Olive Oil and Health
Is Olive Oil a Medicine?
Olive oil is not a medicine, however, the protective/supportive effects of the compounds it contains on human health are supported by more and more scientific data day by day. Research data showing that these effects are more preventive/protective than treatment are increasing.
Is Olive Oil a Functional Food?
Today's people have become more concerned with the chemical or biological principles that determine the nature, content and effects of the foods they eat on the body than in the past. Our diet is the source of our biological building blocks as well as a source of energy. The fact that olive oil is the primary source of fat can affect the metabolic functions of multiple organ systems, especially the digestive system, contribute positively to organ functions, and increase the bioavailability of other foods. The molecules in its content, the derivatives of these molecules or the complexes they form, enable the nutrients to be absorbed more effectively from the digestive system. In terms of gastronomy, olive oil is considered as a "functional food" due to the different components it contains. The compounds that give this characterization to the oil are mostly found in the first quality olive oils, which are called "extra virgin".
The most important components of olive oil, which cause it to be qualified as a functional food, are highly monounsaturated fatty acids, polyphenolic compounds characterized as organoleptics, plant-derived natural chemicals such as alpha-tocopherol and squalene.
Unfortunately, most of the natural oils of vegetable origin, except extra virgin olive oil, cannot be brought into a state of consumption without being refined, that is, without losing their organoleptic components.
Relationship Between Olive Oil Consumption and Health
There was a widely accepted belief that the people of the Mediterranean geography were healthier, had less chronic diseases, and lived longer. Studies comparing the population data of European countries and Greece revealed that Greeks lived on average at least 10 years longer, with the difference being even greater on the islands. This fact has focused research on how to explain this difference. The fact that mortality rates from cardiovascular disease and cancer are lower in the peoples of this geography led to the research of the region and their lifestyles. Since the beginning of 2000, many epidemiological studies (examination of the distribution of human health-related conditions in the society, their incidence and the markers affecting them) have drawn attention to the inverse relationship between death rates due to chronic diseases and the intake of antioxidant-containing vegetables and fruits, especially in Mediterranean countries. It was published. The possible positive effects of plant-derived natural chemicals in olive oil on human fat metabolism were first explained at the "First International Olive Oil and Health" conference held in Spain in 2004. In 2004, the US Food and Drug Administration (FDA) approved the health benefits of virgin olive oil to be written on the packaging. Later, this policy was also accepted by the European Union and Canada. The definition of “Mediterranean diet”, which is used to express the eating habits of the peoples of the Mediterranean basin, has been a popular definition frequently used over the past decades. In 2010, the “Mediterranean Diet” was recognized by UNESCO as the “Intangible Cultural Heritage of Humanity”.
Our genes play a role in all phases of the emergence, development, progression and finalization of chronic diseases (obesity, diabetes, high blood pressure, some types of cancer, etc.). These functions of our genes can be modified through our diets. The diet and environment used are the factors that determine the balance between the person's health or disease status, depending on the genetic makeup of the person. Scientific studies have shown that there is a direct or indirect relationship between food and gene expression.
Olive-derived components in the content of first quality/extra-virgin olive oil play a role not only against the oxidant effects we are exposed to from the external environment, but also in neutralizing the internal free oxygen radicals that occur during the activities of the organism and are even most responsible for our aging.
How Do the Ingredients in Olive Oil Function?
Oxygen, which is our basic need for life, mixes with the blood through the lungs and is delivered to our cells in the blood cells and tissues. After functioning and being metabolized inside the cell, some of this oxygen turns into molecules called "free radicals" inside the cell. These free radicals, which are formed in all living things that metabolize oxygen, do not only emerge as a result of the oxygen metabolism processes that take place in the body, but also; They also occur as a result of biochemical processes associated with external factors such as ultraviolet rays, radioactivity, ozone, environmentally harmful substances, cigarettes and drugs. Human metabolism has mechanisms that control these free radicals, however; The amount of free radicals increases as a result of the deterioration of the balance or the insufficiency of these mechanisms.
If the oxidative stress cannot be eliminated by the cell's defense mechanisms, the fatty acids in the cell membrane react with these free radicals, this reaction is the beginning of a destruction process called "peroxidation". In human biology, many evidence-based studies have shown that the damage caused by this abnormal state, which occurs at the cellular level, is associated with an increased risk of cardiovascular diseases, cancer and certain chronic diseases.
There are natural protective substances formed by our body as a defense mechanism against the harmful effects of free radicals. However, researches have shown that the defense systems originating from the organism are not sufficient for the removal of oxygen radicals. In addition, it has been determined that some molecules taken from the outside can have a very protective function against oxidative damage in the organism. These molecules are called "antioxidant" and their function of scavenging free radicals is called "antioxidant capacity".
Phytochemicals found in vegetables and fruits that we frequently consume have antioxidant capacity. They perform these functions in more than one way, some of them capture free radicals directly, some activate enzymes that remove the negative effects of free radicals. In addition; They can stimulate the immune system, affect genes related to cell proliferation and programmed cell death, and are also effective by regulating hormone metabolism and antibacterial and antiviral effects. Some vitamins, minerals, enzymes can be given as examples. Contrary to what was previously thought, it has been understood that the use of one or more antioxidants such as vitamin A or E alone is insufficient to protect from chronic diseases, and it is necessary to use the compounds called phytochemicals with antioxidant effect in their natural state, without cooking and regularly.
Extra virgin olive oil has multiple compounds with organoleptic properties that scavenge free radicals, therefore considered powerful antioxidants.
Which Antioxidant Compounds Does Olive Oil Contain?
The "monounsaturated fatty acids", classified as the major component, are the antioxidant compounds most abundant in the content of extra virgin olive oil. The positive effects of olive oil on human health are generally associated with its high content of monounsaturated fatty acids (oleic acid, palmitic acid, etc.).
Especially oleic acid is a molecule resistant to the negative effects of oxygen, its high content also contributes to the antioxidant properties, high stability and long shelf life of olive oil.
The antioxidant activity of oleic acid and phenolic compounds in olive oil has been demonstrated in both laboratory and human studies.
It has been proven that the compounds it contains with regular consumption in the diet reduce LDL cholesterol and triglyceride levels. This potential in olive oil is thought to be related to the development of less atheroma plaque (hardening of the arteries). Another study has published findings that it can prevent non-alcoholic fatty liver disease.
Triterpene alcohols suppress cholesterol synthesis and have vasodilating properties.
Hydrocarbons have protective effects in cholesterol level control, skin functions and cancer development.
One of the biological supports provided by olive oil is the sterols in its content, these plant-derived compounds called phyto-sterols are found in many different kinds of vegetable-derived oils, cholesterol-like compounds, they reduce the reabsorption of cholesterol from the intestines by increasing the effectiveness of bile. These sterols and other aromatic minor components with organoleptic properties stimulate digestive enzymes from the stomach and increase bowel movements, creating an effect that regulates the digestive system.
In the laboratory environment, studies on breast and colon cancer cells have revealed some protective effects. With this; Its effects on cancer cells in humans have not yet been fully defined.
The components that are classified as minor components and that have proven positive effects on health are squalene, alpha-tocopherol and phenolic components (hydroxytyrosol, oleuropein).
Squalene is an important intermediate in the biosynthesis steps of cholesterol, it is present in olive oil in large proportions compared to other foods, and it has been proven to have a preventive effect against cancer. It is found mostly in the skin of the human body. For this reason, it is thought to play a role as a part of the body's protection mechanism in skin tissue exposed to ultraviolet radiation from the sun. It has been shown to have a preventive effect against skin cancer in animal experiments. There is an opinion that it has an effect on the lower incidence of human skin cancer in the Mediterranean region. In addition, its protective effects in cancers originating from large intestine cells and fatty liver have been demonstrated by laboratory studies. Although these cancer-related data are skeptical, the increase in cancer incidence observed in many other oils, especially animal-derived saturated fats, has not been observed in olive oil, at least.
Olive oil is the richest oil among vegetable oils in terms of squalene molecule content. Recently, studies on it have started to increase due to its protective function against cancer, and its amount decreases in refined olive oil. It has been found in nature to be most abundant in shark liver, and there is increasing evidence that it is found in greater amounts in olive oil from ripe olives.
Tocopherols show similar activity to vitamin E, olive oil is the product with the highest alpha-tocopherol content among vegetable oils, it comes after green leafy plants in terms of vegetable-derived vitamin K content. The main form of vitamin E found in olive oil is αlpha-tocopherol, which accounts for approximately 95% of total tocopherols. Alpha-tocopherol, known as the active form of vitamin E, is highly resistant to oxidative degradation. However, the presence of polyunsaturated fatty acids is essential for the absorption of vitamin E, which is a fat-soluble vitamin, and the ratio of such fatty acids in olive oil is very low.
Despite its presence in relatively low concentrations in olive oil, regular daily consumption of olive oil has been shown to increase the overall antioxidant content in the human body, contributing to cells being more resistant to oxygen-induced damage. In addition, it is known that such antioxidants taken from outside contribute to the protection against degenerative diseases by increasing the level of existing antioxidants in the body.
Phenolic compounds (polyphenols) are recognized as a micronutrient that is the natural equivalent of vitamin E. The origin of the word is the ancient Greek language; It is derived from the combination of the word “Pollus”, which means many, and the words phenol. The main phenolic compounds detected in olive oil and the amount of which is known; It takes place in three groups as simple phenols (hydroxytyrosol, tyrosol), secoiridoids (oleuropein) and lignans. It has been shown that polyphenols are a molecule that supports the defense mechanisms of the cell against molecules that are formed by the metabolization of oxygen in the cells and have destructive effects for the cell in the laboratory environment. Therefore, all polyphenols are considered to have antioxidant properties. These molecules contribute to the unique taste of the oil, are among the most researched components, increase the resistance against free oxygen radicals that occur as a result of normal cell metabolism processes, and support the biological defense mechanisms that prevent cells from turning into cancer cells.
In contrast to oil-soluble compounds such as tocopherols, water-soluble phenolic compounds in extra virgin olive oil have also been reported to be highly correlated with oxidative stability. Olive oil contains more than thirty phenolic molecules. There are more than one laboratory method for the measurement of phenolic compounds in its content, and the amounts measured with each method may be different. There is a consensus that there is an average of 230 mg of total phenolic compounds in one kilogram of olive oil. The amount of phenolic compounds in olive oil is related to more than one factor; The most important ones are the environmental growth conditions of the olive, the production method of the oil and the storage conditions.
The phenolic compounds found at the highest rate in olive oil are lignans, followed by oleuropein and hydroxytrizole. Hydroxytrizole is found in the leaves of the olive as well as the fruit. Pomace and olive black juice, which are produced as residues in the process of obtaining oil, have a higher polyphenol content than olive oil, therefore; Recently, it has been observed that there has been an increased interest in the use of olive leaf, pomace and olive black water.
Compared to vitamins C and E, the polyphenols in olives have been shown to be more effective in preventing the deterioration of the integrity of fats and proteins by oxygen, which is called peroxidation. It has been shown that olive oil forms membranes that are more resistant to peoxidation, in particular, and is more functional compared to membranes formed with polyunsaturated oils such as sunflower oil. It has been shown that olive oil has a higher antioxidant capacity than other vegetable oils, and the antioxidant compound ratio is higher in extra virgin olive oil than in refined virgin olive oil. In a study; The risk of developing obesity within 6 years was found to be 2.3 times higher in those consuming sunflower oil as cooking oil than in those consuming olive oil.
Oleocanthal is another organic (tyrosol ester) compound isolated from extra virgin olive oil and related to oleuropein. It has been reported that oleocanthal, which also has antioxidant properties, interestingly shows an ibuprofen-like anti-inflammatory effect (inhibiting inflammatory reaction). Long-term consumption of small amounts of oleocanthal in olive oil may be partially responsible for the lower incidence of heart disease associated with the Mediterranean diet; It is claimed that an average of 50 g of olive oil consumed per day has a similar effect to 1/10 adult ibuprofen dose.
Some carotenoids, which are among the minor components of olive oil, also have antioxidant effects, the most abundant ones in the content of the oil are beta-carotene and lycopene, which are also responsible for the color of olive oil. It has been reported that beta-carotene levels in the range of 0.33-3.69 mg/kg in extra virgin olive oil obtained from ripe olives can reach 10 mg levels depending on some factors.
Although the protective effects of phenolic compounds against cancer are not known for certain, there is an opinion that they may reduce the risk of cancer, especially since they have the potential to slow down the cells at various stages in the process of transforming into cancer cells. It has been reported that polyphenols such as hydroxytyrosol and oleuropein can slow proliferation and induce apoptosis in colorectal cancer cell types. The results of a large study suggested that olive oil consumption was inversely related to the risk of developing cancer, especially breast and digestive system. The results of another study conducted in the Canary Islands showed that olive oil consumption has a protective effect against breast cancer. Attention is drawn to the role of minor bioactive components such as squalene and phenolic antioxidants, as well as the oleic acid found in extra virgin olive oil, in the low risk of cancer development. Although it is estimated that there is an annual consumption of olive oil per capita of about 15 kg in Mediterranean countries, when considered in terms of breast cancer, it has been suggested that olive oil has the highest protective effect at a daily consumption of ≥ 30.5 g in women.
In addition to the molecules mentioned above, olive oil also contains beta carotene and hydrophilic phenolic compounds, which are the precursors of vitamin A, which are known to have positive effects on human health.
Could Olive Oil Be a Medicine?
Bioactive phytochemicals related to human health in the content of olive oil; It is related to more than one factor such as the type of olive, the way it is grown, the time of harvest, the technology used during the separation of the oil and the storage conditions. Research continues on the concentrations of these molecules in fat and what kind of diet they should be consumed.
There is a consensus based on evidence-based data that extra virgin first quality olive oil is a healthy food and that its regular consumption every day for a long time has the potential to protect human health from chronic diseases.
However, extensive clinical studies with the participation of large numbers of subjects should be planned on how it functions in human cell metabolism after oral ingestion.
Further evidence-based and detailed research on the underlying molecular mechanisms, especially at the cellular level, should be conducted on the potential therapeutic potential of the bioactive components in its content.
Compiled by: Uğur Saraçoğlu (ugisaracoglu@yahoo.com.tr)
Resources:
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