Impact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trial

Abstract

Purpose Dietary polyphenols have been demonstrated to favourably modify a number of cardiovascular risk markers such as blood pressure (BP), endothelial function and plasma lipids. We conducted a randomised, double-blind, controlled, crossover trial to investigate the effects of a phenolic-rich olive leaf extract (OLE) on BP and a number of associated vascular and metabolic measures. MethodsA total of 60 pre-hypertensive [systolic blood pressure (SBP): 121–140 mmHg; diastolic blood pressure (DBP): 81–90 mmHg] males [mean age 45 (±SD 12.7 years, BMI 26.7 (±3.21) kg/m2] consumed either OLE (136 mg oleuropein; 6 mg hydroxytyrosol) or a polyphenol-free control daily for 6 weeks before switching to the alternate arm after a 4-week washout.ResultsDaytime [−3.95 (±SD 11.48) mmHg, p = 0.027] and 24-h SBP [−3.33 (±SD 10.81) mmHg, p = 0.045] and daytime and 24-h DBP [−3.00 (±SD 8.54) mmHg, p = 0.025; −2.42 (±SD 7.61) mmHg, p = 0.039] were all significantly lower following OLE intake, relative to the control. Reductions in plasma total cholesterol [−0.32 (±SD 0.70) mmol/L, p = 0.002], LDL cholesterol [−0.19 (±SD 0.56) mmol/L, p = 0.017] and triglycerides [−0.18 (±SD 0.48), p = 0.008] were also induced by OLE compared to control, whilst a reduction in interleukin-8 [−0.63 (±SD 1.13) pg/ml; p = 0.026] was also detected. Other markers of inflammation, vascular function and glucose metabolism were not affected.ConclusionOur data support previous research, suggesting that OLE intake engenders hypotensive and lipid-lowering effects in vivo.Electronic supplementary materialThe online version of this article (doi:10.1007/s00394-016-1188-y) contains supplementary material, which is available to authorized users.

Human Intervention Study to Assess the Effects of Supplementation with Olive Leaf Extract on Peripheral Blood Mononuclear Cell Gene Expression

“…This corresponds to the most recent in vivo work with the same OLE supplement in humans in which reduced levels of IL-8 were observed in blood taken from participants after a six-week intervention [9]. Ex vivo work by this group has also shown that OLE is able to downregulate IL-8 [32].…”

“…Inhibiting COX -2 and thereby reducing prostaglandins could also explain improvements in Blood Pressure (BP) measured in humans after OLE consumption [9]. HT administered to rats was able to reduce thromboxane B 2 and platelet aggregation in blood [65].…”

“…The study was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12615001021561). An 8-week intervention time was based on a previous 6-week intervention study measuring changes in BP after supplementation with the same OLE product [9]. A more recent study looking at polyphenols in the diet using a parallel design also used 8 weeks to successfully detect changes in inflammation [74].…”

“…Recent research has shown improved blood pressure in hypertensive males with OLE [9] and improved insulin sensitivity in overweight males [10]. These studies have focused on specific outcomes or biomarkers such as improved insulin sensitivity or the expression of specific cytokines; however, a more comprehensive analysis of the changes in gene expression has not been undertaken.…”

Potential Health Benefits of Olive Leaf

“…Ayrıca bu çalışmada zeytin yaprağı ekstresi verilen grupta lipid profili olumlu yönde ilerlemiştir. 37 Hipertansiyonu olan gönüllü hastalar üzerinde yapılan bir çalışmada, 1600 mg oleuropein alımı-nın sistolik ve diastolik kan basıncını azalttığı aynı zamanda nitrik oksit (NO) düzeyini arttırdığı gös-terilmiştir. 38 Hipertansiyon çeşitlerinin bir ço-ğunda, artmış kan basıncı ile birlikte endotel bağımlı gevşemede bir azalma oluşmaktadır.…”