Thanks to its status as a spotlight food in the Mediterranean Diet, and thanks to extensive research on its unique phytonutrient composition, olive oil has become a legendary culinary oil with very difficult-to-match health benefits. Among its extensive list of phytonutrients, no single category of nutrients is more important than its polyphenols. The polyphenol content of this delicious oil is truly amazing! The list below shows some of the key polyphenols found in olive oil, organized by their chemical category:

 

	Simple Phenols	Anthocyanidins
	• tyrosol	• cyanidins
	• hydroxytyrosol	• peonidins
	Terpenes	Flavonols
	• oleuropein	• quercetin
	• ligstroside	• kaempferol
	Flavones	Flavonoid Glycosides
	• apigenin	• rutin
	• luteolin	Lignans
	Hydroxycinnamic acids	• pinoresinol
	• caffeic acid	Hydroxybenzoic Acids
	• cinnamic acid	• vanillic acid
	• ferulic acid	• syringic acid
	• coumaric acid

Most of the polyphenols in this list have been shown to function both as antioxidants and also as anti-inflammatory nutrients in the body. The very number and variety of polyphenols in olive oil helps explain the unique health benefits of this culinary oil.

Anti-Inflammatory Benefits

It’s unusual to think about a culinary oil as an anti-inflammatory food. Plant oils are nearly 100% fat, and in a general dietary sense, they are typically classified as “added fats.” Intake of too much added dietary fat can be a problem for many reasons— including reasons involving unwanted inflammation. So it’s pretty remarkable to find a culinary oil that’s repeatedly been shown to have anti-inflammatory properties and provide health benefits in the area of unwanted inflammation. Yet that’s exactly the research track record that describes extra virgin olive oil.

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. 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.

Cardiovascular Benefits

Many different cardiovascular problems—including gradual blocking of the arteries and blood vessels (called atherosclerosis)—have their origin in two unwanted circumstances. The first of these circumstances is called oxidative stress. Oxidative stress means too much damage (or risk of damage) from the presence of overly reactive oxygen-containing molecules. One of the best ways to help avoid oxidative stress is to consume a diet that is rich in antioxidant nutrients. The second of these circumstances is ongoing (chronic) and undesirable low-level inflammation. Undesirable and chronic inflammation can result from a variety of factors, including unbalanced metabolism, unbalanced lifestyle, unwanted exposure to environmental contaminants, and other factors. One of the best ways to help avoid chronic and unwanted inflammation is to consume a diet that is rich in anti-inflammatory nutrients. Any food that is rich in antioxidant and anti-inflammatory nutrients is a natural candidate for lowering our risk of heart problems, because it contains the exactly right combination of nutrients to lower our risk of oxidative stress and chronic, unwanted inflammation. Many foods contain valuable amounts of antioxidants and anti-inflammatory compounds, but few foods are as rich in these compounds as extra virgin olive oil, and this fact alone accounts for many of the research-based benefits of this culinary oil for health of our cardiovascular system.

In terms of antioxidant protection for our blood vessels, olive oil has been shown to lower risk of lipid peroxidation (oxygen damage to fat) in our bloodstream. Many of the fat-containing molecules in our blood—including molecules like LDL—need to be protected from oxygen damage. Oxygen damage to molecules like LDL significantly increases our risk of numerous cardiovascular diseases, including atherosclerosis. Protection of the LDL molecules in our blood from oxygen damage is a major benefit provided by olive oil and its polyphenols. Equally important is protection against oxygen damage to the cells that line our blood vessels. Once again, it’s the polyphenols in olive oil that have been shown to provide us with that protection.

One process we don’t want to see in our blood vessels is too much clumping together of blood cells called platelets. While we want to see blood platelets clump together under circumstances like an open wound, where their clumping together acts to seal off the wound, we don’t want this process to occur in an ongoing way when there is no acute emergency. Several of the polyphenols found in olive oil—including hydroxytyrosol, oleuropein and luteolin—appear to be especially helpful in keeping our blood platelets in check and avoiding problems of too much clumping (called platelet aggregation). There are also two messaging molecules (called plasminogen activator inhibitor-1 and factor VII) that are capable of triggering too much clumping together of the platelets, and the polyphenols in olive oil can help stop overproduction of these molecules.

Olive 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). Research has long been clear about the benefits of oleic acid for proper balance of total cholesterol, LDL cholesterol, and HDL cholesterol in the body. When diets low in monounsaturated are made high in monounsaturated fat (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. Those are exactly the results we want for heart health. In addition to these cholesterol-balancing effects of olive oil and its high oleic acid content, however, comes a new twist: recent research studies have shown that olive oil and its oleic acid may be important factors for lowering 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.

Interestingly, a recent laboratory animal study adds one note of caution for anyone wanting to bring the unique cardiovascular benefits of olive oil into their diet. This study found that cardiovascular benefits from olive oil and its polyphenols were not realized when the laboratory animals consumed too many calories and too much total food. This result suggests that olive oil—outstanding as it is in polyphenol protection of our cardiovascular system—needs to be integrated into an overall healthy diet in order to provide its expected benefits.

Digestive Health Benefits

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. Studies on the Mediterranean Diet were an important part of this initial research on olive oil and the digestive tract. Protection of the lower digestive tract (for example, protection of the colon from colon cancer) is less well-documented in the olive oil research, even though there is some strongly supportive evidence from select laboratory animal studies. Many of these anti-cancer effects in the digestive tract were believed to depend on the polyphenols in olive oil and their antioxidant plus anti-inflammatory properties. One particular category of polyphenols, called secoiridoids, continues to be a focus in research on prevention of digestive tract cancers.

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.

Bone Health Benefits

Support of overall bone health is another promising area of olive oil research. While most of the initial study in this area has been conducted on laboratory animals, better blood levels of calcium have been repeatedly associated with olive oil intake. In addition, at least two polyphenols in olive oil—tyrosol and hydroxytyrosol—have been shown to increase bone formation in rats. A recent group of researchers has also suggested that olive oil may eventually prove to have special bone benefits for post-menopausal women, since they found improved blood markers of overall bone health in female rats who had been fed olive oil after having their ovaries removed. Taken as a group, the above studies suggest that bone health benefits may eventually be viewed as an important aspect of olive oil intake.

Cognitive Benefits

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.

Equally fascinating to us in the area of cognition has been recent research on olive oil intake and brain function. In laboratory animals with brain function that had been compromised by lack of oxygen, consumption of olive oil helped offset many different types of brain-related problems, including unbalanced water content, unbalanced nervous system activity, and too easy passage of molecules across the blood brain barrier. This animal research has given scientists many further clues about the ways in which olive oil might provide us with cognitive benefits. The ability to help protect our brain during times of imbalance may turn out to be one of the special health benefits offered by this unique culinary oil.

Anti-Cancer Benefits

The polyphenols found in olive oil are a natural for helping us lower our risk of certain cancer types. Many types of cancer only get initiated when cells are overwhelmed by oxidative stress (damage to cell structure and function by overly reactive oxygen-containing molecules) and by chronic excessive inflammation. Since the polyphenols in olive oil act both as antioxidants and anti-inflammatory molecules, they are perfectly suited for lowering our cells’ risk of oxidative stress and chronic unwanted inflammation. Research studies have shown that as little as 1-2 tablespoons of olive oil per day can lower our risk of certain cancer types, including cancers of the breast, respiratory tract, upper digestive tract, and to a lesser extent, lower digestive tract (colorectal cancers). In some research studies, the anti-cancer benefits of olive oil do not show up until the diets of routine olive oil users are compared with the diets of individuals who seldom use olive oil and who instead consume added fats that are more saturated in composition (for example, butter).

While most of the anti-cancer research on olive oil has focused on its polyphenols and their antioxidant and anti-inflammatory properties, several studies have uncovered other fascinating ways in which olive oil provides its anti-cancer benefits. These other ways include the improvement of cell membrane function in a way that lowers risk of cancer development and the altering gene expression in cells in a way that enhances their antioxidant defense system. A final important mechanism linking olive oil intake to decreased cancer risk involves protection of our DNA. The antioxidants in olive oil appear to have a special ability to protect DNA (deoxyribonucleic acids)— the key chemical component of genetic material in our cells— from oxygen damage. DNA protection from unwanted oxidative stress means better cell function in wide variety of ways and provides a cell with decreased risk of cancer development.

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.