The clinical impact of an extra virgin olive oil enriched mediterranean diet on metabolic syndrome: Lights and shadows of a nutraceutical approach

Abstract

For years it has been established that the only truly effective treatment of metabolic syndrome (MS) is lifestyle modification to prevent its cardiovascular (e.g., coronary artery disease and atherosclerosis), metabolic (e.g., diabetes mellitus), and hepatic (e.g., steatosis and non-alcoholic steatohepatitis) complications. The focal points of this approach are to increase physical activity and intake of a diet characterized by high quantities of fruits, vegetables, grains, fish, and low-fat dairy products, the so called mediterranean diet (MD); however, the added value of MD is the presence of extra virgin olive oil (EVOO), a healthy food with a 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). Phenolic compounds not only determine EVOO’s main organoleptic qualities (oxidative stability, specific flavor, and taste features) but, theoretically, make it a source of antioxidant, anti-inflammatory, insulin-sensitizing, cardioprotective, antiatherogenic, neuroprotective, immunomodulatory, and anticancer activity. Although many studies have been carried out on EVOO’s clinical effects and attention toward this dietary approach (healthy and palatable food with strong nutraceutical activity) has become increasingly pressing, there are still many dark sides to be clarified, both in terms of actual clinical efficacy and biochemical and molecular activity. Thus, we reviewed the international literature, trying to show the state of the art about EVOO’s clinical properties to treat MS (along with correlated complications) and the future prospective of its nutraceutical use.

Metabolic and molecular effects of dietary extra virgin olive oil in blood and placenta of women with GDM

“…The prevention of the altered insulin resistance markers observed in the GDM patients treated with the EVOO-enriched diet suggests that the EVOO dietary treatment is able to regulate insulin resistance, likely related to the concomitant reduction observed in maternal BMI. Although there are no previous studies addressing the effect of EVOO on insulin resistance markers in GDM, different studies performed out of pregnancy have shown the capacity of an EVOO-enriched diet to reduce parameters related to insulin resistance ( 12 , 49 ). Of note, as stated in our primary study, the nutritional indication to the GDM-EVOO group (3 tablespoons/day) was evaluated by nutritionists at least monthly, and good adherence (over 26 g EVOO per day at least 5 days a week) was reported in 83% of the patients ( 22 ).…”

Oxidative Stress as a Target for Non-Pharmacological Intervention in MAFLD: Could There Be a Role for EVOO?

“…The beneficial effects of MD on MAFLD appear to be directly related to the ability of this dietary approach to modify many of the metabolic pathways underlying MetS, reducing cardiovascular risk and, overall, both morbidity and mortality of these patients [ 104 , 105 , 106 , 107 , 108 , 109 ]. Several studies have hypothesized that, although the effectiveness of the MD is nowadays consolidated, the true added value of this dietary approach in the treatment of MetS is connected to the intake of high doses of extra virgin olive oil (EVOO) [ 110 , 111 ].…”

“…The latter includes more than 30 different molecules: secoiridoids (the largest group, including oleacein and oleocanthal, along with aglycone forms of oleuropein and ligstroside), phenolic alcohols (mainly hydroxytyrosol (HT) and tyrosol (Tyr)), phenolic acids, lignans, and flavones. These ‘minor’ compounds are responsible for several of EVOO’s biological properties and sensory attributes (color, odor, flavor, taste, and aftertaste) [ 110 , 111 ].…”

Beneficial Effects of Plant Oils Supplementation on Multiple Sclerosis: A Comprehensive Review of Clinical and Experimental Studies

“…Olive oil is rich in MUFAs in the form of oleic acid, with a content of 55-83%, but also α-linolenic acid (3-19%), phenolic compounds, sterols, tocopherols, polar pigments (pheophytins and chlorophylls), triterpenic, dialcohols and hydrocarbons, including squalene and the carotene β-carotene and xanthophylls [130]. Olive oil was reported to inhibit foodborne pathogens and stimulate useful microorganisms like L. acidophilus and B. bifidum, which are known as probiotic strains, with potential health benefits after consumption.…”