Supplementation of Olive Oil and Flaxseed Oil on Blood Pressure and Inflammation in Healthy and At-Risk Adults: A Systematic Literature Review and Meta-Analysis

source extracted confidence: high 2026-04-09
#adult #humans #biomarkers #blood-pressure #dietary-supplements

Supplementation of Olive Oil and Flaxseed Oil on Blood Pressure and Inflammation in Healthy and At-Risk Adults: A Systematic Literature Review and Meta-Analysis

McNabb et al., 2024 | Curr Hypertens Rev | Meta Analysis

Citation

McNabb Tara B, Young Ian, ... Tou Janet C. Supplementation of Olive Oil and Flaxseed Oil on Blood Pressure and Inflammation in Healthy and At-Risk Adults: A Systematic Literature Review and Meta-Analysis. Curr Hypertens Rev. 2024;20(3):141-155. doi:10.2174/0115734021337760241104063418

Abstract

BACKGROUND: Adding olive oil (OO) and flaxseed oil (FLO) to the diet has been reported to improve endothelial function and reduce inflammation. However, the efficacy of supplementing OO and FLO on blood pressure (BP) in normo-, pre-, and hypertensive stage 1 adults is uncertain. OBJECTIVE: This study aimed to systematically review the literature on OO and FLO supplementation on BP and select inflammatory markers in healthy adults and adults at risk of hypertension. METHODS: Four databases, PubMed, CINHAL, Web of Science, and Medline (Ovid), were searched from inception until October 2023 for randomized control trials (RCTs) comparing OO and FLO supplementation in normotensive or adults at risk of hypertension. The outcomes included were systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) and at least one inflammatory marker, C-reactive protein (CRP), interleukin6 (IL6), or tumor necrosis factor alpha (TNFα). The risk of bias was assessed using version 2 of the Cochrane risk of bias tool for RCTs, publication bias visualization was performed using funnel plots, and meta-analysis was completed to generate average estimates of effects in 2024. RESULTS: Seventeen RCTs, comprising 14 studies on OO and 3 on FLO, met the inclusion criteria. Meta-analysis using a random-effects model reported no significant effect on SBP n=17 mean difference (MD) -0.48; 95% CI: -1.76, 0.80; p=0.65, I2 =0%) and DBP (n=16, MD -0.47; 95% CI: -1.33, 0.39; p=0.65, I2 =0%) or inflammatory markers, CRP (n=8, MD 0.11; 95% CI: -1.18, 0.40; p=0.98, I2 =0%), IL6 (n=3, MD -0.15; 95% CI: -0.57, 0.27; p=0.87, I2 =0%), and TNFα (n=3, MD-0.08; 95% CI: -0.12, -0.03; p=0.98, I2 =0%). CONCLUSION: Longer-duration, higher-dose, and larger-scale RCTs are needed to better understand the efficacy of OO and FLO supplementation on BP. Further insight will better inform dietary supplement use for preventing hypertension.

Key Findings

Seventeen RCTs, comprising 14 studies on OO and 3 on FLO, met the inclusion criteria. Meta-analysis using a random-effects model reported no significant effect on SBP n=17 mean difference (MD) -0.48; 95% CI: -1.76, 0.80; p=0.65, I2 =0%) and DBP (n=16, MD -0.47; 95% CI: -1.33, 0.39; p=0.65, I2 =0%) or inflammatory markers, CRP (n=8, MD 0.11; 95% CI: -1.18, 0.40; p=0.98, I2 =0%), IL6 (n=3, MD -0.15; 95% CI: -0.57, 0.27; p=0.87, I2 =0%), and TNFα (n=3, MD-0.08; 95% CI: -0.12, -0.03; p=0.98, I2 =0%)

Outcomes Measured

  • blood pressure
  • systolic blood pressure
  • diastolic blood pressure
  • C-reactive protein
  • inflammatory markers

Population

Field Value
Population healthy adults
Sample Size 17
Age Range See abstract
Condition hypertension

MeSH Terms

  • Adult
  • Humans
  • Biomarkers
  • Blood Pressure
  • Dietary Supplements
  • Hypertension
  • Inflammation
  • Inflammation Mediators
  • Linseed Oil
  • Olive Oil
  • Randomized Controlled Trials as Topic
  • Treatment Outcome

Evidence Classification

  • Level: Meta Analysis
  • Publication Types: Journal Article, Systematic Review, Meta-Analysis
  • Vertical: flaxseed

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09