Health Benefits of Extra Virgin Olive Oil

Extra virgin olive oil is distinguished from all other oils (even other grades of olive oil) in that it is richly endowed with a unique combination of monounsaturated fats, polyphenols and phytosterols. A consistent body of scientific evidence exists that diets rich in these three natural components are associated with:

• Lower levels of “bad cholesterol” (LDL) and higher levels of “good cholesterol” (HDL).
• Lower levels of heart-unfriendly oxidized LDL’s.
• Reduced DNA oxidative damage which in turn is related to a reduced risk of some cancers.
• Reduced incidence of hypertension.
• Improved glycemic control, which is particularly advantageous to diabetic patients.

The quality of olive oil production - especially the stage of pressing - really does make a difference when it comes to health benefits. Recent studies have compared the anti-inflammatory benefits of extra virgin olive oil (EVOO) obtained from the first pressing of the oil to the anti-inflammatory benefits of virgin olive oils (non-EVOO) obtained from later pressings.

A reduction in inflammation markers was identified by researchers that EVOO  lowered the inflammatory markers in the blood when non-EVOOs were unable to do so. (Study measurements included blood levels of thromboxane A2, or TXA2, and leukotriene B2, or LBT2.)

This ability of extra virgin olive oil to help protect against unwanted inflammation is not surprising, since EVOO is known to contain stronger concentrations of phytonutrients (especially polyphenols) that have well-known anti-inflammatory properties. 


The anti-inflammatory strength of olive oil rests on its polyphenols. These anti-inflammatory compounds include at least nine different categories of polyphenols and more than two dozen well-researched anti-inflammatory nutrients, including the following: Anthocyanidins (cyanidins,  peonidins); Flavones (apigenin, luteolin); Flavonols (quercetin; kaempferol); Flavonoid glycosides (rutin);  Lignans (pinoresinol); Hydroxycinnamic acids ( caffeic acid, cinnamic acid,  ferulic acid, coumaric acid); Hydroxybenzoic acids (vanillic acid, syringic acid);  Tyrosols (oleuropein, tyrosol,  hydroxytyrosol, ligstroside).

Research has documented a wide variety of anti-inflammatory mechanisms used by olive oil polyphenols to lower our risk of inflammatory problems. These mechanisms include decreased production of messaging molecules that would otherwise increase inflammation (including TNF-alpha, interleukin 1-beta, thromboxane B2, and leukotriene B4); inhibition of pro-inflammatory enzymes like cyclo-oxygenase 1 and cyclo-oxygenase 2; and decreased synthesis of the enzyme inducible nitric oxide synthase.

In heart patients, olive oil and its polyphenols have also been determined to lower blood levels of C-reactive protein (CRP), a widely used blood measurement for assessing the likelihood of unwanted inflammation. They have also been found to reduce activity in a metabolic pathway called the arachidonic acid pathway, which is central for mobilizing inflammatory processes.

These anti-inflammatory benefits of extra virgin olive oil do not depend on large levels of intake. As little as 1-2 tablespoons of extra virgin olive oil per day have been shown to be associated with significant anti-inflammatory benefits.

Heart disease reduction has been identified in numerous studies of the Mediterranean Diet that olive oil intake contributed to a decreased risk of heart disease. However, a recent group of studies has provided us with a fascinating explanation of olive oil's cardioprotective effect. One of the key polyphenols in olive oil - hydroxytyrosol (HT) - helps protect the cells that line our blood vessels from being damaged by overly reactive oxygen molecules.

HT helps protect the blood vessel cells by triggering changes at a genetic level. The genetic changes triggered by HT help the blood vessel cells to enhance their antioxidant defense system. In other words, olive oil supports our blood vessels not only by providing antioxidants like like vitamin E and beta-carotene. Olive oil also provides our blood vessels with unique molecules like HT that actually work at a genetic level to help the cellular walls of the blood vessels remain strong.

Olive oil has long been recognized for its unusual fat content. This plant oil is one of the few widely used culinary oils that contains about 75% of its fat in the form of oleic acid (a monounsaturated, omega-9 fatty acid).

In terms of monounsaturated fat, the closest common culinary oil to olive is canola oil, with about 60% of its fat coming in monounsaturated form. By contrast, the fat in soybean oil in only 50-55% monounsaturated; in corn oil, it's about 60%; in sunflower oil, about 20%; and in safflower oil, only 15%.

When diets low in monounsaturated fat are altered to increase the monounsaturated fat content (by replacing other oils with olive oil), research study participants tend to experience a significant decrease in their total blood cholesterol, LDL cholesterol, and LDL:HDL ratio.

Recent research studies have taken these heart-healthy effects of olive oil one step further. Olive oil's monounsaturated fat content (specifically, its high level of oleic acid) has now been determined to be a mechanism linking olive oil intake to decreased blood pressure. Researchers believe that the plentiful amount of oleic acid in olive oil gets absorbed into the body, finds its way into cell membranes, changes signaling patterns at a cell membrane level (specifically, altering G-protein associated cascades) and thereby lowers blood pressure.

To our knowledge, this is the first time that the monounsaturated fat content of olive oil has been linked not only to cholesterol reduction, but also to reduction of blood pressure.

Anti-clotting benefits have been demonstrated by various laboratory studies have also found that 2-(3,4-di-hydroxyphenyl)-ethanol (DHPE), a phenol component of extra-virgin olive oil with potent antioxidant properties, is able to inhibit platelet aggregation (blood clotting) more effectively that other flavonoids. The phenol enriched portion of olive oil also demonstrated similar activity. 
 

This is important because heart attacks and strokes are caused by blood clots which build up in the arteries of the heart or brain which have been narrowed due to atherosclerotic plaque formation. The ability to form normal blood clots to physical trauma is of course necessary to prevent hemorrhage (uncontrolled bleeding), however the degree of blood clot inhibition which would occur due to olive oil consumption would not be so severe that it would be dangerous at all.

Cancer prevention has been one of the most active areas of olive oil research, and the jury is no longer out on the health benefits of olive oil with respect to cancer. Twenty-five studies on olive oil intake and cancer risk - including most of the large-scale human studies conducted up through the year 2010 - have recently been analyzed by a team of researchers at the Mario Negri Institute for Pharmacological Research Institute in Milan, Italy.

Firmly established by this research team were the risk-reducing effects of olive oil intake with respect to cancers of the breast, respiratory tract, upper digestive tract and, to a lesser extent, lower digestive tract (colorectal cancers). These anti-cancer benefits of olive oil became most evident when the diets of routine olive oil users were compared with the diets of individuals who seldom used olive oil and instead consumed diets high in saturated added fat, especially butter.

There is also encouraging research on the potential for olive oil to help with control of certain cancers once they have already developed. For example, improvement of breast cancer status has been an area of particular interest in olive oil research. Here some of the research has focused on the secoiridoids in olive oil (especially oleocanthal), and its ability to help keep breast cancer cells from reproducing.

Another example involves the ability of hydroxytyrosol (HT) in olive oil to trigger programmed cell death (apoptosis) in colon cancer cells. HT may be able to accomplish this anti-cancer effect by helping block the enzymatic activity of fatty acid synthetase (FAS). These cancer-controlling properties of olive oil and olive oil constituents are generally referred to as the "antiproliferative" properties of olive oil. We expect to see more future research in this area.

Digestive health benefits of olive oil for the digestive tract were first uncovered in research on diet and cancers of the digestive tract. Numerous studies found lower rates of digestive tract cancers - especially cancers of the upper digestive tract, including the stomach and small intestine - in populations that regularly consumed olive oil.

Recent research has provided us with even more information, however, about olive oil, its polyphenols, and protection of the digestive tract. One fascinating area of recent research has involved the polyphenols in olive oil and the balance of bacteria in our digestive tract. Numerous polyphenols in olive oil have been shown to slow the growth of unwanted bacteria, including bacteria commonly responsible for digestive tract infections.

These polyphenols include oleuropein, hydroxytyrosol, and tyrosol. Some of these same polyphenols - along with other olive oil polyphenols like ligstroside - are specifically able to inhibit the growth of the Helicobacter pylori bacterium. This effect of the olive oil polyphenols may be especially important, since overpopulation of Helicobacter bacteria coupled with over-attachment of Helicobacter to the stomach lining can lead to stomach ulcer and other unwanted digestive problems.

Improved cognitive function - especially among older adults - is a well-known feature of the Mediterranean Diet. As the staple oil in that diet, olive oil has been of special interest for researchers interested in diet and cognitive function. In France, a recent study large-scale study on older adults has shown that visual memory and verbal fluency can be improved with what the researchers called "intensive use" of olive oil. In this case, "intensive use" meant regular use of olive oil not just for cooking, or as an ingredient in sauces and dressings, but in all of these circumstances.

Note: Be aware that heat, light and air can affect the taste of olive oil and its health-promoting nutrients. Always store olive oil in a dark, room-temperature cupboard. Also, the flavor and nutrients of extra virgin olive oil slowly degrade over time, so it is best used within two years of harvest and within a few months of opening.

Note: Suggested consumption is 2-3 daily tablespoons of high quality extra virgin olive oil, preferably in place of other fats.

Reference: Death to Diabetes Website