Source: nationalgeographic.com.
Most people know that the Mediterranean diet is one of the healthiest eating plans because it’s packed with fruits and vegetables. But many experts claim that the secret sauce of this underrated diet is the abundant use of extra virgin olive oil as the main added fat.
Although all fruits and vegetables have beneficial health compounds, those in olive oil, called phenols, are especially potent, says Mary Flynn, a nutrition researcher and founder of the Olive Oil Health Initiative, a non-profit organization at Brown University (United States). It has been found that the nutrients in extra virgin olive oil are beneficial for numerous diseases, such as heart disease and diabetes.
“I call the Mediterranean diet a plant-based diet based on olive oil,” says Flynn, who recently published a review of the science behind olive oil and found dozens of high-quality studies supporting its healthy effects. “There is no food or medication that can do what olive oil does,” she says.
The phenols in extra virgin olive oil are antioxidants, capable of protecting the body’s cells from harmful molecules, and they also have antimicrobial properties, says Selina Wang, a food science researcher at the University of California Davis (USA) and former research director at the Olive Center at the school, which has received funding from olive oil growers and processors in the state.
Like orange juice, extra virgin olive oil is nothing more than olive juice, although it undergoes testing to ensure it meets quality standards, such as not smelling or tasting rancid, which would indicate that the compounds providing health benefits have degraded.
“Olive oil is one of the few foods that has a sensory component in its quality standards,” says Wang.
In Greece, Italy, Spain, and other parts of the Mediterranean where olive trees have been growing for thousands of years, oils were traditionally extracted with hot water, applied after picking and crushing the fruit, a process that damaged some of the phenols. In modern times, manufacturing protocols were revised when it became clear that a cost-effective way to extract the oil from the fruit while keeping the phenols intact was to centrifuge it at room temperature (and without chemical solvents, as was sometimes done). Oils processed this way carry the popular label “extra virgin.”
The most studied phenols in olives, called secoiridoids, include their natural derivatives oleocanthal, oleacein, oleuropein, ligstroside, aglycone, and oleomissional. But what really matters is that the combination acts synergistically.
A tasty and powerful medicine
In places where the Mediterranean diet has been firmly established for a long time, the rates of many diseases are lower, and many experts believe that extra virgin olive oil is one of the main reasons.
Heart diseases. During a 10-year study conducted in Spain with over 12,000 people, researchers found that the risk of dying from cardiovascular disease was halved in people who consumed a tablespoon and a half of extra virgin olive oil per day. Researchers noted that this was not the case with “refined” olive oil that was not extra virgin.
High blood pressure, which contributes to heart diseases, specifically benefits from extra virgin olive oil, and a study found that systolic blood pressure decreased after three weeks of consuming two tablespoons daily.
“Many people could reduce or stop taking their blood pressure medication” by increasing their consumption, says Flynn.
Breast cancer. When 4000 Spanish women were randomly assigned to one of three forms of the Mediterranean diet: a low-fat plan; another supplemented with nuts (another healthy fat); and one with extra virgin olive oil, the women who consumed extra virgin olive oil recorded the lowest rates of breast cancer during the five-year study period.
Another study compared the eating habits of over a thousand Spanish women with invasive breast cancer with a similar group without the disease and concluded that consuming more than two tablespoons of extra virgin olive oil per day during meals offers the greatest protection.
Diabetes. More than a dozen randomized trials have documented the oil’s ability to reduce blood glucose, according to Flynn’s review. Some researchers believe it does so by reducing damage to the insulin-producing cells of the pancreas.
Cognitive impairment. Studies in mice and a small randomized clinical trial in people with mild cognitive impairment have linked the consumption of extra virgin olive oil to the removal of some amyloid plaques and improvement in cognitive function, although experts emphasize that larger studies are still needed.
Weight loss. It seems contradictory because oils are calorie-dense, but several dozen women randomly assigned to a low-fat plant-based diet or one adding more than three tablespoons of extra virgin olive oil daily found that the latter were much more likely to lose more than five percent of their body weight after eight weeks. When asked if they would continue with the plan, many more from the oil group said yes. “Compliance is the biggest problem with diets, so this is significant,” says Flynn, the study’s lead author.
It’s more than monounsaturated
The U.S. federal dietary guidelines (and those of many other countries) do not distinguish between cooking oils, apart from recommending that consumers limit saturated fats found in red meat and palm oil, which have been linked to health problems, laments Flynn. The case is different in Spain as the Ministry of Consumption specifically recommends using “olive oil in all meals, as a dressing and in food preparation.”
However, polyunsaturated seed oils commonly used by many cooks, such as safflower, sunflower, corn, and soybean oils, have their own problems. The most notable is that they are subject to a higher rate of chemical reactions (known as oxidation) that degrade their quality compared to extra virgin olive oil.
And like other monounsaturated fats for cooking, such as canola oil, they don’t have the same healthy effect, attributing all the benefits of extra virgin olive oil to its monounsaturated fats and not to its phenol content is a mistake, says Flynn.
Another misconception is that extra virgin olive oil cannot be cooked well with because the oil smokes at low temperatures, but it actually produces fewer unhealthy byproducts when heated compared to other oils, researchers have found.
Choose your olive oil carefully
Health isn’t the only reason to increase olive oil consumption. High-quality, well-stored olive oil also tastes great.
We call olive oil “liquid gold” for its flavor and versatility, as well as being healthy, says Joy Pierson, a chef and restaurateur who, with her husband Bart Potenza, founded the famous vegan restaurant Candle 79 and others in New York (USA), and now mentors other chefs specializing in vegan cuisine.
The couple uses extra virgin olive oil to dress and cook all kinds of dishes, from dressings, marinades, and pestos to sautés, pan-fried potatoes, roasted and grilled vegetables, and even cakes.
In the United States, many people buy the extra virgin olive oil they find in the supermarket, but that’s a mistake, says Pierson. Oils have unique flavors depending on the company, climate, soil in the growing region, and many other parameters, which are especially important when the oil is not cooked. She also prefers organic varieties.
Pierson recommends going to a local farmers’ market or a gourmet store where you can try various brands. She also suggests buying more than one, with a mild-flavored product for sautés or cakes and another with more bite for a food like polenta.
“If olive oil mattered to us as much as wine, we’d make the same purchases,” says Wang.
Potenza recommends checking the websites of extra virgin olive oil producers before deciding on a brand. “They will use descriptors like soft or herbaceous notes, similar to the flavor profiles of good wines. It’s exciting,” he says.
Another important piece of information that can be found on many websites is how quickly their olives go from picking to oil production, something that, according to experts, should happen within hours to keep products fresh and phenols high. California, which has only been producing extra virgin olive oil on a large scale for a few decades, uses a modern method where special dwarf trees are planted very close together to allow for quick machine harvesting.
Kiara Koutoulakis, communication and sales manager at the extra virgin olive oil manufacturer Koronekes, on the Greek island of Crete, says high-quality olive oil companies that handpick also aim for that timeline. “The fresher, the better,” she says. “Olives are a very fragile fruit.”
Koronekes also picks its olives early in the harvest, before they turn black, when their phenols are shown to be at their peak, she says.
Since large manufacturers extract the oil by centrifugation, you won’t see the term “first cold press” on big brands. But small companies like Koronekes, which continue to press their olives, use that term to distinguish the initial batch, the tastiest.
How to store extra virgin olive oil
Once you bring the bottle home, time is of the essence.
“I always say that extra virgin olive oil loses its virginity over time,” says Wang. The product may have a two-year expiration date, but once opened, extra virgin olive oil should be considered a perishable product and consumed within four months, she says.
Never store the oil near heat, or near or above the oven, as many people mistakenly do, says Flynn. And don’t leave it uncovered for too long while preparing food because oxygen is the enemy of its phenols.
The bad news about extra virgin olive oil is that its price, at least in the United States, is about to rise substantially due to floods, wildfires, droughts, frosts, and other issues with olive harvests worldwide (curiously, in Spain, despite being a leading country in consumption and production of olive oil, the price has skyrocketed more than in any other European country this year). While it’s best to buy it fresh, if you want to stock up while prices are lower, store the product in a cool, dark place or, if you won’t open it for several months, in the freezer or refrigerator, Wang recommends.
But don’t take it out until you’re ready to use it and avoid refrigerating it again. “If the oil repeatedly has to return to room temperature, it can change its flavor and appearance,” she says.
Source: nationalgeographic.com