Significant metabolic improvement by a water extract of olives: animal and human evidence

Eur J Nutr. 2019 Sep;58(6):2545-2560. doi: 10.1007/s00394-018-1807-x. Epub 2018 Aug 9.


Purpose: Dyslipidemia and impaired glucose metabolism are the main health issues of growing prevalence and significant high healthcare cost, requiring novel prevention and/or therapeutic approaches. Epidemiological and animal studies revealed that olive oil is an important dietary constituent, inducing normolipidemia. However, no studies have specifically investigated the polyphenol-rich water extract of olives (OLWPE), generated during olive oil production.

Methods: In the present work, we initially examined the effect of OLPWE on animals' metabolic parameters. Rats fed with a high-fat diet were treated with three different doses of OLPWE for 4 months. Additionally, bioavailability was explored. Afterwards, OLWPE's metabolic effect was explored in humans. Healthy volunteers consumed microencapsulated OLWPE for 4 weeks, in a food matrix [one portion (30 g) of a meat product].

Results: High-fat-fed rats developed a metabolic dysfunction, with increased LDL and insulin levels and decreased HDL; this syndrome was significantly impaired when treated with OLWPE. Treated rats had increased total plasma antioxidant capacity, while several phenolic compounds were detected in their blood. These findings were also verified in humans that consumed OLWPE, daily, for 4 weeks. Interestingly, in individuals with elements of cardio-metabolic risk, OLWPE consumption resulted in reduced glucose, insulin, total cholesterol, LDL and oxLDL levels.

Conclusions: Our data clearly show that OLWPE can improve glucose and lipid profile, indicating its possible use in the design of functional food and/or therapeutic interventions.

Keywords: Glucose; Lipid; Metabolism; Olive extract; Olive oil.

MeSH terms

  • Animals
  • Antioxidants / administration & dosage
  • Antioxidants / metabolism
  • Antioxidants / pharmacology*
  • Blood Glucose
  • Cholesterol / blood
  • Diet, High-Fat / adverse effects*
  • Greece
  • Humans
  • Insulin / blood
  • Male
  • Models, Animal
  • Olea*
  • Phenols / blood
  • Plant Extracts / administration & dosage
  • Plant Extracts / blood*
  • Plant Extracts / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Water


  • Antioxidants
  • Blood Glucose
  • Insulin
  • Phenols
  • Plant Extracts
  • Water
  • Cholesterol