Olive oil is one of the healthiest cooking oils because it is packed with nutrients and antioxidants. Numerous studies provide evidence of the olive’s ability to prevent disease and promote well being. But recent reports indicate that more than half the olive oil on the supermarket shelf is not what the label says. Extra virgin olive oil, the highest quality that provides the most health benefits, is often still “virgin” but it doesn’t pass the “extra virgin” test.
Studies of the sensory quality and chemical content of olive oil indicate two primary concerns for anyone who uses olive oil for its health benefits. First, extra virgin olive oil may be adulterated with cheaper refined olive oil or it may be diluted with other less expensive oils such as soybean or hazelnut. If the olive oil is adulterated with other seed or nut oils, its quality and taste are compromised and it is no longer “extra virgin.”
If the oil has cheaper olive oil added to it, quality and taste will again be compromised, but it may have gone through an oxidation process meaning it will contain a greater content of free radicals, which can damage tissues in the body. The poor quality of olives used to make refined oils make them “not fit for human consumption” according to the International Olive Committee (IOC) and the USDA. But, that’s just the oil that you may be innocently purchasing because it has a fraudulent “extra virgin” label!
Studies Show More than 50 Percent of Imported Olive Oil Is Not Extra Virgin
New evidence shows that more than 50 percent of olive oil on the market is not what the label claims. A study by the University of California at Davis Olive Center, in conjunction with other recent studies and media reports, have shown that many of the bottles labeled “extra virgin olive oil” on supermarket shelves have been adulterated and shouldn’t be classified as extra-virgin. Perhaps even more concerning than the fact that many consumers are forking out big money for poor quality or adulterated cheap oil is that these versions don’t provide the health benefits and are, in fact, unhealthy.
With fewer sterols and polyphenols (the protective antioxidants naturally found in olives), more oxidized fats, and fewer “good” fatty acids, adulterated or poor quality olive oil becomes the kind of fat you want to avoid.
The report from UC Davis comes on the heels of other studies that document poor quality and contaminated olive oil, both from domestic U.S. producers and foreign olive oil companies. You may be surprised to find that imported olive oil is much more likely to be fake or bad quality—the UC Davis report found that 69 percent of imported olive oil that was labeled as extra virgin failed to meet quality and authenticity standards from the USDA and the IOC.
The term “extra virgin olive oil” means the olives used to make the oil are of a certain quality, the oil has been made from olives crushed in a certain way, contains no more than 0.8 percent acidity, and has not been refined with chemical solvents or high heat. Naturally, it shouldn’t have other oils such as hazelnut or soy oil added to it. Extra virgin olive oil should have distinct sensory flavors, and experienced tasters should be able to distinguish the between low and high quality “extra virgin” and between extra virgin, virgin, and olive oil that’s been adulterated with other oils.
A Long History of Olive Oil Fraud
To meet the extra virgin standard is a costly process, which has led to fairly widespread olive oil fraud. In fact, the history of olive oil schemes appear to date back over two thousand years due to its utility in soaps and lotions (the health benefits extend to the skin and hair as well as the organs and tissues). Adulteration with cheaper oils appears to be the most common scam because fake oil is easy to pass off to innocent consumers. But with the growing demand for extra virgin olive oil, producers and marketers began labeling poorer quality olive oils as extra virgin.
UC Davis Study Shows 69 Percent of Imported Olive Oil Doesn’t Measure Up
The UC Davis study tested 14 imported and 5 California-grown brands with the extra virgin label from supermarkets in three different areas of California. They tested the oil for quality based on standards from the IOC and USDA, and then performed additional tests to determine the total polyphenol content and levels of oxidized fats.
Consuming oxidized fats is concerning because they are the kind of fat that can accelerate the buildup of plaque in the arteries that will lead to atherosclerosis. Oxidized fats from animals such as pork, chicken, and beef are likely more detrimental to health, but there is evidence that plant-based oxidized fats, particularly corn and cottonseed oil, may contribute to health problems as well. Of course, if you’re paying for what it supposed to be a high quality extra virgin olive oil, you don’t want it to contain oxidized fats before you even remove the cap.
The polyphenols are one type of antioxidants that are found in the olive, and of course you want to have higher quantities to reap the greatest health benefits from your oil. Lower levels of polyphenols indicate the content of oxidized free radicals in the oil that make the oil “unhealthy.” Just as you want olive oil to have a high antioxidant content so that it can fight inflammation and neutralize radicals, you do not want the oil to contain free radicals that cause inflammation in the body. Plus the presence of oxidized compounds and low amounts of polyphenols indicate that the oil may be rancid, impure, refined, or contain other oils.
Of the imported olive oil samples in the UC Davis study, 69 percent did not meet the IOC/USDA standards for extra virgin olive oil, whereas 10 percent of the California-grown olive oils did not. The faulty oils were found to have an average of 3.5 sensory defects such as “rancid, fusty, and musty,” and should have ben classified at the lower grade of “virgin.” The sensory defects indicate the oil was oxidized, poor quality and adulterated with cheaper refined oils.
The only positive finding from the study was that based on the fatty acid and sterol profiles of the oils, it is likely the adulteration was from cheap refined olive oil rather than other nut, seed or vegetable oils. This is “positive” because if the oil had been adulterated by oils other than olive, it indicates more severe production fraud, and with the rise of nut and seed allergies, passing hazelnut or peanut oil off as olive oil can have immediate and serious health consequences.
The imported olive oil brands that demonstrated defective flavors and poor chemical content included:
365 100% Italian (Whole Foods brand)
Safeway Select Brand
Newman’s Own Organic
Remember, there were three samples of each brand from stores across California, and not all of the samples failed the extra-virgin test. For example, all three samples of Bertolli, Pompeian, Carapelli, Mezzetta, and Mazola failed, whereas only two samples of the Rachael Ray, Safeway, and 365 brands failed (see the chart below). Of the imported brands, Kirkland Organic performed the best with all three samples ranking in as “extra virgin.”
The California-grown brands performed much better. Only one sample of Bariani oil failed the extra virgin test. McEvoy Ranch Organic, California Olive Ranch, Lucero, and Corto Olive all passed with flying colors. These brands are all available directly from each company and can also be found in gourmet stores and some supermarkets. Naturally, they cost more than the olive oils that failed the test—all of which you can buy for less than $10.
Tomorrow, I will provide strategies for buying the best extra virgin olive oil.
Perez-Herrera, A., Delgado-Lista, J., et al,. The Postprandial Inflammatory Response After Ingestion of Heated Oils in Obese Persons is Reduced by the Presence of Phenol Compounds. Molecular Nutrition and Food Research. December 2011. Published Ahead of Print.
Escrich, E., Moral, R., et al. Olive Oil, An Essential Component of the Mediterranean Diet, and Breast Cancer. Public Health Nutrition. December 2011. 14(12), 2323-2332.
Erol, O., Arda, N., et al. Protective Effects of Olive Oil Phenolics and Gallic Acid on Hydrogen Peroxide-Induced Apoptosis. European Journal of Nutrition. November 2011. Published Ahead of Print.
Frankel, Edwin. Chemistry of Extra Virgin Olive Oil: Adulteration, Oxidative Stability, and Antioxidants. Journal of Agricultural and Food Chemistry. 2010. 58, 5991-6006.
Mueller, Tom. Slippery Business. The New Yorker. 13 August 2007.
Perez-Jimenez, F., Cienfuegos, G., et al. International Conference on the Healthy Effect of Virgin Olive Oil. European Journal of Clinical Investigation. 2005. 35, 421-424.
Manning, P., De Jong, S., et al. Paraoxonase 1 Activity in Chylomicrons and VLDLL: The Effect of Type 2 diabetes and Meals Rich in Saturated Fat and Oleic Acid. Lipids. December 2011. Published ahead of Print.
Khalaltbary, A., Ahmadvand, H. Neuroprotective effect of Oleuropein Following Spinal Cord Injury in Rats. Neurological Research. 2012. 34(1), 44-51.