Contrary to what you may have heard, olive oil does not lose its health benefits or be unhealthy when heated.
Olive oil has been used for cooking for thousands of years. It is a cornerstone of the Mediterranean diet. So why do some people think that olive oil should not be used for cooking? One persistent rumor is that olive oil will lose its health benefits when heated. This rumor is false. Here's why:
First, olive oil's main health benefit is its fat composition. Olive oil is mostly monounsaturated fat. Cooking with an oil won't change its fat makeup. Olive oil's percentage of monounsaturated fat remains the same after heating, even to high temperatures.
According to the American Heart Association, monounsaturated fats can help reduce bad cholesterol levels in your blood that can lower your risk of heart disease and stroke. They also supply nourishment to help grow and maintain your body's cells.
The Food and Drug Administration (FDA), in 2004, approved a health claim for olive oil over the basis that the monounsaturated fat in olive oil may reduce the risk of coronary heart disease when used in place of saturated fat.
All olive oils, whether extra virgin or refined, heated or raw, contain a comparable amount of monounsaturated fat.
What about trans fats?
Cooking oils, even when heated, may form small amounts of trans fats. On the other hand, the concentration is minuscule -- less than 1% - even with prolonged heating.
The smoke point myth
All olive oil has relatively high smoke point (between 365 and 410 F) that is generally not impacted by household cooking. But smoke point is not the most important factor when evaluating a cooking oils suitability for cooking.
The vital issue in comparing oils is oxidative stability--the point to which a cooking oil resists breaking down under heat, which may result in the formation of potentially harmful compounds.
Research has found that extra virgin olive oil is the most stable cooking oil under heat in regards to the creation of polar chemicals, outperforming cooking oils that have a higher smoke point. 1 reason for this is that olive oil contains phenols and antioxidants that protect it from breaking down when heated.
Another important factor is the fatty acid composition of the oil (monounsaturated fats such as olive oil resist oxidation better than polyunsaturated fats such as soy and corn).
And another important factor appears to be the degree to which the oil has already been exposed to heat from refining (most other commercially available cooking oils like canola, soy, corn, sunflower, etc.) have been refined from the production process, unlike EVOO that has not been refined.
This new research is consistent with a 2004 study where measured potentially harmful aldehydes generated when extra virgin olive oil, olive oil and canola oil were heated into 464°F. The study found that both extra virgin and regular olive oil performed greater than canola oil, even though canola oil ha a higher smoke point.
Furthermore, it is not likely that you will exceed the smoke stage of olive oil when cooking. Stovetop cooking does not usually 350ºF, even if you turn the burners to high and even if you turn up your oven to 450ºF, the food and petroleum does not reach that temperature.
Watch this demonstration to learn more and learn more about the research here.
Antioxidants and Polyphenols
You may have also heard that you shouldn't cook with olive oil because the phenols will probably be ruined by the heat--this is also not true. It is correct that phenols in olive oil are sensitive to heat. However, a 2015 study made a remarkable discovery. When cooking with extra virgin olive oil, the phenols go into the food. Potatoes fried in EVOO contained more phenols and antioxidants than potatoes boiled in water.
Furthermore, a 2020 study from the University of Barcelona in the Journal Antioxidants confirmed that extra virgin olive oil retains significant amounts of these healthy compounds during cooking.
What about the taste?
The flavor compounds in olive oil are delicate and will evaporate when heated. Heating olive oil does not damage the health benefits but it is going to make the olive oil lose some flavor. Some people consider this is a good thing as they do not want their foods to taste such as olive oil. However, if you have an expensive olive oil using complex flavors, you may want to save it for finishing and chilly uses.
In summary, olive oil is safe to cook . Heating olive oil won't ruin the health benefits or turn olive oil unhealthy. You can feel confident with olive oil in all of your recipes.
Olives at the "Heart" of a Heart-Healthy Diet
A wealth of research on the Mediterranean-style diet indicates that it has great potential to fight against many chronic diseases of aging. Individuals in the Mediterranean area who eat this traditional diet have a very low incidence of cardiovascular disease and high life-expectancy rates.
Olive oil is a key component of this diet, and researchers are delving into the chemical make-up of this oil to unravel just how it may give rise to a long and healthy life.
The fatty acids found in olive oil - called mono-unsaturated fats - are regarded as responsible for much of its heart benefits. Olive oil is abundant in beneficial oleic acid, and reduced in significantly less healthy saturated fats.
But researchers are finding that it's not just the fatty acid composition of this oil that's healthful. Other components may be just as important. And not just for the heart, but for colon and bone protection too.
Olive Polyphenols: Heart Health & Beyond
Along with its less artery-clogging fatty acids, olive oil contains antioxidants such as vitamin E and poly-phenols - plant compounds with potent antioxidant properties. These chemicals are produced in the fruit and leaves of the olive tree, where they afford protection against environmental stresses.
Some of the polyphenols particular to olive oil such as oleuropein are being intensely investigated. Early findings indicate that oleuropein and other phenols may work synergistically with the fats from olive oil to protect arteries, bones and colon cells.
Researchers have found that olive oil polyphenols promote the antioxidant capacity of blood and assist the inner lining of small blood vessels in volunteers become more responsive to sudden changes in blood flow (1,2).
Inadequate vessel responsiveness is considered an early warning sign of cardiovascular disease. High doses of olive leaf extract with oleuropein are reported to protect against ischemia in animals and reduced blood pressure in humans (3,4) - effects that might help explain olive oil's apparent heart benefits.
Colon Cell Protection
Though restricted, some population-health studies have pointed to olive oil as protective against colon cancer. As with heart disease, the possible anti-cancer effects of olive oil have been attributed to the high levels of monounsaturated fats. But, newer research is focusing on the role that the polyphenols may play (5).
For instance, researchers in Ireland report that olive oil polyphenols added to cultured colon cancer cells protected the cells from DNA damage(6). This lab study, that must be confirmed in animals and humans, also found that the polyphenols interrupts the invasive activity of the cancer cells.
Anti-inflammatory Effects May Benefit Bones
Inspired by studies suggesting that people eating a traditional Mediterranean diet are less likely to have osteoporosis, French investigators have begun to explore the effects of olive oil polyphenols on bone.
In 1 study, elevated levels of isolated oleuropein ceased bone loss in an animal model that mimics menopausal osteoporosis(7). Inflammation plays a role in bone loss, and oleuropein has anti-inflammatory as well as antioxidant action. This is exciting and promising work.
Go For the "Extra Virgin"
We all know now that olive oil is greater than just oleic acid. But to reap its potential benefits, choose extra virgin olive oil. Refined olive oils loose much of their poly-phenol content during processing, while cold pressed virgin oils retain these health-promoting chemicals.
