Economic powers and lobbyists have made olive oil the oil of choice even though canola oil, for example, contains three times more omega-3 fatty acids. Either way, you should only use cold-pressed oils. There are a wealth of studies to support this. Dr. Dean Ornish and other American health researchers recommend avoiding oil in as much as is possible.
Constituents and nutritional value:
From Wikipedia: “Olive oil is composed mainly of the mixed triglyceride esters of oleic acid and palmitic acid and of other fatty acids, along with traces of squalene (up to 0.7%) and sterols (about 0.2% phytosterol and tocosterols). The composition varies by cultivar, region, altitude, time of harvest, and extraction process.”
“Natural olive oil contains oleocanthal and oleoropein, two antioxidants that are believed to have a number of health benefits.*”
“One tablespoon of olive oil (13.5 g) contains the following nutritional information according to the USDA: Calories: 119, Fat: 13.50 g (21% of the Daily Value, DV), Saturated fat: 2 g (9% of DV), Carbohydrates: 0, Fibers: 0, Protein: 0, Vitamin E: 1.9 mg (10% of DV), and Vitamin K: 8.1 µg (10% of DV).”
“The ratio of polyunsaturated to saturated fatty acids (P/S ratio) in olive oil is far below the recommended value of 1.0.*”
How companies influence the market:
“In order to obtain quantities large enough to dominate the market, Italian distributors purchased Tunisian, Turkish, and Greek oil in large amounts and transferred it illegally so that it could later be sold as ʽItalianʼ and also be approved in the EU. Olitalia found a different way. The company simply chose a name that suggests the oil is of Italian origin, but if you read the small print you will see that it is actually a mixture of oils from a number of EU countries.*”
“Journalist Tom Mueller has investigated crime and adulteration in the olive oil business, publishing the article "Slippery Business" in New Yorker magazine, followed by the 2011 book Extra Virginity. On 3 January 2016 Bill Whitaker presented a program on CBS News including interviews with Mueller and with Italian authorities. It was reported that in the previous month 5,000 tons of adulterated olive oil had been sold in Italy, and that organised crime was heavily involved—the term "Agrimafia" was used. The point was made by Mueller that the profit margin on adulterated olive oil was three times that on the illegal narcotic drug cocaine. He said that over 50% of olive oil sold in Italy was adulterated, as was 75-80% of that sold in the US. Whitaker reported that 3 samples of "extra virgin olive oil" had been bought in a US supermarket and tested; two of the three samples did not meet the required standard, and one of them—with a top-selling US brand—was exceptionally poor.”
Production and consumption:
“In 2013, world production of virgin olive oil was 2.8 million tonnes, a 20% decrease from the 2012 world production of 3.5 million tonnes. Spain produced 1.1 million tonnes or 39% of world production in 2013. ...
Although Italy is a net importer of olive oil, it produced 442,000 tonnes in 2013 or 16% of the world's production. ...
Australia now produces a substantial amount of olive oil. Many Australian producers only make premium oils, while a number of corporate growers operate groves of a million trees or more and produce oils for the general market.”
“Extra virgin olive oil contains small amounts of a natural nonselective COX2-inhibitor called oleocanthal, which has anti-inflammatory properties similar to those of Ibuprofen.
A laboratory study from 2008 took the position that because of the high content of oleic acid consuming olive oil may lead to an increased risk of arteriosclerosis and other cardiovascular diseases.*”
Note (italics): * = Translation from a German Wikipedia entry