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Review
. 2015 Sep 11;7(9):7651-75.
doi: 10.3390/nu7095356.

Effects of Olive Oil on Markers of Inflammation and Endothelial Function-A Systematic Review and Meta-Analysis

Lukas Schwingshackl  1   2 , Marina Christoph  3 , Georg Hoffmann  4
Affiliations
Review

Effects of Olive Oil on Markers of Inflammation and Endothelial Function-A Systematic Review and Meta-Analysis

Lukas Schwingshackl et al. Nutrients. .

Abstract

The aim of the present systematic review was to synthesize data from randomized controlled trials investigating the effects of olive oil on markers of inflammation or endothelial function. Literature search in electronic databases Cochrane Trial Register, EMBASE, and MEDLINE was performed. Thirty studies enrolling 3106 participants fulfilled the selection criteria. Pooled effects of different interventions were assessed as mean difference using a random effects model. Olive oil interventions (with daily consumption ranging approximately between 1 mg and 50 mg) resulted in a significantly more pronounced decrease in C-reactive protein (mean difference: -0.64 mg/L, (95% confidence interval (CI) -0.96 to -0.31), p < 0.0001, n = 15 trials) and interleukin-6 (mean difference: -0.29 (95% CI -0.7 to -0.02), p < 0.04, n = 7 trials) as compared to controls, respectively. Values of flow-mediated dilatation (given as absolute percentage) were significantly more increased in individuals subjected to olive oil interventions (mean difference: 0.76% (95% CI 0.27 to 1.24), p < 0.002, n = 8 trials). These results provide evidence that olive oil might exert beneficial effects on endothelial function as well as markers of inflammation and endothelial function, thus representing a key ingredient contributing to the cardiovascular-protective effects of a Mediterranean diet. However, due to the heterogeneous study designs (e.g., olive oil given as a supplement or as part of dietary pattern, variations in control diets), a conservative interpretation of the results is necessary.

Keywords: C-reactive protein; Mediterranean diet; cardiovascular disease; flow-mediated dilatation; interleukin-6.

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Figures

Figure 1
Figure 1
Flow diagram.
Figure 2
Figure 2
Risk of bias assessment tool. (A) Across trials, information is either from trials at low risk of bias (green), or from trials at unclear risk of bias (yellow), or from trials at high risk of bias (red). (B) For each study, every bias domain will be checked, the given summary represents an assessment of bias risk across studies. For each bias domain, low risk of bias means that information is from studies at low risk of bias (green), high risk of bias indicates the proportion of information from studies at high risk of bias which might be sufficient to affect the interpretation of the results (red), and unclear risk of bias refers to information from studies at low or unclear risk of bias (yellow).
Figure 2
Figure 2
Risk of bias assessment tool. (A) Across trials, information is either from trials at low risk of bias (green), or from trials at unclear risk of bias (yellow), or from trials at high risk of bias (red). (B) For each study, every bias domain will be checked, the given summary represents an assessment of bias risk across studies. For each bias domain, low risk of bias means that information is from studies at low risk of bias (green), high risk of bias indicates the proportion of information from studies at high risk of bias which might be sufficient to affect the interpretation of the results (red), and unclear risk of bias refers to information from studies at low or unclear risk of bias (yellow).
Figure 3
Figure 3
Effects of olive oil on C-reactive protein (mg/L). Forest plot showing pooled mean differences with 95% confidence intervals (CI) for 14 randomized controlled diets. For each study, the shaded square represents the point estimate of the intervention effect. The horizontal line joins the lower and upper limits of the 95% CI of these effects. The area of the shaded square reflects the relative weight of the study in the respective meta-analysis. The diamond at the bottom of the graph represents the pooled MD with the 95% CI for all study groups. MedD = Mediterranean diet.
Figure 4
Figure 4
Effects of olive oil on interleukin-6 (pg/mL). Forest plot showing pooled mean differences with 95% confidence intervals (CI) for seven randomized controlled diets. For each study, the shaded square represents the point estimate of the intervention effect. The horizontal line joins the lower and upper limits of the 95% CI of these effects. The area of the shaded square reflects the relative weight of the study in the respective meta-analysis. The diamond at the bottom of the graph represents the pooled MD with the 95% CI for all study groups. MedD = Mediterranean diet.
Figure 5
Figure 5
Effects of olive oil on flow-mediated dilatation (%, absolute percentage). Forest plot showing pooled mean differences with 95% confidence intervals (CI) for eight randomized controlled diets. For each study, the shaded square represents the point estimate of the intervention effect. The horizontal line joins the lower and upper limits of the 95% CI of these effects. The area of the shaded square reflects the relative weight of the study in the respective meta-analysis. The diamond at the bottom of the graph represents the pooled MD with the 95% CI for all study groups. Please note that the labeling of the X-axis has been switched as compared to Figure 3 and Figure 4, respectively, since for flow-mediated dilatation an increase is considered to be favorable. MedD = Mediterranean diet.
Figure 6
Figure 6
Funnel plot showing study precision against the mean differences effect estimate with 95% confidence intervals for C-reactive protein. SE = Standard error.
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References

    1. Lim S.S., Vos T., Flaxman A.D., Danaei G., Shibuya K., Adair-Rohani H., Amann M., Anderson H.R., Andrews K.G., Aryee M., et al. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: A systematic analysis for the global burden of disease study 2010. Lancet. 2012;380:2224–2260. doi: 10.1016/S0140-6736(12)61766-8. - DOI - PMC - PubMed
    1. Perez-Martinez P., Lopez-Miranda J., Blanco-Colio L., Bellido C., Jimenez Y., Moreno J.A., Delgado-Lista J., Egido J., Perez-Jimenez F. The chronic intake of a mediterranean diet enriched in virgin olive oil, decreases nuclear transcription factor κB activation in peripheral blood mononuclear cells from healthy men. Atherosclerosis. 2007;194:e141–e146. doi: 10.1016/j.atherosclerosis.2006.11.033. - DOI - PubMed
    1. Sanchez-Fidalgo S., Sanchez de Ibarguen L., Cardeno A., Alarcon de la Lastra C. Influence of extra virgin olive oil diet enriched with hydroxytyrosol in a chronic dss colitis model. Eur. J. Nutr. 2012;51:497–506. doi: 10.1007/s00394-011-0235-y. - DOI - PubMed
    1. Moreno-Luna R., Muñoz-Hernandez R., Miranda M.L., Costa A.F., Jimenez-Jimenez L., Vallejo-Vaz A.J., Muriana F.J., Villar J., Stiefel P. Olive oil polyphenols decrease blood pressure and improve endothelial function in young women with mild hypertension. Am. J. Hypertens. 2012;25:1299–1304. doi: 10.1038/ajh.2012.128. - DOI - PubMed
    1. Schwingshackl L., Hoffmann G. Monounsaturated fatty acids and risk of cardiovascular disease: Synopsis of the evidence available from systematic reviews and meta-analyses. Nutrients. 2012;4:1989–2007. doi: 10.3390/nu4121989. - DOI - PMC - PubMed

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