Anyone coming from the Mediterranean region of the world would tell you about the health benefits, as well as the wonderful flavor, of a good dose of olive oil on salads, pasta, fish and almost anything else. Fortunately, it is available throughout the year to satisfy taste buds and promote good health.
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.
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:
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.
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.
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.
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.
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.
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.
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.
Olive oil is made from the crushing and then subsequent pressing of olives. The fact that olives are rich in oil is reflected in the botanical name of the olive tree—Olea europea—since the word "oleum" means oil in Latin. Olive oil is available in a variety of grades, which reflect the degree to which it has been processed. Extra virgin olive oil is derived from the first pressing of the olives and has the most delicate flavor and strongest overall health benefits. See How to Select and Store for more information on these different grades of olive oil.
Olives, one of the oldest foods known, are thought to have originated in Crete or Syria between five and seven thousand years ago. Since ancient times, the olive tree has provided food, fuel, timber and medicine for many civilizations, and has been regarded as a symbol of peace and wisdom. The venerable oil of the olive has been consumed since as early as 3,000 B.C.
It's not clear exactly how olive trees arrived in the U.S., but it's clear that the time frame was much later, during the 1500-1700's. Spanish colonizers of North America definitely brought olive trees across the Atlantic Ocean during the 1500-1700's, and while some may have been brought directly to the region which is now California, olive trees may also have been brought to the region from Mexico, where cultivation by the Spanish was already underway.
Olive oil has been and still is a staple in the diet of many Mediterranean countries. The recent discovery that the Mediterranean diet, which features this prized oil, may be linked to a reduced risk of heart disease and other health conditions has caused olive oil to become very popular in the United States in the past few decades. Today, much of the commercial cultivation of olive oil is still centered in the Mediterranean region in such countries as Spain (36% of total production), Italy (25%), and Greece (18%). These countries—along with the remaining European countries—also consume about two-thirds of all olive oil that is produced. Regions of the world with quickly-increasing consumption and production of olive oil include South America (especially Chile) and Australia.
Since olive oil can become rancid from exposure to light and heat, there are some important purchasing criteria you should follow to ensure buying a better quality product. Look for olive oils that are sold in dark tinted bottles since the packaging will help protect the oil from oxidation caused by exposure to light. In addition, make sure the oil is displayed in a cool area, away from any direct or indirect contact with heat.
When you shop for olive oil, you will notice a host of different grades are available, including extra-virgin, virgin, refined and pure:
It is important to note, however, that acidity is by no means the only difference between EVOO and other grades of olive oil. In fact, a sizeable amount of controversy has arisen within the olive oil industry over key characteristics of EVOO and the extent to which these characteristics are present in commercial products. Since over 90% of all EVOO consumed in the United States is imported, many evaluators of EVOO have looked to the International Olive Council (IOC) headquartered in Madrid, Spain for quality criteria in evaluating EVOO. However, unlike Italy, Spain, Greece, Portugal, and other European Union countries that were founding members of the IOC, the United States has never become an official IOC member country or adopted IOC standards for EVOO as its own mandatory standards.
In the United States, voluntary standards for olive oil have traditionally been set by the U.S. Department of Agriculture (USDA), which in 2010 did update its own standards to more closely resemble IOC standards in terms of EVOO chemistry. However, even though most IOC chemical standards like percent free acidity were adopted by the USDA, some differences remain between IOC and USDA chemical criteria. (In addition, since 2010, the IOC has gone on to update and revise some of its chemical standards, and these changes are not reflected in the existing USDA criteria.) But a perhaps even bigger part of the controversy over EVOO standards has not involved chemical criteria like percent free acidity but rather sensory criteria (also called "organoleptic" criteria) like taste and aroma. If you consider olive oil as falling into the category of a fresh fruit juice (in the sense that an olives actually belong to a special group of fruits called "drupes" and can be pressed to obtain their oil or "juice"), aroma and taste might be considered as defining characteristics of this food. Assurance of excellent taste and aroma is a more difficult regulatory standard than assurance of a chemical standard like percent free acidity, and to some extent may require closer monitoring of local conditions and plant varieties. In this context, several organizations in the U.S. offer their own quality seal for EVOO, including the California Olive Oil Council (COOC) and the North American Olive Oil Association (NAOOA). Quality seals from these organizations can help provide assurance about EVOO quality.
Similar organizations exist in Europe and can be helpful for assuring EVOO quality. In most cases, your best bet is to look for specific initials on the olive oil container that represent official review and sanctioning by these organizations. Among your options here are the designations "A.O.C." or "D.O.P." or "D.P.O." or "D.O." "A.O.C." stands for the French term "Appellation D'origine Controlée." "D.O.P." stands for the Italian "Denominazione d'Origine Protetta" (note that D.O.P. is also written as "D.P.O." in some other European countries). In Spain, a similar designation is "D.O." which stands for "Denominacion de Origen." Any of these initials can help provide assurance of quality with respect to extra virgin olive oils.
Another term that you may see on a bottle of olive oil is "cold pressed." This term means that very minimal heating (and by IOC standards, under 81F/27C) was used when mechanically processing the olives to obtain their oil. We like the idea of cold pressed extra virgin olive oil, because we believe that minimal use of heating, combined with the phytonutrient-rich first pressing of the oil, provides the strongest possible nutrient composition from an extracted oil.
Proper storage techniques for olive oil are very important, not only to preserve the delicate taste of the oil, but also to ensure that it does not spoil and become rancid, which will have a negative effect on its nutritional profile.
Even though olive oil's monounsaturated fats are more stable and heat-resistant than the polyunsaturated fats that predominate in other oils (especially the easily damaged omega-3 fatty acids found in flax seed oil, which should always be refrigerated and never heated), olive oil should be stored properly and used within 1-2 months to ensure its healthy phytonutrients remain intact and available. Research studies have shown compromise in the nutritional quality of olive oil after two months' period of time, even when the oil was properly stored.
Proper storage of olive oil includes protection from light. There is debate about the ideal type of storage container. Tinted glass bottles are one of the best storage options for preventing unwanted contamination of the olive oil with packaging materials (as might occur, for example, with the use of dark plastic bottles in which very small amounts of plastic might migrate from the bottle into the oil). However, depending upon the degree and type of glass tinting, exposure to all light might not be prevented with the use of tinted glass. Metal containers for olive oil storage are also an option, although it is unclear about the potential for olive oil to be affected by the metal elements in the container. The transfer of olive oil to a sealed ceramic container is also an option. If you decide to purchase olive oil in a tinted glass bottle, we recommend that you store it in a lightproof area, like a cabinet with solid doors or closed pantry. If you decide to purchase in either plastic or metal containers, you may want to take the additional step of moving the oil into a ceramic container that can be sealed. If you aren't sure how quickly you will be using your olive oil, you may want to buy it in small-size amounts to avoid the problems that can arise with longer-term storage.
Purchase only as much as you will use in one to two months and store away from light and heat. Protect your olive oil's flavor and antioxidants by transferring 7 to 10 days' worth of oil to a smaller bottle to lessen the oxidation that occurs when the oil is exposed to air. Leave this small bottle at room temperature for easy use, but refrigerate the rest. When chilled, olive oil will solidify slightly and turn cloudy, but once restored to room temperature, it will regain its normal appearance, and its quality will be better maintained. Although it may be convenient, definitely don't store your olive oil near the stove as the heat will damage it.
While we haven't seen research that discusses declines in carotenoids and vitamin E for extra virgin olive oil, we have seen it for virgin oil. While this is not the type of oil we recommend, we still thought to include this interesting information here:
Research conducted at the University of Lleida in Spain and reported in the Journal of Agriculture and Food Chemistry found that levels of chlorophyll, carotenoids and antioxidant phenols dropped dramatically after virgin olive oil had been in storage 12 months-even under the best controlled conditions.
Chlorophyll content dropped by as much as 30%; beta-carotene by 40%, and vitamin E (alpha-tocopherol) by 100%!
Phenols, which are not only the main antioxidants in virgin olive oil, but are also responsible for its distinctive rich flavor, also dropped precipitously after 12 months storage.
Research published in New Scientist magazine has confirmed that light destroys many of the antioxidants in olive oil. Researchers at the University of Bari, in southern Italy, compared oils stored in the light or in the dark for 12 months. Oils stored in clear bottles under supermarket lighting lost at least 30% of their tocopherols (vitamin E) and carotenoids.
After just two months' exposure to light, peroxide (free radical) levels had increased so much that the olive oil could no longer be classified as extra virgin.
You'll find that many of our recipes feature extra virgin olive oil. For example, we like to add it to vegetables after they have been lightly cooked, either on its own, or as part of our Mediterranean Dressing.
Olive oil is not a commonly allergenic food and is not known to contain measurable amounts of oxalates.
|
Olive Oil, cold pressed extra virgin
1.00 TBS 13.50 grams
Calories: 119
GI: very low |
||||
| Nutrient | Amount | DRI/DV (%) |
Nutrient Density |
World's Healthiest Foods Rating |
|---|---|---|---|---|
| vitamin E | 1.94 mg (ATE) | 13 | 2.0 | good |
| World's Healthiest Foods Rating |
Rule |
|---|---|
| excellent | DRI/DV>=75% OR Density>=7.6 AND DRI/DV>=10% |
| very good | DRI/DV>=50% OR Density>=3.4 AND DRI/DV>=5% |
| good | DRI/DV>=25% OR Density>=1.5 AND DRI/DV>=2.5% |