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While stringent standards have been set by the International Olive Oil Council and the United States Department of Agriculture to regulate the purity of olive oil sold in the U.S., according to a UC Davis study, a high percentage of the U.S. olive oil brands do not meet the legal standards to be sold as “extra virgin.” (1,2)
In many cases, the so-called extra virgin olive oil is diluted with various vegetable oils. Investigators have even found brands of extra virgin olive oil that contained no olive oil at all. (2) They found seed oils, like sunflower oil, diluted with a splash of chlorophyll and beta-carotene to look and smell like extra virgin olive oil. Worse, they found brands of extra virgin olive oil that were bleached, boiled and deodorized vegetable oils with a splash of olive oil to give an olive oil appearance. (3)
The University of California Davis scientists evaluated 186 local and imported brands of extra virgin olive oils that were randomly selected from retail shelves in California. They found that 73% of the brands failed the extra virgin olive oil test, based on one or more of the following poor manufacturing procedures: (1-3)
- Oxidation by exposure to high temperatures
- Adulteration with cheaper, highly refined olive oil
- Oils made from olives damaged from storage of the olives
- Oils pressed from over-ripe or highly processed olives
Editor’s Note: The UC Davis has been challenged by the North American Olive Oil Association, which found that only 2% of olive oil sold in U.S. retail outlets is adulterated.
Experts suggest checking for authenticity by making sure they are certified California organic, have a harvest and press date, and have a spicy-bitter aftertaste that bites the back of your throat.
Large manufacturers harvest the oils from numerous contract farmers with big industrial harvesters that damage the olive trees and branches, as well as the olives. The olives are then transported in trucks to large pressing sites, where they sometimes sit in the hot sun and are stored for days before being pressed. The olives will often become over-ripe, oxidized and rancid during this transport and waiting time.
New Research on Cooking With Olive Oil
There has been much confusion about the safety of cooking with olive oil, as many studies found the smoke point of olive oil to be quite low. New research suggests that high grade extra virgin olive oil is very stable at high heat and has a smoke point approaching 400 degrees Fahrenheit. (4)
Most of the smoke point tests have been done on low quality, likely adulterated olive oils that were purchased off a supermarket shelf. Studies done on verified high quality extra virgin olive oil have demonstrated low acidity, more stability, higher smoke point, higher resistance to oxidation, and longer shelf life compared to the inferior counterfeit oils on the market.
The stable properties of a high quality extra virgin olive oil are primarily due to the high content of the naturally-occurring antioxidants, called polyphenols. Refining the olive oils or taking the lower quality oils from later stages in the pressing process significantly reduces the polyphenol content of the olive oil – which is why ensuring you’re getting the highest quality olive oil is so crucial. In one study, certain store-bought olive oils had as much as five times the polyphenol content as other olives oils on the shelf. (1)
In a 2015 study on cooking with extra virgin oil, researchers found that frying with olive oil and water preserved the antioxidant content of the oil and the vegetables that were cooked and, in fact, boosted their antioxidant content. (5)
How to Guarantee the Best Olive Oil
A few years ago at LifeSpa, my team and I organized an olive oil taste test using the best olive oils we could source from around the world, including France, Italy, California and other countries. While there were amazing oils from Europe, the organic oils from California were undoubtedly the best-tasting. The winner of our taste test was from a small, family-owned farm in California, named Fandango.
After investigating why their oil was so good, we found out that just getting an organic certification in California is a major accomplishment due to the stringent toxin, heavy metal, and pesticide residue requirements laid out in the state’s Proposition 65.
At Fandango, on harvest day, the olives are hand-picked when they are perfectly ripe, thrown into a certified organic mobile mill on site, then pressed immediately into an oil. This process preserves the highest content of polyphenols and allows them to tout the lowest levels of oxidation on the market. Thank God for small farmers who care about quality, not quantity!
Over the years, the folks at Fandango have become good friends of ours, but LifeSpa has no business relationship with them other than we love and use their olive oil exclusively. Check them out at fandangooliveoil.com.
We RecommendDr. John’s Favorite Olive Oil
When sourcing olive oil, look for a harvest and/or press date. It is ideal to ingest the current year’s harvest. If it is a California olive oil, make sure it is certified organic by the California Certified Organic Farmers (CCOF) and be sure it has a seal certifying that the olive oil is certified extra virgin by the California Olive Oil Council (COOC).
If the oil is from Italy, look for a D.O.P. seal (Protected Designation of Origin), which means the olives are from where the label says.
Some Impressive Olive Oil Science Facts
- Seven tablespoons of high polyphenol olive oil raised HDL levels by 3 percent. (6)
- Two tablespoons of high polyphenol olive oil significantly improved endothelial function. (7)
- High-polyphenol olive oil enlarged HDL cholesterol particles, making them more heart-healthy. (6)
- High-polyphenol olive oil lowered blood pressure in adults aged 55-80. (8)
- High-polyphenol olive oil has been shown to cause toxic and unhealthy cells to self-destruct instead of divide. (9)
- New studies suggest that high quality extra virgin olive oil may protect against cognitive decline, bone density concerns, skin aging and premature death. (10)