Olive Leaf
CLINICAL STUDIES ON THE FOLLOWING INGREDIENTS:
Impact of a Proprietary Standardized Olive Fruit Extract (SOFE) on Cardio-Ankle Vascular Index, Visual Analog Scale and C-Reactive Protein Assessments in Subjects with Arterial Stiffness Risk
Introduction: The chemical components of olive fruit provide a wide range of cardiovascular benefits. Arterial stiffness is an important cardiovascular risk factor and can be assessed using the Cardio-Ankle Vascular Index (CAVI).
Objective: The objective of this study was to assess the impact of a proprietary standardized olive fruit extract (SOFE) in subjects at risk for arterial stiffness.
Methods: Twelve of 36 subjects were assigned to each of the following groups for this 11-day, double-blind, placebo-controlled study: Group 1: 250 mg SOFE—50 mg active ingredient, hydroxytyrosol (dosage achieved with two capsules per day); Group 2: 500 mg SOFE—100 mg active ingredient, hydroxytyrosol (dosage achieved with two capsules per day); and Group 3: placebo.
Results: All three groups showed a decrease in CAVI scores, although no significant between-group differences were observed. Group 2 had the largest reduction, with mean CAVI scores decreasing from 11.02 to 8.91. Group 2 showed the strongest response in visual analog scale (VAS) energy intensity (11.71% increase). Results for C-reactive protein (CRP) blood levels showed no changes of statistical significance between groups. Mean triglyceride levels from Group 2 decreased by 21.64%, the most significant change among all three groups.
Conclusions: SOFE, an olive fruit extract containing many of the phytochemicals shown to provide cardiovascular benefits, was safe and well-tolerated. SOFE 500 mg had a greater effect on CAVI scores, suggesting improved arterial elasticity, and a clear reduction in triglycerides compared with placebo and SOFE 250 mg. The decreased CAVI scores suggest that increasing high-density lipoprotein cholesterol and lowering triglycerides with SOFE could potentially reduce patients’ risk of developing atherosclerosis. Although more studies are needed, positive cardiovascular health trends, including improved vessel elasticity and positive triglyceride effects, were evident with SOFE.
Source: Pais P, Villar A, Rull S. Impact of a Proprietary Standardized Olive Fruit Extract (SOFE) on Cardio-Ankle Vascular Index, Visual Analog Scale and C-Reactive Protein Assessments in Subjects with Arterial Stiffness Risk. Drugs R D. 2016 Dec;16(4):355–368. doi: 10.1007/s40268-016-0147-7.
Secoiridoids Delivered as Olive Leaf Extract Induce Acute Improvements in Human Vascular Function and Reduction of an Inflammatory Cytokine: A Randomised, Double-Blind, Placebo-Controlled, Cross-Over Trial
Abstract
The leaves of the olive plant (Olea europaea) are rich in polyphenols, of which oleuropein and hydroxytyrosol (HT) are most characteristic. Such polyphenols have been demonstrated to favourably modify a variety of cardiovascular risk factors. The aim of the present intervention was to investigate the influence of olive leaf extract (OLE) on vascular function and inflammation in a postprandial setting and to link physiological outcomes with absorbed phenolics. A randomised, double-blind, placebo-controlled, cross-over, acute intervention trial was conducted with eighteen healthy volunteers (nine male, nine female), who consumed either OLE (51 mg oleuropein; 10 mg HT), or a matched control (separated by a 4-week wash out) on a single occasion. Vascular function was measured by digital volume pulse (DVP), while blood collected at baseline, 1, 3 and 6 h was cultured for 24 h in the presence of lipopolysaccharide in order to investigate effects on cytokine production. Urine was analysed for phenolic metabolites by HPLC. DVP-stiffness index and ex vivo IL-8 production were significantly reduced (P< 0·05) after consumption of OLE compared to the control. These effects were accompanied by the excretion of several phenolic metabolites, namely HT and oleuropein derivatives, which peaked in urine after 8–24 h. The present study provides the first evidence that OLE positively modulates vascular function and IL-8 production in vivo, adding to growing evidence that olive phenolics could be beneficial for health.
Source: Lockyer S, Corona G, Yaqoob P, Spencer J. P. E., Rowland I. Secoiridoids delivered as olive leaf extract induce acute improvements in human vascular function and reduction of an inflammatory cytokine: a randomised, double-blind, placebo-controlled, cross-over trial. British Journal of Nutrition , Volume 114 , Issue 1 , 14 July 2015 , pp. 75 - 83. doi: 10.1017/S0007114515001269
Potential Health Benefits of Olive Oil and Plant Polyphenols
Abstract
Beneficial effects of natural plant polyphenols on the human body have been evaluated in a number of scientific research projects. Bioactive polyphenols are natural compounds of various chemical structures. Their sources are mostly fruits, vegetables, nuts and seeds, roots, bark, leaves of different plants, herbs, whole grain products, processed foods (dark chocolate), as well as tea, coffee, and red wine. Polyphenols are believed to reduce morbidity and/or slow down the development of cardiovascular and neurodegenerative diseases as well as cancer. Biological activity of polyphenols is strongly related to their antioxidant properties. They tend to reduce the pool of reactive oxygen species as well as to neutralize potentially carcinogenic metabolites. A broad spectrum of health-promoting properties of plant polyphenols comprises antioxidant, anti-inflammatory, anti-allergic, anti-atherogenic, anti-thrombotic, and anti-mutagenic effects. Scientific studies present the ability of polyphenols to modulate the human immune system by affecting the proliferation of white blood cells, and also the production of cytokines or other factors that participate in the immunological defense. The aim of the review is to focus on polyphenols of olive oil in context of their biological activities.
Source: Gorzynik-Debicka M, Przychodzen P, Cappello F, Kuban-Jankowska A, Marino Gammazza A, Knap N, Wozniak M, Gorska-Ponikowska M. Potential Health Benefits of Olive Oil and Plant Polyphenols. Int J Mol Sci. 2018 Feb 28;19(3):686. doi: 10.3390/ijms19030686. PMID: 29495598; PMCID: PMC5877547.
Olive Leaf Extracts Act as Modulators of the Human Immune Response
Background: Olive tree leaves have been used in the Mediterranean area as traditional medicine in virtue of their healthy effects. Olive leaf extracts (OLEs) contain higher amounts of polyphenols than those detected in the extra virgin olive oil and fruit. Several lines of evidence support the cardioprotective, anti-oxidant and anti-inflammatory activities exerted by OLEs.
Methods: Peripheral blood mononuclear cells from twenty-five healthy donors were cultured in the presence of 3 µg of two OLE extracts, extract A (resuspended in water) and extract B (resuspended in 70% ethanol). After harvesting, cell pellets were used for cytofluorimetric phenotyping, while supernatants were assayed for cytokine release by means of ELISA. Furthermore, in the same supernatants nitric oxide (NO) content was determined.
Results: Both extracts, but especially extract A, increased absolute numbers of CD8+ and natural killer (NK) cells. In addition, an increased production of interferon (IFN)-γ by both extracts as an expression of T helper (h)1 activation was observed. Finally, both extracts enhanced NO release.
Conclusion: OLEs, and mostly extract A, are able to in vitro modify healthy human immune response by increasing IFN-γ production which seems to be associated to the higher absolute numbers of CD8+ and NK cells and this may suggest a reinforcement of the anti-tumor activity. Furthermore, increased levels of NO may indicate the potential cardioprotective effects exerted by OLEs in virtue of their vasodilation dependent activity. Finally, OLEs are able to maintain the equilibrium between T regulatory cells and Th17 cells as evidenced by unmodified levels of interleukin (IL)-IL-10 and IL-17, respectively. In the light of these results, OLEs are potential therapeutic compounds for the treatment of chronic inflammatory disease, also preventing cardiovascular event outcome.
Source: Magrone T, Spagnoletta A, Salvatore R, Magrone M, Dentamaro F, Russo MA, Difonzo G, Summo C, Caponio F, Jirillo E. Olive Leaf Extracts Act as Modulators of the Human Immune Response. Endocr Metab Immune Disord Drug Targets. 2018;18(1):85-93. doi: 10.2174/1871530317666171116110537. PMID: 29149822.
Olive Leaf Extract Supplementation Combined with Calorie-Restricted Diet on Reducing Body Weight and Fat Mass in Obese Women: Result of a Randomized Control Trial
Abstract
The present trial aims to evaluate a supplementation of the olive leaf extract (OLE) in adjunct with a weight loss diet on anthropometric indices, glycemic indices, lipid profile, as well as the level of adipokines, and free fatty acid in obese women. We carried out an 8-week randomized, placebo-controlled, double-blind, parallel-group, clinical trial. The participants were randomly stratified according to age and they were assigned to one of the two study groups: Standard weight loss diet (estimated daily energy requirements minus 500 kcal) + OLE supplementation (n = 35) in intervention group or Standard weight loss diet (estimated daily energy requirements minus 500 kcal) + placebo (n = 35) in placebo group. The study groups were homogeneous regarding the baseline age, height, weight, body mass index (BMI), waist circumferences, married status, and physical activity levels (p > 0.05). The results of analysis of covariance presented significant decreases in BMI, fat mass, and body weight in the OLE group compared to those in the placebo group (p < 0.05). At the end of the study, the serum levels of fasting blood sugar, insulin, low-density lipoprotein cholesterol, total cholesterol, leptin, fatty free acid, and homeostasis model assessment-insulin resistance significantly decreased, and serum levels of high-density lipoprotein cholesterol and adiponectin elevated in the intervention group (p < 0.05). Based on results it seems that the addition of OLE to a hypocaloric diet for 8-week compared with a hypocaloric diet alone may be more effective in modifying obesity and metabolic risk factors.
Source: Haidari F, Shayesteh F, Mohammad-Shahi M, Jalali M-T, Ahmadi-Angali K. Olive Leaf Extract Supplementation Combined with Calorie-Restricted Diet on Reducing Body Weight and Fat Mass in Obese Women: Result of a Randomized Control Trial. Clin Nutr Res. 2021 Oct 31;10(4):314-329. doi: 10.7762/cnr.2021.10.4.314. PMID: 34796136; PMCID: PMC8575641.
Olive (Olea Europaea L.) Leaf Polyphenols Improve Insulin Sensitivity in Middle-Aged Overweight Men: A Randomized, Placebo-Controlled, Crossover Trial
Background: Olive plant leaves (Olea europaea L.) have been used for centuries in folk medicine to treat diabetes, but there are very limited data examining the effects of olive polyphenols on glucose homeostasis in humans.
Objective: To assess the effects of supplementation with olive leaf polyphenols (51.1 mg oleuropein, 9.7 mg hydroxytyrosol per day) on insulin action and cardiovascular risk factors in middle-aged overweight men.
Design: Randomized, double-blinded, placebo-controlled, crossover trial in New Zealand. 46 participants (aged 46.4 ± 5.5 years and BMI 28.0 ± 2.0 kg/m(2)) were randomized to receive capsules with olive leaf extract (OLE) or placebo for 12 weeks, crossing over to other treatment after a 6-week washout. Primary outcome was insulin sensitivity (Matsuda method). Secondary outcomes included glucose and insulin profiles, cytokines, lipid profile, body composition, 24-hour ambulatory blood pressure, and carotid intima-media thickness.
Results: Treatment evaluations were based on the intention-to-treat principle. All participants took >96% of prescribed capsules. OLE supplementation was associated with a 15% improvement in insulin sensitivity (p = 0.024) compared to placebo. There was also a 28% improvement in pancreatic β-cell responsiveness (p = 0.013). OLE supplementation also led to increased fasting interleukin-6 (p = 0.014), IGFBP-1 (p = 0.024), and IGFBP-2 (p = 0.015) concentrations. There were however, no effects on interleukin-8, TNF-α, ultra-sensitive CRP, lipid profile, ambulatory blood pressure, body composition, carotid intima-media thickness, or liver function.
Conclusions: Supplementation with olive leaf polyphenols for 12 weeks significantly improved insulin sensitivity and pancreatic β-cell secretory capacity in overweight middle-aged men at risk of developing the metabolic syndrome.
Source: de Bock M, Derraik JGB, Brennan CM, Biggs JB, Morgan PE, Hodgkinson SC, Hofman PL, Cutfield WS. Olive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trial. PLoS One. 2013;8(3):e57622. doi: 10.1371/journal.pone.0057622. Epub 2013 Mar 13. PMID: 23516412; PMCID: PMC3596374.
The Effect of Olive Leaf Extract on Upper Respiratory Illness in High School Athletes: A Randomised Control Trial
Abstract
Upper respiratory illness (URI) has a major impact on both training and competition in an athletic setting. High school athletes are a sub-category who have reported higher illness rates than professional and sub-elite high school athletes of the same sport. Olive leaf extract (OLE) is an over-the-counter supplement that contains polyphenols, notably oleuropein and hydroxytyrosol, that have antiviral, antibacterial, anti-inflammatory and antioxidant properties that may reduce URI rates. Thirty-two high school students who play sport for the elite team at their school were recruited to a randomised controlled trial and allocated to a daily placebo or OLE (extent equivalent to 20 g of olive leaf, containing 100 mg oleuropein) supplementation for nine weeks during their competitive season. Twice weekly measures of wellbeing, training load and respiratory illness (sporting upper respiratory illness (SUPPRESS) questionnaire) were recorded at trainings, meetings or games. There was no significant difference in illness incidence (odds ratio (OR): 1.02 (95% confidence interval (CI) 0.21–4.44)), but there was a significant 28% reduction in sick days (OR: 0.72 (95% CI 0.56–0.93) p-value = 0.02) when supplemented with OLE. The dietary intakes of the athletes were sub-optimal with regard to immune support. OLE supplementation over a season did not significantly reduce URI incidence, but did decrease duration in high school athletes, potentially aiding return to play.
Source: Somerville V, Moore R, Braakhuis A. The Effect of Olive Leaf Extract on Upper Respiratory Illness in High School Athletes: A Randomised Control Trial. Nutrients. 2019 Feb 9;11(2):358. doi: 10.3390/nu11020358. PMID: 30744120; PMCID: PMC6412228.
The Effects of Olive Leaf Extract on Cardiovascular Risk Factors in the General Adult Population: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Background: The aim of this systematic review and meta-analysis was to determine the effect of olive leaf extract (OLE) supplementation on cardiovascular-related variables, including lipid, glycemic, inflammatory, liver and renal-related factors, as well as blood pressure.
Methods: PubMed, ISI Web of Science, Scopus, and Cochrane library were searched, up to October 2021, for relevant controlled trials. Mean differences and standard deviations were pooled for all outcomes, using a random-effects model. The methodological quality, as well as quality of evidence were assessed using standard tools.
Results: Twelve studies (n = 819 participants) were included in our analyses. Overall analyses showed that OLE supplementation significantly decreased triglyceride (TG) levels (WMD = − 9.51 mg/dl, 95% CI − 17.83, − 1.18; P = 0.025; I2 = 68.7%; P-heterogeneity = 0.004), and systolic blood pressure (SBP) (WMD = − 3.86 mmHg, 95% CI − 6.44, − 1.28 mmHg; P = 0.003; I2 = 19.9%; P-heterogeneity = 0.28). Subgroup analyses also revealed a significant improvement in SBP (− 4.81 mmHg) and diastolic blood pressure (− 2.45 mmHg), TG (− 14.42 mg/dl), total cholesterol (TC) (− 9.14 mg/dl), and low-density lipoprotein-C (LDL-C) (− 4.6 mg/dl) measurements, in patients with hypertension. Significant reductions were also observed in TC (− 6.69 mg/dl), TG (− 9.21 mg/dl), and SBP (− 7.05 mmHg) in normal-weight individuals. However, no meaningful changes were seen in glucose hemostasis, liver and kidney, or inflammatory markers.
Conclusion: The present study revealed that supplementation with OLE yielded beneficial effects for blood pressure and lipid profile in adults, especially in patients with hypertension. As the quality of evidence for glucose hemostasis variables, liver, kidney, and inflammatory markers, were low-to-very low, higher quality RCTs may impact the overarching results.
Source: Razmpoosh E, Abdollahi S, Mousavirad M, Clark CCT, Soltani S. The effects of olive leaf extract on cardiovascular risk factors in the general adult population: a systematic review and meta-analysis of randomized controlled trials. Diabetol Metab Syndr. 2022 Oct 21;14:151. doi: 10.1186/s13098-022-00920-y. PMID: 36271476; PMCID: PMC9585723.