Health effects of olive oil polyphenols: Recent advances and possibilities for the use of health claims

The Mediterranean diet and consumption of olive oil have been connected in several studies with longevity and a reduced risk of morbidity and mortality. Lifestyle, such as regular physical activity, a healthy diet, and the existing social cohesion in Southern European countries have been recognised as candidate protective factors that may explain the Mediterranean Paradox. Along with some other characteristics of the Mediterranean diet, the use of olive oil as the main source of fat is common in Southern European countries. The benefits of consuming olive oil have been known since antiquity and were traditionally attributed to its high content in oleic acid. However, it is now well established that these effects must also be attributed to the phenolic fraction of olive oil with its anti‐oxidant, anti‐inflammatory and anti‐microbial activities. The mechanisms of these activities are varied and probably interconnected. For some activities of olive oil phenolic compounds, the evidence is already strong enough to enable the legal use of health claims on foods. This review discusses the health effects of olive oil phenols along with the possibilities of communicating these effects on food labels.     

The influence of olive oil on human health: not a question of fat alone

Olive oil is the most representative food in the traditional Mediterranean diet and its most important source of MUFA. The healthy benefits of MUFA-rich diets on plasma cholesterol levels, were the first to generate interest in this dietary model. In addition to the benefits conferred by its lipids, olive oil has other biological effects, some of them also related to MUFA. However, most recent studies have shown that there are a number of properties that depend on, or are potentiated by, the consumption of olive oil, such as virgin olive oil, that is rich in microcomponents. This foodstuff, thanks to its double set of benefits, thus tends to produce a better lipid profile and a less prothrombotic environment, promoting antioxidant and anti-inflammatory effects, with a greater endothelial protective capacity. In view of these effects, it would appear that when olive oil is the basic source of dietary alimentary fat it has a major antiatherogenic capacity, which is not shared to the same extent by other oils that are rich in oleic acid but lack its characteristic micronutrients.     

Potential of olive oil phenols as chemopreventive and therapeutic agents against cancer: A review of in vitro studies

Olive oil is a common component of Mediterranean dietary habits. Epidemiological studies have shown how the incidence of various diseases, including certain cancers, is relatively low in the Mediterranean basin compared to that of other European or North America countries. Current knowledge indicates that the phenolic fraction of olive oil has antitumor effects. In addition to the ability to be chemopreventive, with its high antioxidant activity, the antitumor effects of olive oil phenols (OO‐phenols) has been studied because of their capacity to inhibit proliferation and promote apoptosis in several tumor cell lines, by diverse mechanisms. This review will summarize and discuss the most recent relevant results on the antitumor effect of OO‐phenols on leukemia tumor cells, colorectal carcinoma cells, and breast cancer (BC) cells. In particular, very recent data will be reported and discussed showing the molecular signaling pathways activated by OO‐phenols in different histopathological BC cell types, suggesting the potential use of OO‐phenols as adjuvant treatment against several subsets of BC. Data summarized here represent a good starting point for more extensive studies for better insight into the molecular mechanisms induced by OO‐phenols and to increase the availability of chemopreventive or therapeutic drugs to fight cancer.     

Phenolic profile and antioxidant activities of olive mill wastewater

Olive trees play an important role in the Moroccan agro-economy, providing both employment and export revenue. However, the olive oil industry generates large amounts of wastes and wastewaters. The disposal of these polluting by-products is a significant environmental problem that needs an adequate solution. On one hand, the phytotoxic and antimicrobial effects of olive mill wastewaters are mainly due to their phenolic content. The hydrophilic character of the polyphenols results in the major proportion of natural phenols being separated into the water phase during the olive processing. On other hand, the health benefits arising from a diet containing olive oil have been attributed to its richness in phenolic compounds that act as natural antioxidants and are thought to contribute to the prevention of heart diseases and cancers. Olive mill wastewater (OMW) samples have been analysed in terms of their phenolic constituents and antioxidant activities. The total phenolic content, flavonoids, flavanols, and proanthocyanidins were determined. The antioxidant and radical scavenging activity of phenolic extracts and microfiltred samples was evaluated using different tests (iron(II) chelating activity, total antioxidant capacity, DPPH assays and lipid peroxidation test). The obtained results reveal the considerable antioxidant capacity of the OMW, that can be considered as an inexpensive potential source of high added value powerful natural antioxidants comparable to some synthetic antioxidants commonly used in the food industry.     

Olive oil and longevity

Several lines of evidence point to olive oil and the olive oil-centered Mediterranean diet as conducive to longevity. The evidence stems from ecological, as well as analytic epidemiological studies assessing olive oil, monounsaturated lipids or the Mediterranean dietary pattern in relation to the incidence of, or mortality from, major common diseases, or overall mortality. Mechanistic considerations are addressed by biochemical studies, whereas randomized clinical trials provide further support to the evidence generated from observational investigations. The content of olive oil in several microcomponents with antioxidant potential, as well as its high content in monounsaturated lipids appear to be essential for the beneficial effect of this food.     

Virgin Olive Oil as Frying Oil

Frying is one of the oldest cooking procedures and is still among the most popular ones for food preparation. Due to their unique sensory characteristics, fried foods are consumed often and with pleasure. During frying, part of the oil is absorbed by the food, thereby becoming part of our diet; most interestingly, in the Mediterranean area approximately 50% of total fat intake is provided by cooking fats. Olive oil is the key lipid component of the Mediterranean diet, the health‐promoting effects of which have been largely attributed to olive oil intake. Olive oil is unique among vegetable oils due to its desirable lipid profile and some of its minor components. Scientific evidence now indicates that during frying olive oil behavior is usually equal or superior to that of refined vegetable oils. Herein, an overview of virgin olive oil performance under frying is given, with special reference to the fate of olive oil microconstituents. The compositional changes of foods fried in olive oil are also reviewed and discussed in detail.     

Olive biophenols: novel ethnic and technological approach

Biophenols are monomeric dihydroxyaromatic moieties that are active non-nutrient components widely found in all plant-derived foodstuffs. Wizened Oinotria table olives (WOTO) and extra virgin olive oil (EVOO), both typical ethnic products of the Mediterranean food culture, are especially rich in biophenols. Table olives can be prepared by traditional methods or by technological processing involving blanching, salting and drying of mature black olives. Olive quality depends on harvesting at mature stages, infestation conditions, firmness, triacylglycerol and biophenol content. The fruit firmness and biophenol content decreases during ripening and processing whereas the triacyiglycerol content increases. Differential scanning calorimetry (DSC) was used to determine the triacylglycerol content in dried olive pulp, and to follow inoliation trends during the production of table olives and extra virgin olive oil. The DSC technique is fast, specific, reliable, uses no solvents and requires lower amounts of olive samples compared to conventional methods. After olive production, triacylglycerol quality was maintained without lipid deterioration. The total biophenol content was sufficiently large to ensure a shelf life and functional value for olive products. Biophenols in olive products demonstrate antioxidant, free-radical antagonism and anti-microbial activity, which are important for human health and well being. Technological innovation, such as EVOO from pitted olives, using ancient methods, can continue to be at the forefront of development in the olive agrifood chain. Creativity and sophisticated techniques will provide new perspectives for olive manufacturing, based on typical regional and ethnic products. The nutritional, sensory and functional enhancement of traditional olive foods, offer the potential for improving human health and well being within the context of the Mediterranean diet.     

Olive oil and the haemostatic system

Interest in the Mediterranean diet (MD) has grown worldwide due to its link with greater longevity and lower cardiovascular disease rate, cancer and age cognitive decline. Despite the high complexity of its nutrients composition, olive oil emerges as its principal food, since it provides the higher percent of energy and a lot of bioactive compounds. In this review we will discuss the benefits of diets enriched in virgin olive oil, whose effects are probably due not only to its oleic acid content but also to its other potentially health-promoting components. Traditionally, the benefits of MD were linked to its effect on lipoprotein metabolism but today we realise that there exists a whole sheaf of other benefits, including the components of haemostasis: platelet function, thrombogenesis and fibrinolysis. A diet enriched in virgin olive oil can reduce the sensitivity of platelets to aggregation, decreasing von Willebrand and tromboxane B2 plasma levels. Moreover a particular interest has arisen about its capacity to decrease fasting Factor VII plasma levels and to avoid or modulate its postprandial activation. Also Tissue Factor expression in mononuclear cells could be reduced with the chronic intake of virgin olive oil and finally, studies performed in different experimental situation have shown that it could also increase fibrinolytic activity, reducing plasma concentration of Plasma Activator Inhibitor type-1.     

Biological properties of olive oil phytochemicals

Olive oil is the principal source of fat in the Mediterranean diet, which has been associated with a lower incidence of coronary heart disease and certain cancers. Extra-virgin olive oil contains a considerable amount of phenolic compounds, for example, hydroxytyrosol and oleuropein, that are responsible for its peculiar taste and for its high stability. Evidence is accumulating to demonstrate that olive oil phenolics are powerful antioxidants, both in vitro and in vivo; also, they exert other potent biological activities that could partially account for the observed healthful effects of the Mediterranean diet.     

Intervention studies on Mediterranean diet and cardiovascular risk

The traditional Mediterranean diet, as studied in the 1950s to 1960s in the South of Europe, is characterized by moderate energy intake, low animal fat, high olive oil, high cereals, high legumes, nuts and vegetables, and regular and moderate wine. A Mediterranean-type diet is being developed to mimic the traditional one and fit with present life style. While numerous epidemiological studies have supported the concept that adherence to the traditional Mediterranean diet is beneficial for health and particularly protects against cardiovascular disease, the limited number of intervention studies in this field have not yet provided major support. Nevertheless, the dietary interventions performed until now have demonstrated that adoption of a Mediterranean-type diet reduces several cardiovascular risk factors in subjects at risk (primary prevention) and/or cardiovascular events or mortality in patients after a first cardiac event (secondary prevention). Among numerous foodstuffs characterizing the Mediterranean diet, virgin olive oil has been shown to display beneficial effects on a wide range of risk factors.     

Relevance of functional foods in the Mediterranean diet: the role of olive oil,berries and honey in the prevention of cancer and cardiovascular diseases

Abstract

The traditional Mediterranean diet (MedDiet) is a well-known dietary pattern associated with longevity and improvement of life quality as it reduces the risk of the most common chronic pathologies, such as cancer and cardiovascular diseases (CVDs), that represent the principal cause of death worldwide. One of the most characteristic foods of MedDiet is olive oil, a very complex matrix, which constitutes the main source of fats and is used in the preparation of foods, both raw as an ingredient in recipes, and in cooking. Similarly, strawberries and raspberries are tasty and powerful foods which are commonly consumed in the Mediterranean area in fresh and processed forms and have attracted the scientific and consumer attention worldwide for their beneficial properties for human health. Besides olive oil and berries, honey has lately been introduced in the MedDiet thanks to its relevant nutritional, phytochemical and antioxidant profile. It is a sweet substance that has recently been classified as a functional food. The aim of this review is to present and discuss the recent evidence, obtained from in vitro, in vivo and epidemiological studies, on the potential roles exerted by these foods in the prevention and progression of different types of cancer and CVDs.     

Phenolic compounds in olive oil and olive pomace from Cilento (Campania,Italy) and their antioxidant activity

Virgin olive oil (VOO) has nutritional and sensory characteristics that make it unique and a basic component of the Mediterranean diet. Its importance is mainly attributed to its richness in polyphenols, which act as natural antioxidants and may contribute to the prevention of several human diseases. In this paper we report the determination and quantification of oleocanthal, one of the main substances responsible for the bitter taste of olive oil, together with a quali-quantitative analysis by HPLC analytical methods of phenolics from Cilento VOO and olive oil pomace. The total phenolic content was also determined and the in vitro antioxidant and free-radical scavenging activities by DPPH test was evaluated. A superoxide anion enzymatic assay was also carried out and the results were confirmed by the inhibition of xanthine oxidase activity assay. The possible protective role played by VOO secoiridoids on injurious effects of reactive oxygen metabolites on the intestinal epithelium, using Caco-2 human cell line, was investigated.     

The Historical Development and Nutritional Importance of Olive and Olive Oil Constituted an Important Part of the Mediterranean Diet

The olive tree (Olea europaea) is widely cultivated for the production of both oil and table olives and very significant because of its economic value. Olive and olive oil, a traditional food product with thousands of years of history, are the essential components of the Mediterranean diet and are largely consumed in the world. Beside of their economical contribution to national economy, these are an important food in terms of their nutritional value. Olive and olive oil may have a role in the prevention of coronary heart disease and certain cancers because of their high levels of monosaturated fatty acids and phenolic compounds. In addition, olives (Olea europaea L.) and olive oils provide a rich source of natural antioxidants. These make them both fairly stable against auto-oxidation and suitable for human health. The aim of this paper is to define the historical development and nutritional importance of olive and olive oil constituted an important part of the Mediterranean diet.     

Estimation of the intake of phenol compounds from virgin olive oil of a population from southern Spain

The objective of the study was to determine the mean polyphenol composition of different varieties of virgin olive oil (VOO) habitually consumed in the region of southern Spain and to estimate the dietary exposure to olive oil polyphenols in that population. There were statistically significant differences in total polyphenols among varieties, with the Picual variety containing the largest amount with a mean value of 591.8 mg kg^–1. The main phenolic compounds found in the VOOs under study were tyrosol and hydroxytyrosol. The highest amounts of both substances were found in Picual olive oils with concentrations of 2.3–6.6 mg kg^?1. The total intake of polyphenols from VOO ranged between 8.2 mg day^–1 (SD = 4.14) for the under 19 year olds and 21.3 mg day^–1 (SD = 3) for the over 50 year olds. Some polyphenols, including tyrosol and hydroxytyrosol, were consumed principally as olive oil. The intake of these compounds in the studied population was in the range of 88.5–237.4 μg day^–1. This has particular importance as recent studies have demonstrated that hydroxytyrosol helps to improve plasma lipids levels and repair oxidative damage related to cardiovascular disease. There was a greater dietary consumption of polyphenols in olive oil among the participants who more closely followed the Mediterranean diet pattern. A higher consumption of olive oil and therefore a greater exposure to polyphenols was observed in females versus males and in participants of normal weight versus those who were overweight. The total intake of polyphenols from VOO significantly increased with higher age, reflecting the greater intake of this oil by older people, who also show a closer adherence to the Mediterranean diet. The over 50-year-old age group showed the greatest consumption of this olive oil and therefore of phenolic compounds, which are healthy protectors in the human diet that contribute to the acknowledged benefits of the Mediterranean diet.     

Melatonin is a phytochemical in olive oil

Given the numerous observations regarding the positive effects of olive oil consumption and the presence of melatonin in edible plants, we addressed for the first time the question of melatonin determination in virgin olive oil. All the extra virgin olive oil registered designation of origins from Spain and commercial samples of refined olive and sunflower oil were used. Immunoprecipitation and ELISA were combined for melatonin determination. Melatonin is present in olive oil at higher levels in extra virgin olive oil than in refined olive or sunflower oil samples. We concluded that melatonin is part of the phytochemical profile of the olive oil. Particularly, extra virgin olive oil had almost double the melatonin contents of the other refined oils analysed. Thus, melatonin may account for the healthy effects of the Mediterranean diet in which olive oil is the main source of fat.     

Olive oil and oxidative stress

Oxidative stress is defined as an imbalance between the oxidant and antioxidant systems of the body, in favor of the oxidants. Oxidative stress produced by free radicals has been linked to the development of several diseases such as cardiovascular, cancer, and neurodegenerative diseases Olive oil is the main source of fat of the Mediterranean diet which has been shown to be effective against oxidative stress associated diseases and also with ageing. Besides its richness in monounsaturated fatty acids, the oleic acid, olive oil contains minor components with antioxidant properties. In this review, we summarize the state of the art, and degree of evidence, of the body of knowledge concerning the protective role of the major and minor components of olive oil on oxidative stress.     

酶处理对初榨橄榄油品质及抗氧化活性的影响

将纤维素酶、果胶酶应用于橄榄油提取工艺,旨在生产具有较高总酚含量及较强抗氧化活性的高质量初榨橄榄油。随着果胶酶和纤维素酶添加量的提高,橄榄油的过氧化值及K_(232)均出现下降的趋势,油酸比例有一定程度提高,并在添加0.2%纤维素酶时油酸比例达到最高(65.85%)。结合主成分分析,确定了在油橄榄融合过程中添加0.5%纤维素酶得到的初榨橄榄油总酚含量和抗氧化活性最高。这是由于果胶酶和纤维素酶能有效降解橄榄细胞壁,减少亲水酚类物质与细胞壁多糖的络合,有助于橄榄果皮中的游离酚的释放,从而提高橄榄油中总酚含量及抗氧化活性。     

Beneficial properties of olive oil

The Mediterranean diet is reputed to account for the lower incidence of coronary heart disease (CHD) in southern Europe. Olive oil is the principal source of fat in the Mediterranean diet, therefore the southern European diet contains more monounsaturated fatty acids (MUFA) and less saturated fatty acids (SFA), compared to the Northern European diet. Atherosclerosis and thrombosis are the two key pathophysiological processes which lead to the development of CHD. Therefore, the aim of the EU project entitled “The Beneficial Properties of Olive Oil” was to investigate how olive oil mediated its protective effect against CHD. The project had two parts, phase I involved a cross-cultural comparison to investigate the effect of a habitual southern European diet which is rich in olive oil compared to the northern european diet which contains little or no olive oil on a range of CHD risk factors. In phase II, a dietary intervention study was designed to substitute dietary SFA with MUFA, derived from olive oil, in the usual diet of free-living northern European men to investigate if this dietary change affected indices of CHD risk.     

Involvement of oleuropein in (some) digestive metabolic pathways

Olive oil is the principal source of fats in the Mediterranean diet and it has been postulated that the components in olive oil can contribute to a lower incidence of coronary heart disease and cancers (prostate, colon, breast, and skin). The positive effects on human health can be attributed to the high level of phenolic compounds present in olive oil, the major ones being oleuropein, hydroxytyrosol and tyrosol. The aim of the present study was to evaluate the effect of oleuropein on enzymes involved in specific pathways of metabolism of proteins, carbohydrates and lipids.In particular, the effects of oleuropein on enzymes, such as trypsin, pepsin, lipase, glycerol dehydrogenase, glycerol-3-phosphate dehydrogenase, and glycerokinase, were investigated.Results demonstrate that oleuropein is able to activate pepsin and shows an inhibitory effect toward all the other enzymes tested, which suggests a new role for this polyphenol. In addition, a new method for lipase activity assay is presented.     

NMR spectroscopy: a powerful tool for the analysis of polyphenols in extra virgin olive oil

Extra virgin olive oil (EVOO), a key component of the Mediterranean diet, has aroused interest in recent years due to its health properties. Nuclear magnetic resonance (NMR) spectroscopy is an appropriate tool for the accurate quantification of minor compounds in complex food matrices, such as polyphenols in olive oil. Flavonoids, lignans, secoiridoids and phenolic acids and alcohols in EVOO have been identified and quantified by NMR. This review provides an overview of the major developments in the structural elucidation of polyphenol compounds in EVOO. © 2019 Society of Chemical Industry