Olive oil and vegetables are two of the foods most closely associated with the traditional Mediterranean diet.
A large Italian study took a closer look at both and found that women who consumed more olive oil and leafy green vegetables experienced a lower incidence of coronary heart disease during approximately eight years of follow-up.
The findings don't prove that either food was solely responsible for the difference, but they add to the much larger body of research examining Mediterranean-style eating and cardiovascular health.
Nearly 30,000 Women Followed
Researchers analyzed dietary information from 29,689 Italian women participating in the European Prospective Investigation into Cancer and Nutrition, better known as EPIC.
The women were approximately 50 years old on average when the study began.
Researchers collected information about their diets and followed them for an average of nearly eight years.
During that period, 144 major coronary heart disease events occurred, including heart attacks and coronary revascularization procedures.
Researchers then compared those outcomes with the women's reported eating habits.
Olive Oil Consumption Stood Out
Women consuming more than 31 grams of olive oil per day—roughly two tablespoons—had a substantially lower incidence of coronary heart disease than women consuming 15 grams or less per day.
After researchers adjusted for other cardiovascular risk factors, higher olive oil consumption was associated with approximately a 44% lower risk.
That's a significant association.
But it's important to understand what that number means.
The study was observational. Researchers weren't assigning women to consume specific amounts of olive oil and measuring the result.
That means the study identified an association rather than proving that olive oil itself caused the reduction in heart disease.
Leafy Green Vegetables Were Also Associated With Lower Risk
Researchers found a similar relationship with leafy vegetables.
Women consuming more than one serving per day of leafy vegetables had approximately a 46% lower risk of coronary heart disease compared with women consuming no more than two servings per week.
The foods included leafy vegetables such as lettuce, spinach, endive and chard.
Researchers suggested that nutrients naturally present in these vegetables—including folate, potassium and antioxidant compounds—could potentially contribute to cardiovascular benefits.
Why Were Researchers Interested in Olive Oil?
Olive oil is naturally high in oleic acid, a monounsaturated fatty acid.
Virgin and extra virgin olive oils also retain naturally occurring phenolic compounds, which we generally refer to as Biophenols.
Both have become important subjects of cardiovascular research.
But olive oil is also important because of what it can replace.
Using olive oil in salad dressings, cooking and other foods can replace sources of saturated fat such as butter.
That's something subsequent research has continued to investigate.
One Study Isn't the Whole Story
This study was published in 2010, so it shouldn't be presented today as new evidence.
What makes it interesting now is how it fits into the research that followed.
Larger and longer-term studies have subsequently found associations between olive oil consumption and cardiovascular health, while randomized research involving Mediterranean dietary patterns has provided additional evidence supporting diets rich in extra virgin olive oil.
So this Italian study represents an earlier piece of a research story that has continued to develop.
There Were Limitations
The researchers themselves identified several important limitations.
Dietary intake was based on information reported by participants, which always introduces the possibility of inaccuracies.
People's diets can also change over time.
And because this wasn't a randomized clinical trial, other lifestyle and dietary differences could have contributed to the results.
There's another important distinction for us:
The study measured olive oil consumption rather than specifically testing Ultra Premium or even exclusively extra virgin olive oil.
We shouldn't turn a general olive-oil finding into an EVOO-specific claim when the study didn't establish that distinction.
The Mediterranean Diet Is About More Than One Food
There's another reason I like this particular study.
It reminds us not to turn olive oil into a magic ingredient.
Traditional Mediterranean-style eating combines olive oil with foods such as vegetables, legumes, whole grains, nuts, fruits and other minimally processed foods.
Here, both olive oil and leafy green vegetables were independently associated with lower coronary heart disease risk.
That makes for a much more useful message than simply saying, “Eat olive oil and you'll protect your heart.”
Try using a quality olive oil with the vegetables.
A drizzle over roasted vegetables, a vinaigrette over leafy greens or EVOO used to sauté vegetables puts the two foods together naturally—and tastes pretty good, too.
The Takeaway
In a study following nearly 30,000 Italian women for approximately eight years, researchers found that women consuming greater amounts of olive oil and leafy green vegetables had a lower incidence of coronary heart disease.
Women with the highest reported olive oil consumption had approximately a 44% lower risk, while higher leafy-green consumption was associated with approximately a 46% lower risk.
Because the study was observational, it cannot establish that olive oil or leafy greens directly caused those reductions.
What it does provide is another piece of evidence supporting a dietary pattern that researchers have continued to study extensively:
Olive oil and vegetables belong together—both on the plate and in the conversation about Mediterranean-style eating and cardiovascular health.
Research Source
Bendinelli B, Masala G, Saieva C, et al. Fruit, vegetables, and olive oil and risk of coronary heart disease in Italian women: the EPICOR Study. American Journal of Clinical Nutrition. 2011;93(2):275–283.
This article is for educational purposes only and is not intended to diagnose, treat, cure or prevent any disease or replace individualized medical advice.
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