What exactly is Extra Virgin Olive Oil?

Italy, which produces nearly a third of the world's olive oil, is distinguished by the superior class of its extra virgin, made in all regions of the centre and south and in a few places in the north.

The most flavourful and wholesome of edible oils is used raw in dressings or as a condiment for salads, vegetables, pastas, soups, seafood and meats. Chefs find Extra Virgin unmatchable in cooking because it can reach high temperatures before, despite the higher cost. The best oils show distinct character due to terrain and climate, the varieties of olives they come from and methods of harvesting.

Hand picking of under-ripe olives renders oil of deep green colour, fruity aroma and full flavour (sometimes a touch piquant). Mature olives make oil of paler colour and subtler flavour. Traditional extraction by stone crushing and mat pressing is practiced mainly in mills in Tuscany and Umbria, where oil is especially prized, though most is processed by mechanical mashing and centrifuging.

By law, Olio Vergine di Oliva must come from the first pressing of olives by mechanical (not chemical) means and must contain low percentages of oleic acids - please see the table below for the exact differences between the oils.
 

What does "Cold Press" mean?
Logically first cold press extra virgin olive oil means that the olive oil has been produced without elevated temperatures. This method of stone grinding and pressing without adding chemicals nor allowing the temperature to rise excessively (by Italian law no more than 30 degrees Celsius for the cold press) is ancient and was used already by the Romans and the Greeks who hadn't of course the means to treat their product any less naturally.
It still remains the most natural and less interfering with the composition of the oil, thus the oil keeps its monounsaturated fats and also keeps in tact other beneficial elements such as the antioxidants and vitamins.
This method that hereon will be referred to as "traditional" also guarantees the purest and tastiest product as no other element will interfere with the actual quality of the oil.

Steps of the process of obtaining the oil and our criteria of choosing oils for you:
Step 1: Olives are hand picked after about 120 days after the flowering of the trees. In Tuscany this usually means the beginning or mid November, depending a little on the year. A tree produces different quantities of olives every year all depending on pruning, weather, varietals, age, etc.
Step 2: The contents of the baskets of the olive groves will be put into a separator that will separate the greenery from the olives and the olives will get washed. Olives are gently and slowly mashed by a stone wheel (granite) to a thick paste.
Step 3: The paste is spread on mats made of nylon that are subsequently placed on metal plates. The metal plates are stacked one on top of the other and when the stack is complete it is introduced into the press that will press the olive paste at about 350-450 atmosphere for little more than half an hour.
Step 4: In this manner the liquid is separated from the solid parts (pit and pulp). The liquid coming from the pressing, called must, contains water, oil and small bits of flesh and skin which will be eliminated by a process similar to decanting.
Step 5: The "new" oil is obtained and will be kept in storage in stainless steel tanks at a low temperature (10 degrees Celsius). During the first month the oil will settle and obtain a clear golden color. In Tuscany olive varietals allow 10-15% olive oil per 100 kilos of olives using the cold press traditional technique.
Step 6: The dry parts left over after the pressing and obtaining the olive oil are called "sansa" in Italian and contain 3 elements: more oil (but not of first quality), the pit parts and the skin parts. A lot of olive oil mills sell this part to a "sansificio" that separates the sansa in 3 products: "olio di sansa" is obtained by heating up the mass and adding chemicals (this oil is separated in different qualities depending on its acidity but is really only recommended for the production of soap!), the pit/wooden parts are dried and can be burnt in burners to heat houses, and the skin part are sold to animal food factories.

Cold press extra virgin olive oil is highly recommended in its raw use, so to enhance the flavor of all plates as done in Italy: add a bit of olive oil before serving most anything. Use the oil for your bruschetta, fettunta, salads (together with good vinegar, salt and pepper), etc.

How does Cold Press olive oil distinguish itself in the taste?
First of all, olive oil should remind you of the taste of olives. Cold press means that the olfactory qualities of the oil haven't been modified by heat or other additives such as certain chemicals that are in the big commercial industries to extract more oil. The new oil is always a bit stronger in flavour, and might remind you of artichokes and sometimes has a hint of spicyness. A good cold press oil is rather delicate in taste and has an almondy aftertaste.
What could compromise the quality of a Cold Press Olive Oil:
- Sometimes a cold press oil can have an off taste if the olives were picked either too early (green) or too late (black)
- or maybe cleanliness wasn't a big consideration
- or maybe the leaves were left in the crusher (releasing chlorophylls in the oil)
- maybe the olives were lying around for too long before being pressed (causing oxidization or even fermentation)
- Sometimes the declared "Cold Press" wasn't as cold as it should have been, but since it is not easily controlled someone might get away with declaring it anyway.
Olive oil in Italy is not declared "cold press" on the label, which does not make it any easier for the unknowing consumer. The label will, however, indicate that the oil was obtained uniquely by means of mechanical procedures (as opposed to chemical). This is not much of a guarantee of the real quality of the oil, though, nor whether the oil was obtained by cold press.
Helping the consumer, some regions have now got some kind of control with the introduction of DOPs and IGPs (protected foods from specific regions), but the problem is that these designations cover very small areas compared to the many, many olive oils from different areas and the few traditional producers who might not be in one of these designations - or who's production is simply too small to go through the bureaucratic procedures of obtaining a certification.

So, the mission of TUSCANY IN A BOTTLE is to select for its privileged clients the "true" Cold Press olive oils of Tuscany produced in the traditional way - oils that hardly even make it to the local market as they are rare and normally produced in very limited amounts and only sold locally to the connoisseur who seeks them out. We will select a small quantity of different oils and that may be ordered in small quantities at any time of year. Shipping will take place from December to February every year, when the oils are fresh and new - also the best time to ship for the shipping temperature!

OLIVE VARIETALS

Blended versus Single Variety

Some oils are blended from several olive varieties to produce a unique taste, much like a vintner blends grapes to make a fine wine. Some olive oil producers press oils from a single estate or a single variety, which may produce a fine oil. These single-estate oils and artisan oils are among the world's best, and are always available in very small quantities.

In Italy there are hundreds of different olive oil varieties, the primary Tuscan ones being:

FRANTOIO

Frantoio is the main variety in the national olive oil production. Frantoio olives are cultivated in the centre of Italy, regions of Tuscany and el Marche, as well as throughout the south in the Apulia, the main olive oil producing region of Italy.

Currently the Frantoio variety occupies more than 250.000 acres and is one of the most popular varieties in new olive plantations around the world.

Frantoio olive oil can be characterized as very fruity with a wonderful aroma. As well as being extremely fruity the oil also has a hint of green apple, with a scent of green leaves and grass, a small bitterness and more so pungent flavour, although nonetheless the sensation which this olive oil leaves is sweet, somewhat astringent and an almond flavour.

The intrinsic composition of Frantoio olive oil presents a medium-high content of oleic acid, with a medium content of linolenic and palmitoleic acid. The stability of Frantoio olive oil in becoming rancid can be considered average.

LECCINO

Leccino olives are cultivated in all the major olive growing regions of Italy. They are considered as an expanding variety, and the second most important variety in Italy.

Leccino olive oil has a slight fruitiness, barely bitter and pungent, somewhat sweet and of a light colour.

The intrinsic composition of Leccino olives shows a medium-high content of oleic acid, monounsaturated and of nutritional interest. The levels of palmitoleic and linolenic acid in Leccino olive oil can be considered medium. The stability of Leccino olive oil can also be considered medium level.

MORAIOLO

Variety cultivated in the region of Tuscany, la Umbria, the Marche and in the Abruzzos. Usually cultivated alongside Frantoio olive groves in order to make a composition with both oils.

Has a good level harmonic fruitiness, green apple taste, slightly bitter and pungent although balanced with a nice sweet sensation in the mouth. Slightly astringent with an almond flavour and grassy aroma.

In a Moraiolo’s intrinsic composition we encounter a medium content of oleic acid, high content of palmitoleic and medium-high content of linolenic acid. The stability of a Moraiolo olive oil can be considered low.

The quality and the purity

Olive Oil is for its most part formed by glicerids (95-99,7%) and by minor compouds (0,3-5%) that have a fundamental role, both from a nutritional and organoleptic and from an analytic point of view, as it is possible to detect the biological provenence and to classify product.

For the consumer what is really important when choosing an olive oil to consume, is the quality and purity of the product. As previously seen on this web-site there are certain parameters that determine whether an oil can be classified as an Extra Virgin or other. However, it is not as simple as taking its acidity content. So this page is for whom wants to go into detail on how the quality and purity of an oil can be detected. Most of the information is from the ONAOO (the National Organization of Olive Oil Tasters). But first of all, let's see what is meant by quality and purity.

The intended meaning of Quality is “the totality of requisites and functions of the aliment which can satisfy the consumer’s needs”. Hereunder we can place sensory characteristics, stability to oxidation, absence of xenobiotics, nutritional values (e.g. essential fatty acids, relationship between saturated fatty acids, mono- and polyunsaturated fatty acids etc.), natural antioxidants etc.
The Purity of an aliment refers to the fact that “it has not been subjected to technologies different from those traditionally used, nor has any substance extraneous to its nature been added”. It is evident that a large part of the aims of the EC Regulations is dedicated to ascertaining the purity of olive oils which, due to their high cost, are the object of illegal practices. One single analysis is not yet available which can establish unequivocably the purity of an oil.
 

Tests on quality

1. The oleic acid percentage is one of the factors that determines the quality of an olive oil and it can easily be measured by the means of titration. The lower the quantity of oleic acidity contained in the oil, the better. To obtain a product which is organoleptically better and which has lower acidity, it is necessary to use an olive which is at the right maturation and to process it quickly after harvest. Micro organisms that grow on the fruit produce enzymes that increase the acidity. Hereunder a figure that shows the molecule compound of the fatty acids found in olive oil:
 

2. The content of peroxides in the oil under examination is expressed by the peroxide value. The higher the number, the greater is the degradation due to oxidation of the oil. In their turn the peroxides are subject to further oxidation which gives rise to the formation of other compounds which are determinable in different ways (aldehydes, ketones etc.) These compounds, called compounds of secondary oxidation, are responsible for making the oil rancid. Because of oxidation and due to the enzymes present in the tissue of the fruit (lipoxygenases), a certain concentration of peroxides is already present in the fruit before pressing. Particular natural circumstances (e.g. temperatures below freezing, dacic infestations, drought etc.), or olives incorrectly harvested and preserved may encourage a further formation of peroxides. Even during milling peroxides can increase greatly through bad processing or due to incorrect hygiene in the olive-press and/or of the vessels. Finally, prolonged exposure of the oil to light or heat sources is another cause of the increase of peroxides. The content of peroxides are determined through titration.
In this context it makes sense that we are told that olive oil should be consumed within two years of its production, it should be kept in a cool and dark place to preserve its organoleptic qualities.

3. In addition to these chemical analysis, a sensorial evaluation (panel test) should be carried out.

Tests on purity

The tests that prove purity are many and strictly chemical. Here's a list of the ones that have been found necessary to determine the pureness of an olive oil, or even better to exclude the probability that an olive oil has been mixed with other substances either chemical or organic (e.g. other cheaper oils).

1. Determination of the composition and content of sterols.
Sterols are compounds which are normally found in oils and natural fats, in concentrations and compositions which vary depending on the origin of the fatty matter. Olive oil has quantities of around 1200 – 1800 mg/Kg (= sterol content). Vegetable oils contain roughly the same type of sterols but in different relationships and the characteristics for each are different (=sterol composition). This specificity should allow the mixture of olive oils with foreign oils to be recognized. In fact, the addition of appreciable quantities of foreign oil to an olive oil will alter its natural sterolic composition. This makes it possible to recognize fraud. However, the careful choice of foreign oils and the amount used may make it difficult to discover fraud. This analysis is carried out by means of gaschromatography.
 

2. Determination of erythrodiol and uvaol.
High values of these two substances may be an indication of the addition of residue oil to the olive oil. The solvent used for the extraction of residue oils (hexane) also dissolves these compounds, which are more abundant in the skins and kernels than in the pulp. However, the so-called “green” oils are high in erythrodiol and uvaol content, even though they have not been obtained through the use of solvents. This fact is due to the repressing of the pastes from the first pressing (“remilling”) and to the great pressure to which they are subjected or to new centrifugation. They have a deep green colour from which they get their name. This analysis is carried out through gaschromatography, usually contextually to sterols .

 3. Determination of saturated fatty acids in position 2 in the triglyceride.
This analysis allows us to have an indication of the presence of any esterified oils in pressed oils. The saturated fatty acids present in the molecule of the triglyceride of an olive oil are linked, for the greater part, to the glicerol in positions 1 and 3, while position 2 is preferably occupied by unsaturated fatty acids. This “uneven” distributioin in the three positions depends on the particular pathway of the biosynthesis of the triglycerides during the oiling of the fruit. On the other hand, the industrial process of chemical synthesis of the triglyceride (esterification) does not discriminate between saturated and unsaturated fatty acids (i.e., it “has no preferences”): this means that the quantity of saturates in position 2 will be greater than that present in a natural oil. This analysis determines this content by means of the use of enzymes (lipase) commonly in commerce.

4. Determination of the difference: ECN42 (HPLC) and ECN42 (theoretic calculation).
The aim of this determination is to ascertain the presence of seed oils added to olive oil. Since it is known the rule according to the fatty acids are distributed in the three positions of the triglyceride when this is formed due to biochemical synthesis in the olive fruit, it is possible to calculate the composition in triglycerides of the oil under examination by starting from the composition of its fatty acids. This calculation is easily made on a computer and with a suitable calculation programme. The composition in triglycerides must also be determined through analysis (by means of HPLC). A particular group of successive peaks, labelled ECN42, is compared for quantity with the corresponding value determined through calculation. In principle, the two values should be identical. In practice, however, there may be differences which must not exceed the legal limits. In fact, the presence of foreign oils, in particular of seed oil, increases this value greatly, thus revealing fraud.

5. Gaschromatographic analysis of methyl esters of fatty acids (and trans isomers).
The aim of this determination is to establish the percentage composition of fatty acids in olive oil, more commonly known as acidic composition. Since, as we know, fatty matters foreign to olive oil have acidic compositions which may be totally different, any mixture may be revealed by this means. In reality this analysis has nowadays lost a great deal of importance even though it was the first gaschromatographic determination carried out on olive oils. As we have seen, there are more efficient ways of reaching the same objectives. At present, EC Regulations give limits of concentration only for a few fatty acids which are considered “tracing”, that is, typical of oils other than olive. They are miristic (C14:0; coconut oil), linoleic (C18:3; linseed oil), arachidic (C20:0; peanut oil), eicosenoic (C20:1; rapeseed oil), beenic (C22:0; peanut oil), lignoceric (C24:0; peanut oil). EEC Regulation n. 1429/92 dated 26/5/92, L150, introduces limits for trans oleic isomer content and for trans linoleic and trans linolenic (commonly known as trans isomers). Illicit industrial procedures which tend to mask a seed oil in order to enable its use in mixtures with olive oil (e.g. de-sterolization, i.e. removal of sterols), cause some modifications in the structure of the fatty acids: in particular, they generate trans isomers. In olive oil, they are normally present in very low concentrations. Higher levels are an indication of unjustified industrial practices. The determination of trans isomer content is carried out contextually to the acidic composition, in particular analytic conditions.

6. Determination of the wax ester content through gaschromatography with capillary column.
The EEC Regulation n. 183/93 dated 29-1-93, L 22, introduces the determination of wax esteres and gives limits for their concentration. Wax esteres are compounds naturally present in olives (these are non gliceridal esters, that is they do not contain glicerol). In particular, they are more abundant on the epicarp of the drupe and, during pressing, some of them are transferred to the oil. The solvent used in the extraction of residue oil also dissolves a certain quantity of wax esteres which, after the removal of the solvent, are abundant in the oil. The aim of this determination is therefore to seek out mixtures of pressed olive oils and residue oils. As wax esters are compounds which contain, combined in the molecule, aliphatic alcohols (alkanols), the latter are present in much greater amounts in residue oils than in pressed oils. Before the introduction of this analysis, the law provided for the determination of the content of aliphatic alcohols. However, when the method was approved, it was already obsolete, since the means of reducing alkanol content was already known (and perhaps in use) (cold treatment in suitable solvents), thus nullifying the efficacy of the analysis.
Later, the possibility of performing the determination directly on the wax esters with 40,42,44 and 46 carbon atoms was studied. In fact, their content remains more or less constant even after the fraudulent treatments mentioned above.

7. Determination of the quantity of volatile halogenated solvents in olive oil
The presence of halogenated solvents (e.g. Freon, trichloroethylene, perchloroethylene, chloroform etc.), may derive either from the use of oils extracted with solvents or from environmental contamination. The presence of these compounds even in oils which are certainly pure has been the object of a great deal of research. It was discovered that in olive mills, the use of drinkable water for extractions by pressing, may cause the formation of halogenated compounds (especially chlorides and bromides) which are extremely soluble in oils, and which thus become more concentrated. Moreover, the contamination of the water strata caused by used industrial waters, in addition to the pollution of the atmosphere caused by halogenated solvents (one may think of the quantity of perchloroethylene used in dry-cleaning) which then penetrate the water strata in rainfall, are factors which influence greatly the levels of concentration of these compounds in oils. This analysis is carried out by gaschromatography.

In Conclusion...
Once again it must be emphasized that until now it has not been possible to reveal the presence of foreign oils by means of one single analysis. As to the different chemical analysis we must entrust ourselves to the authorities as most of us do not have access to such advanced instruments.
But a sensorial analysis by a practised olive oil taster will already take us a long way - and do trust your own taste as well. If there is any foreign taste to the oil, or if tastes mouldy, acidic, metallic or any other taste foreign to the olive, it is a good sign that the oil is either no only olive oil, or it is old, badly made, etc. A good oil tastes of olive, green or mature, with sometimes notes of nuttiness, grass, artichokes, apples, - and sometimes with either a bitter or a spicy aftertaste. If the perception of the defects overpowers the taste of the olive considerably, you should probably not consume the oil.

An important aspect: Health Benefits

The following is based on information has been provided by the IOOC.
Consumers have growing access to ever more comprehensive product information. Often this is supplied in publicity by the companies producing the product, in which case it is always subjective. Other times the sources are more objective, such as the media, reports by consumer organizations, and scientific or technical studies, although this last type of information takes longer to reach the general public. Consumers pay more attention to food products because the consequences they have can be beneficial or harmful to health.
Any information on olive oil would be incomplete if it did not take into account this important facet, especially when the beneficial effects of consuming olive oil are backed by lengthy, painstaking scientific research. The fat and oil sector is very complex. Fats and oils have a common denominator which is their energy value - 9 calories per gram - but the metabolism of each one or each group differs greatly from the rest. Olive oil contains a series of compounds that are very beneficial to most functions of the human body. Highly-qualified members of the scientific profession now discuss these on the basis of studies and experiments.
Olive oil's biological and therapeutic value is related in many aspects to its chemical structure. The first aspect is its triglyceride composition, made up of fatty acids. Olive oil has a prevalence (54 - 83%) of monounsaturated fat, oleic acid principally, while animal fats are fundamentally made up of saturated fatty acids and seed oils of polyunsaturated (50 - 72% in soybean and sunflower oil). Monounsaturated fatty acids are much more stable than polyunsaturated ones vis-à-vis the oxidative processes that, if produced, lead to rancidity. Olive oil also has a low percentage of polyunsaturated fats varying between 3.5 and 22.5%. These are essential fatty acids that cannot be synthesized by the body. However, a normal diet covers the essential fatty acid requirements of both adults and infants and has the best linoleic acid to linolenic acid ratio. Both olive oil and olive-pomace oil have an identical glyceridic structure, which means they share the same beneficial properties.
Secondly, olive oil's beneficial properties lie in its minor components. The most salient ones are the tocopherols, among them alpha-tocopherol which acts as vitamin E and carotene as provitamin A, and the polyphenols. All of these components have a major antioxidant function and are closely connected with virgin olive oils because refining processes alter and partially remove them in the other types.

Olive oil and the digestive system
According to Char bonnier, olive oil is the oil that is best tolerated by the stomach due to its high oleic acid content.
The tone of the sphincter which separates the stomach and esophagus and which impedes the reflux of gastric juices is less affected by olive oil. Butter is the least tolerated fat, while sunflower oil has intermediate effects. Gastric emptying time is affected in the same way by these three types of fat.
Since ancient times olive oil has been described as having a beneficial effect on hyperchlorohydric gastritis and gastroduodenaal ulcers, which is attributed to its protective function. When animal fats were replaced by olive oil in the diets of patients suffering from ulcers the result was a reduction of lesions in 33% of the cases and cicatrlzatlon in 55% (Taits). However, prescribing olive oil does not eliminate the need for drugs therapy.
Two tablespoons of olive oil taken in the morning on an empty stomach appear to have a positive effect on chronic constipation.
Olive oil has a very positive effect on atony of the gallbladder in that It has a more acute, gentle and prolonged action than prescribed drugs and other foods that have similar effects It inhibits hepatobiliary secretion during gallbladder emptying time and is therefore a pure cholagogue and can be used as a medicinal food. This effect has been known since ancient times and has been confirmed recently in numerous studies.
Cholelithiasis (gallstones) is a wide spread illness. It is related to the metabolism of fats and is found to a greater extent in more economically developed countries. Overall excess dietary intake, particularly of saturated fats and cholesterol, leads to increased biliary excretion of cholesterol and a reduction in bile acids and lecithin. It appears that high plasma cholesterol levels increase the risk of lithiasis because they simultaneously raise the fraction of cholesterol transported by the low-density lipoproteins (LDL) that inhibit the hepatic synthesis of cholesterol. It is also true, however, that the cholesterol transported by the high-density lipoproteins (HDL) is more easily metabolized into bile acids than it is excreted with bile, When a patient with a high cholesterol level undergoes treatment, plasma cholesterol has to be lowered by increasing its elimination via the biliary tract. For that reason, the majority of experts agree that foods rich in saturated and polyunsaturated fats play a possible role in the formation of calculi, while monounsaturated-rich olive oil would not appear to play such a role. Olive oil can be said to have a protective effect against the formation of gallstones, due to the way in which it activates bile flow and increases HDL, as well as to its balanced saturates: polyunsaturated ratio and its high content of monounsaturated. Messini and Cairella have demonstrated that there is a lower incidence of biliary calculi in areas of Italy where olive oil consumption is higher.

Olive oil in infancy
Fat intake is important to both the new-born baby and the weaned infant; even more important is the appropriate intake of essential fatty acids. Breast-fed babies receive 4 - 5% of their calories in the form of polyunsaturated acids, while babies fed on cow's milk receive substantially less. Low linoleic acid intake can delay growth and produce skin, hepatic and metabolic disorders. Seed oils, which are rich in polyunsaturates, are not recommended in large quantities for children because it is not advisable to lower their cholesterol level and because these oils promote peroxidative phenomena, especially in youngsters with low vitamin E reserves. Hence, it is important to strike a balance between the dietary supply of linoleic and linolenic acids because too much of the former can cause disorders of the nervous system. In his comparison of the effects of olive oil, sunflower oil and saturated fats on growing rats, Galli detected modifications in the structural lipids of the brain and liver among the groups treated with saturated fats and sunflower oil. There were none, however, in the group treated with olive oil. Olive oil provides a relatively low amount of essential fatty acids but has a balanced linoleic:linolenic ratio similar to that found in breast milk.
As regards the influence of olive oil on bone mineralization and development, a study by Laval-Jeantet demonstrates the need for fats. The most positive effects are obtained with the intake of oleic glycerides to which a minimum amount of polyunsaturates is added, and so the best diets for this purpose are those containing olive oil.

Olive oil and old age
From the very outset, food provides human beings with the energy necessary for the renewal and continuation of life. Each cell inherits a program that dictates its biological activity and that can be repeated an unlimited number of times. Successive repetition, however, produces errors that are corrected at first, but which over time become consolidated and give rise to incorrect information to which other errors are added. A diet rich in polyunsaturated fatty acids can lead to peroxidative phenomena, which expose cells to this production of errors. On the other hand, the presence of antioxidant substances, such as vitamin E, provides a defense mechanism. Mice fed on olive oil have a longer life expectancy than those fed on sunflower and corn oil. This is explained by the better ratio between vitamin E and polyunsaturated fatty acids in olive oil. When applied to man, this research makes for caution in the indiscriminate use of polyunsaturated-rich oils and leads to a preference for olive oil over other dietary fats because of its balanced content of linoleic acid, linolenic acid and anti-oxidant substances.
In a study on skin changes over time, Pinkey reported that people on a diet consisting of more than 10% polyunsaturates showed signs of aging. 60% of the cases had skin lesions removed that were suspected of being malignant.
Bone calcification is another problem common in the elderly. Olive oil seems to have a positive effect, which appears to be dose-dependent, because the more olive oil ingested the better the bone mineralization obtained. The explanation might lie in the large amount of oleates in the structural lipids of bones. According to French researchers, olive oil would appear to be necessary during growth and later in adulthood to avoid calcium loss.
Old age brings with it reduced digestive capacity and poor absorption of nutrients, especially of vitamins and mineral salts. Olive oil has the best characteristics as regards digestibility and absorption and has a mild laxative effect. Whether consumed cooked, fried, or better yet raw, in order to make the most of its vitamin and anti-oxidant content, olive oil helps make food more appetizing and aids digestion.

Olive oil and Arteriosclerosis and Cholesterol
Arteriosclerosis is one of the most widespread diseases in industrialized countries in which it is the leading cause of death. Together with genetic predisposition, there are other risk factors that cause the lesion to appear or become aggravated: smoking, arterial hypertension and hypercholesterolemia. Additional contributing factors are age, sex (male), diabetes, gout, a high triglyceride level, oral contraceptives and physical inactivity.
Cholesterol belongs to the sterol group and is a lipid that is abundant in animal tissue, insoluble in water and soluble in organic solvents. It forms part of cell membranes and in many cases constitutes a stable complex with phospholipids. In the body, cholesterol serves as the basis for the synthesis of other steroids involved in important processes such as the formation of bile acids that emulsify dietary fats so that they can be absorbed by the intestinal epithelium, or in the regulation of vitamin D.
The incidence of arteriosclerosis is closely linked to dietary habits. A diet rich in animal fats tends to raise plas-ma cholesterol. On the other hand, vegetable oils rich in polyunsaturated acids have an anti-atherogenic, protective action against cholesterol, and lower cholesterol levels.
As previously mentioned not all plasma cholesterol is atherogenic. The cholesterol transported by the low-density lipoproteins (LDL-cholesterol) is particularly so, whereas the cholesterol carried by the high-density lipoproteins (HDL-cholesterol) appears to have a protective effect since their function is to eliminate free cholesterol in the cells and to esterify and carry it to the liver where it is emptied with the bile.
Numerous studies have confirmed a negative correlation between plasma HDL levels and arteriosclerosis and a positive correlation between HDL and a longer life expectancy.
Any treatment of hypercholesterolemia must begin by lowering saturated fat intake. The suppression of these fats produces a reduction in plasma cholesterol double that obtained through the addition of an equal amount of polyunsaturated-rich lipids (Keys, Grande Covian et al.). If the substitution is with olive oil, which is rich in monounsaturates, the total cholesterol level is approximately equal to that obtained through the reduction of saturated fat intake. The positive effect of monounsaturated fats is not limited to a similar substitution effect as for polyunsaturated fats. It also increases HDL cholesterol and helps protect against coronary mortality. A comparative study of deaths from coronary disease in 10,000 men has indicated that at the same plasma cholesterol levels, the risk of developing this type of disease was approximately the same in American and Finnish men, while it was much lower in Mediterranean men who consumed a high percentage of olive oil among other fats.
When eaten in excess, polyunsaturate-rich vegetable oils peroxidize easily and for that reason can become atherogenic. This is a possible cause of endothelial lesions and platelet hyperaggregation.
A fitting conclusion to this chapter is to point out that the most important step in the prevention of arteriosclerosis is to lower animal fats - visible and invisible - and to replace them by monounsaturated-rich olive oil, which also contains a balanced amount of polyunsaturated adequately protected by anti-oxidants like alpha-tocopherol or polyphenols. This dietary approach, which has been confirmed by experimental and epidemiological research, will permit rational disease prevention and satisfactory control of plasma cholesterol, without the risk of undesirable side effects.

Olive oil and frying
To make food more appetizing, man uses cooking methods like boiling, baking, smoking and frying, with the highest temperatures being reached during frying.
The temperature inside fried food remains almost constant at 100 degrees C until its water content evaporates. At that point the hot oil can penetrate. The food cooks quickly and the loss of nutritional value is lesser than with other cooking methods, according to studies by Varela. A crust forms on the outside as a result of the reaction with the hot oil, which coagulates proteins and caramelizes the glycides. Less fat is consumed than with other cooking methods, as the oil is not absorbed by the food.
Fats are subjected to auto-oxidative phenomena that are accelerated as temperatures rise. These phenomena are heightened by the degree of un-saturation of the fat and the presence of pro-oxidant substances, while they are checked by antioxidants. Some of the products of deterioration formed are volatile and easily eliminated; others (polymers) are poorly absorbed and some of those that remain can be toxic and can affect different organs and detract from the nutritive value of the food.
Animal fats, which have a low degree of un-saturation, do not contain antioxidants and soon undergo auto-oxidation. Seed oils are highly unsaturated and oxidize rapidly. On the contrary, olive oil is very stable because of its intermediate degree of un-saturation and the anti-oxidants if contains. Besides being affected by the type of fat, deterioration is related to the temperature reached, heating time, type of food involved, and the presence of catalysts.
Fedeli has demonstrated the stability of olive oil at high frying temperatures, and Varela has proven that food digestibility is not modified by frying in olive oil, not even when the same oil was used 10 times over to fry meat and sardines. This research would appear to indicate that olive oil is the oil best suited to frying owing to its higher resistance to oxidative deterioration.
To sum up this entire chapter, we can conclude that owing to its fatty acid structure, Its content in vitamin E and other anti-oxidants, its balanced contents of other components, and its aroma and flavor, olive oil is the oil that is best suited to human consumption -whether raw or cooked - and has a protective effect on human health.