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

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Lockyer, Stacey ; Rowland, Ian ; Spencer, Jeremy Paul Edward ; Yaqoob, Parveen ; Stonehouse, Welma (2016)
  • Publisher: Springer Berlin Heidelberg
  • Journal: European Journal of Nutrition, volume 56, issue 4, pages 1,421-1,432 (issn: 1436-6207, eissn: 1436-6215)
  • Related identifiers: pmc: PMC5486627, doi: 10.13039/100008354, doi: 10.1007/s00394-016-1188-y
  • Subject: Medicine (miscellaneous) | Polyphenols | Cardiovascular disease | Blood pressure | Olive leaf | Original Contribution | Oleuropein | Nutrition and Dietetics | Plasma lipids

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. Methods A 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. Results Daytime [−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. Conclusion Our data support previous research, suggesting that OLE intake engenders hypotensive and lipid-lowering effects in vivo. Electronic supplementary material The online version of this article (doi:10.1007/s00394-016-1188-y) contains supplementary material, which is available to authorized users.
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