Cretan Diet II: Olive Oil

As it was underlined in the previous post, the olive oil is the basic constituent of the Cretan diet. A diet that is highlighted by the long live of the cretan people and their good health. Although these to two facts seem to be somewhat unrelated, since one is a fat and the other is health, the truth is (and it is backed up by scientific evidence) that they shed some light to the “mystery”. We will see why olive oil is so good for you, but we will also see that olive oil from olive oil is very different, not only by the name they go by, but for the health benefits.
Before we continue, let’s see first what an oil molecule is and how it is made. The foundation of all oils are the fatty acids. Fatty acids, and as all organic molecule consists of primarily Carbon and Hydrogen atoms.They are long chains of hydrocarbons terminating in a -COOH which is just an acid. One is shown in the picture below (a). To simplify the image we will do some assumptions that all chemist do (b). Carbon atoms are not shown but they will be assumed to be in either side of each line. The line will represents the bonds between the two items. The hydrogens are omitted because they don ‘t have any importance and they complicate the pictorial, but you can imagine that there are two in each carbon atom.

GBCFUYQ43T58743TBRW

The major elements here are the length of the chains and the bond type. The first item basically determines the size of the molecule. The second item is more important and determines the shape of the molecule. Occasionally there is a double bond meaning that one carbon atom is attached to the next one with two bonds. That means not only two less hydrogens, but also that creates a kink in the molecule bending it as shown in the picture. This is called monounsaturated fat. If there are more than one double bond are polyunsaturated.

wetgeqrtgcercfeadfgwecr

This changes many things in the properties of the molecule. As you can imagine straight molecules can be packed much more efficiently compared to the kinked molecules. More packed molecules are closer together making the macroscopic properties more like a solid even at slightly elevated temperatures. The kinked molecule on the other hand are packed less cohesively making them more like liquid rather than solid in a wide range of temperature. Some studies have shown that these kinds of fats can actually lower LDL (bad) cholesterol and maintain HDL (good) cholesterol. One drawback with unsaturated fats, is that the double bond is very easily broken and there are atoms that can take its place. This results in rancidity of the fats, and that’s why the food industry does not prefer them over the saturated. One more notable effect, is the effect they have on cell membranes. Lipids like these, can come and be adsorbed on the cell membrane interstitially. Due to the high volume they occupy they are pushing apart the bi-lipids that consist the membrane making them more elastic. This is especially good for the arteries since the elasticity reduces the risk of heart disease. It is theorized that, in the long term, increased elasticity of arterial walls reduces vascular stress and consequentially the risk of two common causes of death—heart attacks and stroke.

wjreytgwebrwe

Since we are on the topic we should mention about the omega-3 fatty acids that are monosaturated fatty acids, with the double bond at a very specific location. Omega denotes the endo of the chain, while the 3 denotes the location of the bond. So omega-3 means third from the end as in the picture below. These include an “essential” fatty acid, which means it’s critical for our health but cannot be manufactured by our bodies. Good sources of omega-3 fatty acids include cold-water fish, flax seed, soy, and walnuts. These fatty acids may reduce the risk of coronary heart disease and also boost our immune systems. Similar is the concept for the omega-6 and omega-9 fatty acids, that are however not so good for the heart.

EAFDSQEWFXwwaxdwS

 And type fro the big truth, the actual fats do not look like that. Yes… I kinda lied. Well these molecules are fatty acids, and they are the fats, but they are nasty tasting and very foul smelling. These are not what we eat. As I said these are the building blocks that fats are made of. One fat is actually made from a triglyceride which is a glycerol molecule with three fatty acids attached to it. The fundamentals of the properties, we discussed above, are still in effect and the significance of the double bond is the same. A molecule that consists of oleic acids, the major fatty acid of the olive oil, looks like this:

safasfwETGERDSAVSDFVDS
And ow you know why I did not drew this since the beginning. Evidence from epidemiological studies suggests that a higher proportion of monounsaturated fats in the diet is linked with a reduction in the risk of coronary heart disease. Although the link is not yet understood it is something that has been confirmed numerous times with several unsaturated oils, predominately however, with olive oil. This is significant because olive oil is considerably rich in monounsaturated fats, most notably oleic acid. the Cretan diet has achieved this benefit, by using olive oil to replace a similar amount of saturated fat like butter, and animal rendered fat. There is a large body of clinical data to show that consumption of olive oil can provide heart health benefits such as favorable effects on cholesterol regulation and LDL cholesterol oxidation, and that it exerts antiinflamatory, antithrombotic, antihypertensive as well as vasodilatory effects both in animals and in humans. As they are the least processed forms of olive oil, extra virgin or virgin olive oil have more monounsaturated fatty acids than other olive oil. These types also contain more polyphenols, which may have benefits for the heart. 

Some clinical evidence suggests that it is olive oil’s phenolic content, rather than its fatty acid profile, that is responsible for at least some of its cardioprotective benefits. For example, a clinical trial published in 2005 compared the effects of different types of olive oil on arterial elasticity. Test subjects were given a serving of 60 g of white bread and 40 ml of olive oil each morning for two consecutive days. he study was conducted in two stages. During the first stage, the subjects received polyphenol-rich oil (extra virgin oil contains the highest amount of polyphenol antioxidants). During the second phase, they received oil with only one fifth the phenolic content. It was discovered that after the subjects had consumed olive oil high in polyphenol antioxidants, they exhibited increased arterial elasticity, while after the consumption of olive oil containing fewer polyphenols, they displayed no significant change in arterial elasticity.

To conclude I will refer to the observation that was made by the Rockafeler institute. In 1947 members of the Rockefeller Institute came to Crete in order to assess the health of the population after the war. They concluded that the level of their physical health was very good indeed. Cretans were 90% healthier than the American population. Even though the medical world needed a long time to comprehend the consequences of these discoveries, the basics of the Cretan diet have become a question for debate. Ten years later a study of seven countries, devised and directed by Dr. Ansel Keys, special cardiologist from Minnesota State, made Crete famous. He studied the health of people from 7 different countries; Holland, Finland, Japan, USA and of Mediterranean countries Italy, Yugoslavia and Greece. From Greece he studied Cretans and inhabitants of Corfu. From all the population groups studied, the groups of Italy and Yugoslavia presented lower mortality from cardiovascular diseases compared with the groups of North Europe and USA. However what astonished them were the results of Cretans; they presented the lowest rate of mortality, independently from the cause of death. The Research was continued in 1991. The Sector of Social Medicine of the University of Crete undertook the review of individuals that had taken part in the research 31 years previously, and found that the survival rate of the Cretan group was 50%, while in Finland there were no survivors.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s