Impact of Extra Virgin Olive Oil (EVOO) with Health Properties in Metabolic Syndrome

Metabolic syndrome (MS), defined according to the to the revised Adult Treatment Panel III - National Cholesterol Education Program (ATP III - NCEP) criteria,, represents a widespread condition in Western populations (absolute prevalence ranging from 22% to about 33%) and with a trend that increases with time and age (it is expected that its prevalence will increase by about 53% by 2035). MS, not differently from each of the components that characterize it, is a known risk factor for cardiovascular diseases (relative risk (RR) 1.53-2.18) and type 2 diabetes mellitus (RR 3.53-5.17). To date, national and international panels indicate lifestyle modification as the only indication for treating MS and reducing the risk of cardiovascular and metabolic diseases. The increase in daily physical activity and the modification of the diet are therefore the cornerstones of the treatment.

The Mediterranean Diet (MD) represents a traditional value of the Italian population which has shown in several studies a protective effect on mortality and survival free from cardiovascular events. The added value of MD is the presence of extra virgin olive oil (EVOO), a healthy food with high content of monounsaturated fatty acids, especially oleic acid, and variable concentrations (range 50-800 mg/kg) of phenols (oleuropein, ligstroside, and oleocanthal, and their derivatives phenolic alcohols, such as hydroxytyrosol and tyrosol). Olive oil is defined as healthy according to European Commission (EC) Reg. 432/2012. A good EVOO contains about 75% of oleic acid although a variability between 55% and 83% of all fatty acids is expected according to the World Health Organization. The polyphenols content plays a key role in the choice of the type and quantity of oil with health objectives, with particular reference to the unsaturated and polyunsaturated component (oleic acid, linoleic acid, alpha linolenic acid). Phenolic compounds not only determine EVOO main organoleptic qualities (oxidative stability and specific flavor and taste features) but, theoretically, make it a substance with antioxidant, antiinflammatory, insulin-sensitizing, cardioprotective, antiatherogenic, neuroprotective, immunomodulatory and anticancer activity.

Any beneficial substance, including olive oil, goes through a series of biochemical processes before reaching the target organ, by the digestive enzymes and bacteria of the gut microbiota, or the eventual formation of active metabolites after the first liver passage; thus, an exclusively 'in vitro' evaluation of a substance on target cells does not always represent the physiological model of the interaction of these substances with the organism.

The study aims to use a polyphenols enriched EVOO with health properties, derived from different cultivation variants of olives (cultivars), chosen on the basis of preliminary research, coming from Sicilian harvesting campaigns, to evaluate its potential to modify 'in vivo', in subjects with MS, some clinical and laboratory parameters inferring cardiovascular risk, metabolism and inflammation.

Preliminarily, in the phase of the olive harvesting campaigns (three different harvesting periods carried out between November and December: green, mature and advanced ripening), the different indigenous cultivars coming from the same area of Western Sicily (precisely from Val di Mazara, Valle del Belice, Trapani valleys and called Biancolilla, Nocellara, Cerasuolo) will be subjected to biochemical analyses which will aim to identify those with the highest oleic acid and polyphenols content, which will contribute to the enhancement of the specific territory and to the maintenance of biodiversity.

The general objective of the study is to strengthen and enhance the research chain in the nutraceutical and health food sector and the cooperation between the research system and local companies, to support the maximum diffusion and use of new therapeutic substances and advanced technologies for treatment and prevention, and, at the same time, contributing to competitiveness and economic growth by raising the level of scientific-technical skills and knowledge in the production system and in Institutions.

The main objectives of the research, therefore, will be the following:

• Identification and selection of specific autochthonous cultivar able to provide a high quality and polyphenols enriched EVOO.
• Establish potential benefits of a polyphenols enriched EVOO-MD assessing the improvement over metabolic (lipidic and glycemic status), inflammatory (cytokines) and cardiovascular (cIMT and endothelial dysfunction) parameters.
• Establish potential benefits of a polyphenols enriched EVOO-MD assessing the improvement over liver steatosis.
• Analysis of polyphenols enriched EVOO effects on peripheral blood mononuclear cells (PBMC) gene expression exploring their potential use as diagnostic and therapeutic response tool.

Inclusion criteria

• diagnosis of metabolic syndrome according the revised NCEP ATP III criteria; three or more of the following five criteria are met: waist circumference over 102 cm/40 inches (men) or 88 cm/35 inches (women), blood pressure over 130/85 mmHg, fasting triglyceride level over 150 mg/dl, fasting high-density lipoprotein cholesterol level less than 40 mg/dl (men) or 50 mg/dl (women) and fasting blood sugar over 100 mg/dl.
• Hepatitis B virus (HBV) and hepatitis C virus (HCV) negativity.

Exclusion criteria

• alcohol intake (>30 g/day for men and >20 g/day for women);
• acute or chronic hepatic and/or cardiac failure;
• acute or chronic kidney disease (stage G4 Kidney Disease: Improving Global Outcomes (KDIGO) revised classification, glomerular filtration rate <30 mL/min/1.73 m2);
• neoplasms;
• autoimmune or acute and chronic inflammatory diseases;
• acute or chronic infective diseases;
• pregnancy and/or breastfeeding.