Beneficial effects of dietary supplementation with olive oil, oleic acid, or hydroxytyrosol in metabolic syndrome: Systematic review and meta-analysis

Rosario Pastor; Cristina Bouzas; Josep A Tur

doi:10.1016/j.freeradbiomed.2021.06.017

Beneficial effects of dietary supplementation with olive oil, oleic acid, or hydroxytyrosol in metabolic syndrome: Systematic review and meta-analysis

Free Radic Biol Med. 2021 Aug 20:172:372-385. doi: 10.1016/j.freeradbiomed.2021.06.017. Epub 2021 Jun 18.

Authors

Rosario Pastor¹, Cristina Bouzas², Josep A Tur³

Affiliations

¹ Research Group on Community Nutrition and Oxidative Stress, University of the Balearic Islands-IUNICS & IDISBA, E-07122, Palma de Mallorca, Spain; Faculty of Health Sciences, Catholic University of Avila, 05005, Avila, Spain. Electronic address: rosario.pastor@ucavila.es.
² Research Group on Community Nutrition and Oxidative Stress, University of the Balearic Islands-IUNICS & IDISBA, E-07122, Palma de Mallorca, Spain; Faculty of Health Sciences, Catholic University of Avila, 05005, Avila, Spain; CIBEROBN (Physiopathology of Obesity and Nutrition), Instituto de Salud Carlos III, 28029, Madrid, Spain. Electronic address: cristina.bouzas@uib.es.
³ Research Group on Community Nutrition and Oxidative Stress, University of the Balearic Islands-IUNICS & IDISBA, E-07122, Palma de Mallorca, Spain; CIBEROBN (Physiopathology of Obesity and Nutrition), Instituto de Salud Carlos III, 28029, Madrid, Spain. Electronic address: pep.tur@uib.es.

PMID: 34153478
DOI: 10.1016/j.freeradbiomed.2021.06.017

Abstract

Background and aims: Olive oil and components might have a beneficial effect on Metabolic Syndrome (MetS). The aim of this review and meta-analysis was to assess whether those effects are related to hydroxytyrosol or oleic acid contents, or the combination of them as olive oil, and how powerful is this effect.

Methods: A systematic literature search was performed in MEDLINE via Pubmed, Web of Science (WOS) core collection, and Virtual Health Library (VHL) via LILACS and IBECS (Spain). MeSH terms used were "obesity", "body weight", "body mass index", "adipose tissue", "lipid metabolism", "LDL", "HDL", "VLDL", "insulin resistance", "glucose", "insulin", "hypertension", "arterial pressure", "olive oil", "oleic acid", and other (non-MeSH) terms: "total antioxidant capacity", "total antioxidant status", "hydroxytyrosol" (PROSPERO ID: CRD42021247614). Results of the included studies were meta-analyzed with the RevMan 5.3 program, assuming a random effects model.

Results: 76 articles (67 different trials) were identified. Hydroxytyrosol had no effect on MetS [combined standardized mean differences (SMD) = 0.01 (CI 95%: [-0.23, 0.25], I² = 83%; p = 0.920)]. Oleic acid had no significant beneficial effect on MetS [SMD = 0.03 (CI 95%: [-0.01, 0.07], I² = 0%); p = 0.150], but it improved lipid profile [SMD = 0.06 (CI 95%: [-0.00, 0.12], I² = 0%); p = 0. 050]. Olive oil had no effect on MetS [SMD = -0.01 (CI 95%: [-0.05, 0.03]), I² = 55%; p = 0.550)]. The supplementation with hydroxytyrosol, oleic acid or olive oil showed a beneficial effect on antioxidant capacity related to components of MetS [SMD = 0.31 (CI 95%: [-0.34, 0.95], I² = 81%)]; p = 0.35).

Conclusion: Most articles compared olive oil and oleic acid with other strategies specially designed for MetS management. Our findings suggest that olive oil or oleic acid consumption are as good as the other strategies to manage MetS.

Keywords: Dyslipidemia; Hydroxytyrosol; Hypertension; Insulin resistance; Metabolic syndrome; Obesity; Oleic acid; Olive oil; Systematic review; Total antioxidant capacity; Total antioxidant status; meta-Analysis.

Publication types

Meta-Analysis
Research Support, Non-U.S. Gov't
Review
Systematic Review

MeSH terms

Dietary Supplements
Humans
Metabolic Syndrome* / drug therapy
Oleic Acid*
Olive Oil
Phenylethyl Alcohol / analogs & derivatives

Substances

Olive Oil
3,4-dihydroxyphenylethanol
Oleic Acid
Phenylethyl Alcohol