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

Eur J Nutr. 2017 Jun;56(4):1421-1432. doi: 10.1007/s00394-016-1188-y. Epub 2016 Mar 7.

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.

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.

Keywords: Blood pressure; Cardiovascular disease; Oleuropein; Olive leaf; Plasma lipids; Polyphenols.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Biomarkers / blood
  • Blood Pressure / drug effects
  • Body Mass Index
  • C-Reactive Protein / metabolism
  • Cholesterol / blood*
  • Cross-Over Studies
  • Cytokines / blood
  • Double-Blind Method
  • Humans
  • Inflammation / blood
  • Iridoids / pharmacology
  • Male
  • Middle Aged
  • Olea / chemistry*
  • Plant Extracts / pharmacology*
  • Plant Leaves / chemistry*
  • Polyphenols / pharmacology*
  • Risk Factors
  • Triglycerides / blood*
  • Young Adult

Substances

  • Biomarkers
  • Cytokines
  • Iridoids
  • Plant Extracts
  • Polyphenols
  • Triglycerides
  • oleuropein
  • C-Reactive Protein
  • Cholesterol