Virgin Olive Oil and Dietary Fats
Dietary fats are bad for you – right?
HSI members aren’t going to fall for that one. As members and other e-Alert readers are well aware, there are good fats and bad fats, but an overall avoidance of fats is simply an unhealthy idea. In fact, I’ll go one better: It’s nutritional insanity.
For instance, if you banished monounsaturated fats from your diet, you’d miss out on the heart health benefits of olive oil. A new study from Spain shows just how important those benefits can be.
In a previous e-Alert, I told you about research from the University of Barcelona, which reported that virgin olive oil contains high levels of vitamin E and plant chemicals called phenols. Phenols contain flavonoids; biologically active compounds that are high in antioxidants. The study concluded that virgin olive oil may inhibit the oxidation of LDL cholesterol.
That theory was put to the test in a new study from the EUROLIVE research group, also headquartered in Barcelona. The EUROLIVE team designed a study to examine the effect of olive oil phenols on cholesterol levels.
- Researchers divided 200 healthy male volunteers into three groups
- Each group received 25 mL of olive oil per day (25 mL = about six teaspoons)
- The 25 mL dosage was used because that’s the estimated average daily intake of olive oil in Mediterranean countries
- Each group received a different type of olive oil with different phenol levels: high, medium, and low
- This was a crossover study in three phases – the first three-week phase was followed by a two-week washout period (no consumption of olive oil), which was then followed by another three-week phase with each group switching to a different type of olive oil, then the cycle was repeated for a third phase
- Blood samples were taken from subjects throughout the three phases
Results showed that HDL cholesterol increased with consumption of high phenol olive oil, but not with the two lower phenol oils. More importantly, the ratio of total cholesterol to HDL dropped when olive oil with high phenol content was consumed.
The report of this study in the Annals of Internal Medicine emphasized the cholesterol angle. This makes sense, of course, because most of the medical community is still fixated on cholesterol when it comes to heart health. But just as important were these two results: 1) Triglyceride levels decreased in all three groups, and 2) Oxidative stress markers decreased with intake of high phenol olive oil.
All of the types of olive oil
In a nutshell, the EUROLIVE study shows that olive oil is good for your cardiovascular system, especially when phenols are high. And phenols are highest in extra virgin olive oil. So, when you shop for olive oil, why is extra virgin the most expensive type? It’s all about the processing.
Extra virgin olive oil is made from the first press of freshly harvested olives. The olives are cold-pressed, which means that no heat or chemicals are used in the process. The result is an oil with very low acidity and high levels of phenols, flavonoids and vitamin E. In short: all the good stuff.
The other varieties of olive oil – in order of increasing acidity:
- Virgin olive oil – like extra virgin, virgin comes from the first pressing, but has a slightly higher acidity
- Fino olive oil – a blend of extra virgin and virgin
- Olive oil (sometimes called “pure olive oil”) – a blend of refined olive oil (pressure, heat, and chemicals are used in processing) and virgin
- Light olive oil – olive oil produced by a filtration process that lightens the color and flavor, which many prefer for cooking
These are the olive oil basics. But like wine, olive oils have a wide variety of colors and flavors, depending on the types of olives used and cultivation factors such as climate and soil conditions, which vary dramatically throughout the Mediterranean region where olive oil is primarily produced.
“The Effect of Polyphenols in Olive Oil on Heart Disease Risk Factors” Annals of Internal Medicine, Vol. 145, No. 5, 9/5/06, annals.org