level of triglycerides and adherence to nuts suggestions was associated with lower level of fat mass. Following MeDi recommendations for consumption of other foods (cereals, potato, eggs, vegetables, fruits and dairy) were also associated with body mass composition parameters and laboratory findings. In conclusion, low adherence to the MeDi in Dalmatian KTRs raises high concerns. The results showed that MeDi can have favorable effects on nutritional status in KTRs. A structured nutritional approach is needed to enhance adherence to the MeDi and prevent possible adverse effects in this patient population.

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.

Targeting dyslipidemia by herbal medicines: A systematic review of meta-analyses

ETHNOPHARMACOLOGICAL RELEVANCE

The worldwide increasing prevalence of dyslipidemia has become a global health concern. Various herbal remedies have been claimed to be effective for the treatment of dyslipidemia in traditional and folkloric medicine of different regions clinical trials have been conducted to investigate their efficacy. The aim of the current systematic review is to critically assess the meta-analyses of controlled trials (CT) evaluated herb medicines for dyslipidemia.

MATERIALS AND METHODS

Relevant studies from Web of Science, PubMed, Scopus, and Cochrane Library databases based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist until January 2021 have been searched. All meta-analyses which pooled studies on the effect of herbal medicines on lipid profile including total cholesterol (TC), triglyceride (TG), and low- or high-density lipoprotein cholesterol (LDL-C, HDL-C) were also included. Meta-analyses of in vitro, animal or observational studies were excluded.

RESULTS

The overall of 141 meta-analyses were revealed. Vegetable oils, phytosterols, tea, soy protein, nuts, and curcumin have been studied frequently among the herbal medicines. Among 13 meta-analyses on vegetable oils, the greater reduce of TC (18.95 mg/dl), LDL-C (16.24 mg/dl) and TG (13.69 mg/dl) were exhibited from sunflower oil. Furthermore, rice bran oil (6.65 mg/dl) increased HDL-C significantly. Phytosterols in 12 meta-analyses demonstrated significant improvements in reducing TC, LDL-C and TG as 16.4, 23.7, and 8.85 mg/dl, respectively, and rise in HDL-C as 10.6 mg/dl. The highest reduction in serum level of TC, LDL-C and TG was reported while intake Green tea; 27.57, 24.75, and 31.87 mg/dl, accordingly within 9 meta-analyses. Average improvement of lipid profiles by 6 meta-analyses on plant proteins were 23.2, 21.7, 15.06, and 1.55 mg/dl for TC, LDL-C, TG, and HDL-C, respectively. Among 11 meta-analyses on nuts, almond showed better and significant alleviations in TC (10.69 mg/dl), walnut in LDL-C (9.23 mg/dl), pistachio in TG (22.14 mg/dl), and peanut in HDL-C (2.72 mg/dl). Overall, Curcumin, Curcuminoid, and Turmeric have resulted in the reduction of TC (25.13 mg/dl), LDL-C (39.83 mg/dl), TG (33.65 mg/dl), and an increase in the HDL-C (4.31 mg/dl).

CONCLUSION

The current systematic review shed light on the use of herbal medicines for the management of dyslipidemia. However, more well-conducted CTs are required to determine effective doses of herbal medicines.

Effect of combined lipid-lowering and antioxidant nutraceutical on plasma lipids, endothelial function, and estimated cardiovascular disease risk in moderately hypercholesterolemic patients: a double-blind, placebo-controlled randomized clinical trial

INTRODUCTION

Nutraceuticals are a good means to lower cardiovascular risk. Having established a reasonable pharmacological background, a new nutraceutical combination should be tested in clinical trials.

MATERIAL AND METHODS

This double-blind, placebo-controlled randomized clinical trial aims to evaluate the modulating effect, in a setting of controlled nutritional habits, of a combined food supplement with DIF1STAT (based on red yeast rice with a very low content of monacolins, linear aliphatic alcohols and niacin) and Olea europaea on plasma lipids and endothelial function, in a group of 40 healthy, moderately hypercholesterolemic patients in primary cardiovascular prevention.

RESULTS

After 8 weeks of treatment, when compared to the placebo group, the active treated patients experienced significant improvements of different metabolic parameters and endothelial reactivity compared to placebo. The treated patients showed a statistically significant percentage change in total cholesterol (-12.25 delta% vs. -1.8%, p < 0.01), low-density lipoprotein (LDL) cholesterol (-28.7 delta% vs. -1.1%, p < 0.01), high-density lipoprotein (HDL) cholesterol (+4.99% vs. +0.9%, p < 0.05), non-HDL cholesterol (-16.02 delta% vs. -1.5%, p < 0.01), SUA (-12.96 delta%, p < 0.05) and endothelial reactivity (+6.73% vs. -1.4%, p < 0.01). In both groups, there was no case of intolerance and the safety parameters were unchanged.

CONCLUSIONS

The tested nutraceutical association is able to significantly improve different lipid parameters compared to placebo, and endothelial reactivity compared to baseline. Even if the study power appears to be adequate for the primary endpoints, the effect on endothelial function needs confirmation in a longer clinical trial.

Tropical Oil Consumption and Cardiovascular Disease: An Umbrella Review of Systematic Reviews and Meta Analyses

The health effects of saturated fat, particularly tropical oil, on cardiovascular disease are unclear. We investigated the effect of tropical oil (palm and coconut oils), lard, and other common vegetable oils (soybean and rice bran oils) that are widely used in tropical and Asian countries on lipid profiles. We performed an umbrella review of meta-analyses and systematic reviews. Electronic databases (Medline, Scopus, Embase, and Cochrane) were searched up to December 2018 without language restriction. We identified nine meta-analyses that investigated the effect of dietary oils on lipid levels. Replacement of polyunsaturated fatty-acid-rich oils (PUFAs) and monounsaturated FA-rich oils (MUFAs) with palm oil significantly increased low-density lipoprotein cholesterol (LDL-c), by 3.43 (0.44-6.41) mg/dL and 9.18 (6.90-11.45) mg/dL, respectively, and high-density lipoprotein cholesterol (HDL-c), by 1.89 (1.23-2.55) mg/dL and 0.94 (-0.07-1.97) mg/dL, respectively. Replacement of PUFAs with coconut oil significantly increased HDL-c and total cholesterol -by 2.27 (0.93-3.6) mg/dL and 5.88 (0.21-11.55) mg/dL, respectively-but not LDL-c. Substituting lard for MUFAs and PUFAs increased LDL-c-by 8.39 (2.83-13.95) mg/dL and 9.85 (6.06-13.65) mg/dL, respectively-but not HDL-c. Soybean oil substituted for other PUFAs had no effect on lipid levels, while rice bran oil substitution decreased LDL-c. Our findings show the deleterious effect of saturated fats from animal sources on lipid profiles. Replacement of unsaturated plant-derived fats with plant-derived saturated fats slightly increases LDL-c but also increases HDL-c, which in turn may exert a neutral effect on cardiovascular health.

Impact of the Level of Adherence to Mediterranean Diet on the Parameters of Metabolic Syndrome: A Systematic Review and Meta-Analysis of Observational Studies

High adherence to the Mediterranean diet (MD) has been associated with a lower prevalence of Metabolic Syndrome (MetS). The present study aimed to investigate the impact of MD adherence on parameters of MetS. A systematic literature search was performed in PubMed, Cochrane Central Registry of Clinical Trials (CENTRAL), Scopus, EMBASE, Web of Science and Google Scholar databases. Observational studies that recorded adherence to MD and components/measures of the MetS, such as waist circumference (WC), blood pressure (BP), fasting blood glucose (FBG), high-density lipoprotein (HDL) cholesterol and triglycerides (TG), were included in this study. A total of 58 studies were included in our study. WC and TG were significantly lower in the high adherence MD group (SMD: -0.20, (95%CI: -0.40, -0.01), SMD: -0.27 (95%CI: -0.27, -0.11), respectively), while HDL cholesterol was significantly higher in the same group (SMD: -0.28 (95%CI: 0.07, 0.50). There was no difference in FBG and SBP among the two groups (SMD: -0.21 (95%CI: -0.54, 0.12) & SMD: -0.15 (95%CI: -0.38, 0.07), respectively). MD may have a positive impact on all parameters of MetS. However, further research is needed in this field.

The impact of rice bran oil consumption on the serum lipid profile in adults: a systematic review and meta-analysis of randomized controlled trials

Dyslipidemia/hyperlipidemia is recognized among the risk factors for lifestyle related diseases. A healthy diet, rich in vegetable oils such as rice bran oil (RBO), may aid to improve serum lipid levels. Thus, the aim of this study was to assess the effects of rice bran oil (RBO) consumption on serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c) and triglyceride (TG) levels in adults. The following online databases were searched for manuscripts published until October 7^th 2020: PubMed/Medline, Scopus, Clarivate Analytics' Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar. The effect sizes were expressed as weighted mean difference (WMD) with 95% confidence intervals (CI). A total of 8 eligible trials with 14 effect sizes were included in this meta-analysis. Our analysis revealed that the consumption of RBO significantly decreased serum TC (WMD: -7.29 mg/dL, 95% CI: -11.32, -3.25, P = 0.000), LDL-c (WMD: -7.62 mg/dL, 95% CI: -11.10, -4.14, P = 0.000) and TG (WMD: -9.19 mg/dL, 95% CI: -17.99, -0.38, P = 0.041) levels. So, available evidence suggests that RBO consumption can significantly decrease serum TC, LDL-c and TG levels. Hence, it may play a role in reducing dyslipidemia/hyperlipidemia risk.

The effects of canola and olive oils consumption compared to sunflower oil, on lipid profile and hepatic steatosis in women with polycystic ovarian syndrome: a randomized controlled trial

BACKGROUND

Polycystic Ovarian Syndrome (PCOS) is one of the most common endocrinopathies and metabolic disorders in women during their reproductive years. It is often associated with dyslipidemia and other risk factors of cardiovascular diseases (CVD). This study was aimed to evaluate dietary intervention effects with canola and olive oils compared to sunflower oil on lipid profile and fatty liver severity among women with PCOS.

METHOD

This study was a 10-week intervention including 72 women with PCOS. Patients were randomly assigned to three groups for receiving 25 g/day canola, olive, or sunflower oils for 10 weeks. The primary and secondary outcomes were to assess changes in lipid profile and in fatty liver severity, respectively.

RESULT

At the end of the study, 72 patients with a mean age of 29.31 were analysed. Canola oil consumption resulted in a significant reduction in serum levels of TG (P = 0.002) and TC/HDL (P = 0.021), LDL/HDL (P = 0.047), and TG/HDL (P = 0.001) ratios, however, there was no significant reduction in lipid profile following olive oil consumption. Canola (P < 0.001) and olive oils (P = 0.005) could significantly reduce the fatty liver grade. Moreover, HOMA-IR in both canola (P < 0.001) and olive (P = 0.004) groups was significantly decreased.

CONCLUSION

In total, compared to olive and sunflower oils, significant improvements in lipid profile, liver function, and HOMA-IR were observed following canola oil consumption in women with PCOS.

TRIAL REGISTRATION

IR.MUI.

RESEARCH

REC.1397.315. Registered 30 JUNE 2019 - Retrospectively registered, https://www.irct.ir/trial/38684.

Dietary oleic acid supplementation and blood inflammatory markers: a systematic review and meta-analysis of randomized controlled trials

The aim of this systematic review and meta-analysis was to analyze data from randomized controlled trials (RCTs) assessing the effects of oleic acid (OA) supplementation on blood inflammatory markers in adults. PubMed, EMBASE and Cochrane Library databases were systematically searched from 1950 to 2019, with adults and a minimum intervention duration of 4 weeks. The effect size was estimated, adopting standardized mean difference (SMD) and 95% confidence interval (CI). Of the 719 identified studies, thirty-one RCTs involving 1634 subjects were eligible. The results of this study revealed that increasing OA supplementation significantly reduced C-reactive protein (CRP) (SMD: -0.11, 95% CI: -0.21, -0.01, P = 0.038). However, dietary OA consumption did not significantly affect tumor necrosis factor (TNF) (SMD: -0.05, 95% CI: -0.19, 0.10, P = 0.534), interleukin 6 (IL-6) (SMD: 0.01, 95% CI: -0.10, 0.13, P = 0.849), fibrinogen (SMD: 0.08, 95% CI: -0.16, 0.31, P = 0.520), plasminogen activator inhibitor type 1 (PAI-1) activity (SMD: -0.11, 95% CI: -0.34, 0.12, P = 0.355), soluble intercellular adhesion molecule-1 (sICAM-1) (SMD: -0.06, 95% CI: -0.26, 0.13, P = 0.595) or soluble vascular cell adhesion molecule-1 (sVCAM-1) (SMD: -0.04, 95% CI: -0.27, 0.18, P = 0.701). Overall, the meta-analysis demonstrated that dietary OA supplementation significantly reduced CRP, yet did not affect other inflammatory markers including TNF, IL-6, fibrinogen, PAI-1 activity, sICAM-1or sVCAM-1.

Two Blends of Refined Rice Bran, Flaxseed, and Sesame Seed Oils Affect the Blood Lipid Profile of Chinese Adults with Borderline Hypercholesterolemia to a Similar Extent as Refined Olive Oil

BACKGROUND

Individual vegetable oils have a characteristic fatty acids (FA) composition and unique phytonutrient profiles, enabling formulation of oil blends that may have health-promoting effects.

OBJECTIVE

The primary objective of this study was to investigate effects of 2 oil blends made with refined rice bran, flaxseed, and sesame oils, with distinct monounsaturated to saturated FA, polyunsaturated to saturated FA, and omega-3 (n-3) to omega-6 FA ratios and different phytonutrient concentrations on blood lipid profile, compared with refined olive oil as a control. The secondary outcomes were other markers of cardiometabolic health.

METHODS

A parallel-design, randomized controlled trial compared consumption of 30 g of allocated intervention oil per day for a period of 8 wk. The study recruited 143 borderline hypercholesterolemic (LDL cholesterol: 3.06-4.51 mmol/L) Chinese volunteers between 50 and 70 y old and with a BMI (kg/m2) ≤27.5. All outcomes were measured every 2 wk, and the time × treatment interactions and the main effects of treatment and time were analyzed using an intention-to-treat approach.

RESULTS

Compared with baseline (week 0), there were significant reductions during the post-intervention time points in serum total cholesterol (-3.47%; P < 0.0001), LDL cholesterol (-4.16%; P < 0.0001), triglycerides (-10.3%; P < 0.0001), apoB (-3.93%; P < 0.0001), total to HDL-cholesterol (-3.44%; P < 0.0001) and apoB to apoA1 (-3.99%; P < 0.0001) ratios, systolic and diastolic blood pressures (-3.32% and -3.16%, respectively; both P < 0.0001), and serum glucose (-1.51%; P < 0.05) and a small but significant increase in body weight (+0.7%; P < 0.001) for all 3 intervention oils but no effects of intervention on HDL-cholesterol or apoA1 concentration. No significant effects of treatment or time × treatment interactions were found.

CONCLUSIONS

Using blended vegetable oils that are extensively consumed in Asia, this study found that specific oil blends can improve blood lipid profile and other cardiometabolic parameters, to a similar extent as refined olive oil, in Chinese adults with borderline hypercholesterolemia. This trial is registered at www.clinicaltrials.gov as NCT03964857.

Prevalent Seasoning and Cooking Fats, Arterial Stiffness and Blood Lipid Pattern in a Rural Population Sample: Data from the Brisighella Heart Study

Background: Dietary fats have been variably associated with the risk of cardiovascular disease. The aim of our study was to evaluate the association between everyday mainly used dietary fats in cooking and as seasoning and hemodynamic and lipid parameters. Methods: For this study, we selected from the Brisighella Heart Study cohort subjects who were not treated with antihypertensive drugs and report with certainty their daily mean intake of dietary fats in cooking and as seasoning. Depending on the main source of dietary fat, the involved subjects were classified as prevalent extra-virgin olive oil (EVO) users, prevalent corn oil users, prevalent users of different vegetable oils and prevalent animal fat users, and we compared their characteristics. Results: Everyday consumption of EVO as a main seasoning and cooking fat source was significantly associated to lower body mass index, visceral adiposity index, blood pressure, arterial stiffness, and cholesterolemia, when compared with predominantly animal fat users. Corn oil users also had lower blood pressure, arterial stiffness, and cholesterolemia, when compared with predominantly animal fat users, as well. In particular, in an age and systolic blood pressure adjusted model, the predictors of carotid-femoral pulse wave velocity were the prevalent use of EVO (RR = 0.84, 95% CI 0.67–0.94 vs. other prevalent fat sources), LDL-Cholesterol (RR = 1.12, 95% CI 1.02–1.42), serum uric acid (RR = 1.21, 95% CI 1.09–1.54) and estimated GFR (RR = 0.77, 95% CI 0.59–0.99). Conclusions: According to our findings, the choice of everyday seasoning and cooking fat is associated with a different metabolic and haemodynamic pattern.

Supplementation Effect of a Combination of Olive (Olea europea L.) Leaf and Fruit Extracts in the Clinical Management of Hypertension and Metabolic Syndrome

BACKGROUND

The role of herbal products in the prevention of cardiovascular disease requires supporting evidence. This open pilot study assessed the effect of 2-month supplementation of a combination of olive leaf and fruit extracts (Tensiofytol^®, Tilman SA, Baillonville, Belgium) in the clinical management of hypertension and metabolic syndrome (MetS).

METHODS

A total of 663 (pre)-hypertensive patients were enrolled by general practitioners and supplemented for two months with Tensiofytol^®, two capsules per day (100 mg/d of oleuropein and 20 mg/d of hydroxytyrosol). Systolic and diastolic blood pressures (SBP/DBP) were measured before and after treatment. Markers of MetS, high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), fasting blood glucose (FG) and waist circumference (WC), were also examined.

RESULTS

Significant reductions (p < 0.0001) in SBP/DBP (13 ± 10/7.1 ± 6.6 mmHg) were observed and similarly in pre-diabetic and diabetic patients. Improvements in SBP/DPB were independent of age and gender but greater for elevated baseline SBP/DBP. Tensiofytol^® supplementation also significantly improved markers of MetS, with a decrease of TG (11%), WC (1.4%) and FG (4.8%) and an increase of HDL-C (5.3%). Minor side effects were reported in 3.2% patients.

CONCLUSIONS

This real-life, observational, non-controlled, non-randomized pilot study shows that supplementation of a combination of olive leaf and fruit extracts may be used efficiently and safely in reducing hypertension and MetS markers.

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.

Relation of Fruits and Vegetables with Major Cardiometabolic Risk Factors, Markers of Oxidation, and Inflammation

Noncommunicable diseases (NCDs) are considered to be the leading cause of death worldwide. Inadequate fruit and vegetable intake have been recognized as a risk factor for almost all NCDs (type 2 diabetes mellitus, cancer, and cardiovascular and neurodegenerative diseases). The main aim of this review is to examine the possible protective effect that fruit and vegetable consumption or their bioactive compounds may have on the development of NCDs such as atherosclerosis. The accumulated evidence on the protective effects of adequate consumption of fruits and vegetables in some cases, or the lack of evidence in others, are summarized in the present review. The main conclusion of this review is that well-designed, large-scale, long-term studies are needed to truly understand the role fruit and vegetable consumption or their bioactive compounds have in atherosclerosis.

Perspective: Network Meta-analysis Reaches Nutrition Research: Current Status, Scientific Concepts, and Future Directions

Traditional pairwise meta-analysis (PMA) is a very useful method that pools evidence from one study design type if appropriate; its widespread use in nutrition research is an important phenomenon. Recently, a promising method for more advanced evidence-synthesis, called network meta-analysis (NMA), was introduced. NMA is an extension of PMA that enables simultaneous comparison of multiple interventions. NMA combines direct evidence (i.e., trials comparing 2 interventions directly) and indirect evidence (i.e., from a connected route via ≥1 comparators, e.g. placebo) in a network of studies. NMAs have the potential to advance knowledge in the field of nutrition as they provide insights that cannot be obtained by individual 2-arm randomized controlled trials or PMA. Thus, in this perspective paper, we aim to summarize the current (methodologic) status of published NMAs in nutrition research and emphasize advances and strengths in comparison with traditional PMA through specific examples, and highlight potential pitfalls and limitations. NMA is an emerging methodology in the field of nutrition research. A PubMed search identified only 23 nutrition research-related NMAs published since the inception of journals up to January 8, 2019 (61% of them published since 2017), compared with >5000 published PMAs. Moreover, we aim to highlight the scientific concepts and standards through the use of the following NMA example: "Which type of oils/solid fats offers the greatest impact on blood lipids?" In this regard, we discuss intervention definitions, transitivity/similarity, statistical methods, description and visualization of results, inconsistency, ranking, dissemination bias, assessing the certainty of evidence by Grading of Recommendations Assessment, Development and Evaluation, and reporting guidelines. We expect that rigorously conducted NMAs based on high-quality systematic reviews will become the new evidence synthesis benchmark in nutrition research. However, caution is warranted because abuse and misinterpretations of PMA and NMA findings could hamper the scientific field and possibly decision-making regarding public policy.

Network Meta-Analysis of Metabolic Effects of Olive-Oil in Humans Shows the Importance of Olive Oil Consumption With Moderate Polyphenol Levels as Part of the Mediterranean Diet

The beneficial role of olive oil consumption is nowadays widely recognized. However, it is not clear whether its health effects are due to the presence of monounsaturated lipids and/or to the antioxidant fraction of microconstituents present in olive oil. The aim of the present study was to analyze the exact role of olive oil in the modification of metabolic factors (glucose and circulating lipids) and explore the role of its antioxidant polyphenols. In the present work, we have performed a network meta-analysis of 30 human intervention studies, considering direct and indirect interactions and impact of each constituent. Interestingly, we show that the impact of olive oil on glucose, triglycerides, and LDL-cholesterol is mediated through an adherence to the Mediterranean diet, with the only notable effect of olive oil polyphenols being the increase of HDL-cholesterol, and the amelioration of the antioxidant and inflammatory status of the subjects. Additionally, we report for the first time that lower antioxidant polyphenol levels may be sufficient for the beneficial effects of olive oil, while we show that the lipid fraction of olive oil may be responsible for some of its beneficial actions. In all parameters examined the beneficial effect of olive oil was more pronounced in subjects with an established metabolic syndrome or other chronic conditions/diseases. In conclusion, all these findings provide new knowledge that could lead to re-establishment of the role of olive oil in human nutrition.

Olive oil consumption and human health: A narrative review

The potential health benefits of olive oil consumption, particularly within the context of the Mediterranean diet, have been extensively investigated. However, its specific health benefits remain to be confirmed. The aim of the present work is to review the scientific evidence regarding the specific impact of olive oil consumption on human health, including the prevention of cardiovascular disease, cancers, and diabetes mellitus. Ten related meta-analyses were reviewed to this effect. Olive oil consumption was found to be beneficial for several chronic non-communicable diseases (e.g. including cardiovascular disease, breast cancer and type 2 diabetes), whereas there were contradictory findings regarding its impact on several biomarkers. In conclusion, the aggregated evidence supports the assertion that olive oil consumption is beneficial for human health, and particularly for the prevention of cardiovascular diseases, breast cancer, and type 2 diabetes mellitus.

Effects of oils and solid fats on blood lipids: a systematic review and network meta-analysis

The aim of this network meta-analysis (NMA) is to compare the effects of different oils/solid fats on blood lipids. Literature searches were performed until March 2018. Inclusion criteria were as follows: i) randomized trial (≥3 weeks study length) comparing at least two of the following oils/solid fats: safflower, sunflower, rapeseed, hempseed, flaxseed, corn, olive, soybean, palm, and coconut oil, and lard, beef-fat, and butter; ii) outcomes LDL-cholesterol (LDL-C), total cholesterol (TC), HDL-cholesterol (HDL-C), and triacylglycerols (TGs). A random dose-response (per 10% isocaloric exchange) NMA was performed and surface under the cumulative ranking curve (SUCRA) was estimated. Fifty-four trials were included in the NMA. Safflower oil had the highest SUCRA value for LDL-C (82%) and TC (90%), followed by rapeseed oil (76% for LDL-C, 85% for TC); whereas, palm oil (74%) had the highest SUCRA value for TG, and coconut oil (88%) for HDL-C. Safflower, sunflower, rapeseed, flaxseed, corn, olive, soybean, palm, and coconut oil as well beef fat were more effective in reducing LDL-C (−0.42 to −0.23 mmol/l) as compared with butter. Despite limitations in these data, our NMA findings are in line with existing evidence on the metabolic effects of fat and support current recommendations to replace high saturated-fat food with unsaturated oils.

The relationship between lipid phytochemicals, obesity and its related chronic diseases

This review focuses on phytochemicals in oils, and summarizes the mechanisms of the anti-obesity effects of these compounds in in vitro studies, animal models, and human trials.