Olive Oil Offers Unique Cardiovascular ProtectionApril 2015
By Marsha McCulloch, RD
Olive oil has been pinpointed as a major source of the cardiovascular benefits long associated with a Mediterranean diet.1,2 A recent study of a healthy Mediterranean population showed that olive oil consumption accounted for as much as a 44% reduction in cardiovascular deaths compared to those who didn’t use olive oil.3
But did you know that if you’re not consuming the right type or amount of olive oil, you might not be getting much benefit at all?
This is because different types of olive oil have varying amounts of polyphenols. Although olive oil’s health benefits have historically been attributed to its high monounsaturated fatty acid content, new evidence suggests it’s the polyphenols in olive oil, which have anti-inflammatory properties,4 that may contribute most to the oil’s cardiovascular benefits.4,5
Olive oil polyphenols have been shown to have direct actions in improving blood lipids and endothelial function, effects that support artery health and normal blood pressure.6,7 In turn, these benefits have been linked to reduced risk of heart attack, stroke, and sudden cardiac death.8-10
Now that we understand the specific components in olive oil that contribute to cardiovascular health, it gives new clarity to the best type of olive oil to consume and how often we should consume it to get the most benefit.
Beneficial Components Of Olive Oil
For years it was believed that olive oil’s cardiovascular benefits were derived from its high monounsaturated fatty acid content. This would have made sense, since olive oil is one of the oils highest in monounsaturated fatty acid, primarily oleic acid, which has been shown to increase high-density lipoprotein (HDL or “good”) cholesterol and decrease low-density lipoprotein (LDL or “bad”) cholesterol.8
A decade ago, the FDA even credited olive oil’s high monounsaturated fatty acid content as the underlying reason for the benefits associated with a study showing that consuming 2 tablespoons of olive oil daily reduces the risk of coronary heart disease.
But there’s a catch. If oleic acid were the main driver of olive oil’s expansive cardiovascular benefits, we’d see the same benefits with other oils high in oleic acid, such as canola oil. This is not the case, however.5
More recently, a rapidly growing body of research suggests it is the minor components of olive oil—specifically polyphenols, which comprise just 1-2% of the content of virgin olive oil—that may contribute most to the oil’s beneficial effects.4 To break that down even further, hydroxytyrosol is one of the polyphenols that occurs in the highest amount in olive oil and has been shown to have important cardiovascular benefits.6,7
A number of studies identify how olive oil polyphenols have direct actions in reducing cardiovascular disease risk.
Improves Lipid Profiles
One of the main ways that olive oil may reduce cardiovascular risk is by lowering total and LDL cholesterol. About a decade ago, in a study published in Medical Science Monitor, older adults who were given 2 tablespoons of extra-virgin olive oil daily for six weeks had an average 31.5 mg/dL reduction in their total cholesterol and a 30 mg/dL reduction in LDL cholesterol.9 They also experienced a significant decline in their total-to-HDL and LDL-to-HDL ratios.11
Since then, scientists have found strong clinical evidence that it’s the polyphenol content in olive oil that plays a significant role in olive oil’s ability to support healthy blood lipids.9 This was demonstrated by the Eurolive Study, a study specifically designed to assess olive oil’s health benefits.
For the study, healthy men took 25 mL (about 1½ tablespoons) of high-, moderate-, or low-polyphenol olive oil daily. After three weeks, consumption of high- polyphenol olive oil (virgin) reduced levels of oxidized LDL cholesterol by an average of 3.21 U/L, whereas low-polyphenol (refined) olive oil didn’t reduce oxidized LDL at all.12
Reducing oxidized LDL cholesterol levels is important because oxidized LDL is a very strong predictor of cardiovascular events, such as heart attack, even in apparently healthy individuals.13 When LDL is oxidized, it can easily enter the walls of the arteries, causing damage to the thin, interior lining of arteries called the endothelium and promoting inflammation, which are the early steps in atherosclerosis.13
The same Eurolive Study demonstrated that the polyphenols in olive oil increase beneficial HDL cholesterol. Those taking the high-polyphenol olive oil saw an average 1.74 mg/dL increase in HDL cholesterol, while those consuming olive oil with a medium polyphenol content saw a 1.22 mg/dL increase, and those consuming olive oil with a low-polyphenol content saw only a 0.98 mg/dL increase in HDL cholesterol.10 To put this in perspective, a 1 mg/dL increase in HDL has been associated with a 2-3% decrease in coronary heart disease risk.9
The greater the polyphenol content, the greater its ability to increase HDL cholesterol levels.12
Is Your HDL Cholesterol Functioning Properly?
While most people are familiar with the importance of raising HDL cholesterol levels, fewer are aware of the importance of boosting HDL function. In reality, HDL’s ability to reduce the risk of heart disease depends not only how much HDL is available, but also on how well it functions.14 Olive oil helps increase HDL and improves its function.
HDL’s job is to remove bad cholesterol from white blood cells called macrophages so that it can be eliminated from the body through bile, thus lowering overall cholesterol. How well HDL carries out this function is called HDL efflux capacity.
A 2012 human clinical trial found that olive oil polyphenols enhance the expression of genes that trigger this process.15 Two years later, Spanish researchers published the first direct evidence that consuming polyphenol-rich olive oil enhances HDL function. In a crossover study, when European male volunteers consumed 25 mL of polyphenol-rich olive oil daily for three weeks, they experienced a 3.05% increase in cholesterol efflux capacity.16 In contrast, consuming a low-polyphenol olive oil was associated with a 2.34% decrease in cholesterol efflux capacity.
The beneficial results seen in those consuming the polyphenol-rich olive oil diet may have been promoted by the increased number of polyphenols bound to HDL, protecting it from oxidation.16 Because oxidized HDL cholesterol is more rigid, it has a lower cholesterol efflux capacity.16
This same study showed that another way olive oil polyphenols help improve the function of HDL is by enhancing the size of HDL particles. This is beneficial because large HDL particles (called HDL2) are better able to remove cholesterol from arterial plaque compared to small HDL particles (called HDL3).16 The study showed that men who consumed polyphenol-rich olive oil had significantly higher HDL2 levels and significantly lower HDL3 levels.16
Another way olive oil exerts its beneficial cardiovascular effects is by improving endothelial function of arteries. Endothelial dysfunction, an early step on the path to coronary artery disease—and ultimately, heart attack and stroke—occurs when arteries are unable to perform in ways that help maintain healthy blood flow and normal blood pressure.17
Endothelial dysfunction has not only been found in patients with coronary artery disease, but also in those with type II diabetes, hypertension, obesity, high cholesterol, and metabolic syndrome (a cluster of conditions that increase the risk of cardiovascular disease and diabetes).18,19
In a 2013 double-blind clinical trial, US and Italian researchers found that consuming 30 mL (2 tablespoons) of polyphenol-rich olive oil daily for four months significantly improved endothelial function in adults with atherosclerosis.20
Excitingly, olive oil improves endothelial function in as little as two hours after consumption.20 However, plant polyphenols don’t stick around in the blood very long, so the study authors proposed that ingredients in olive oil likely alter the expression of long-term endothelial modulators, such as nitric oxide synthase.20 Endothelial nitric oxide synthase is an enzyme that generates nitric oxide (NO).21 Nitric oxide is a protective molecule that signals arteries to expand so blood can flow through more easily, thus lowering blood pressure.22
Even more encouraging is evidence that polyphenols in olive oil can interact with a hereditary gene variant of endothelial nitric oxide synthase (the NOS3 Glu298Asp polymorphism, which is a risk factor for hypertension and coronary artery disease), to improve endothelial function after meals.19 So, even if genetics are not in your favor, olive oil may help.
Hypertension (high blood pressure) is a major risk factor for coronary heart disease, congestive heart failure, and stroke.24 The most exciting news about olive oil’s effect on blood pressure isn’t simply that it helps reduce hypertension (which it does)—it’s that it does it so well that it could help eliminate the need for blood pressure drugs in some people.
In 2000, the first long-term study examined the effects of consuming a diet high in extra virgin olive oil might have on blood pressure and found that it could significantly decrease hypertension medication requirements.24 In this crossover study, adults taking antihypertensive medication who were given olive oil for six months had a 48% decrease in antihypertension medication requirements compared to only a 4% decrease in antihypertension medication dosage requirements when consuming a diet high in polyunsaturated fat from sunflower oil, which does not have the same rich polyphenol content as olive oil.24
As an added bonus, eight people following the olive oil-rich diet were eventually able to control their hypertension without any medication at all, while no one following the sunflower oil-rich diet was able to discontinue blood pressure medication.
Recent research has helped uncover at least part of the reason for olive oil’s effects on blood pressure—and it points right back to its polyphenol content. In a one-year study of participants in the PREDIMED (Prevention with the Mediterranean Diet) trial, which included adults 55 to 80 at high risk of heart disease, the researchers found that increased extra virgin olive oil intake, as part of a Mediterranean diet, decreased blood pressure through high polyphenol consumption.25
Rather than relying only on dietary reports of participants’ extra virgin olive oil consumption (which are historically unreliable), the researchers were able to confirm polyphenol intake by measuring total polyphenol excretion in the urine. Taking this one step further, the scientists were able to link increased polyphenol excretion (indicating increased total polyphenol intake) with increases in plasma nitric oxide, which, as described earlier, signals blood vessels to expand and relax, thus lowering blood pressure.
The benefits of olive oil not only come from its rich profile of monounsaturated fatty acids, but most likely even more so from the natural compounds, including polyphenols, that olive oil maximally possesses when unrefined.
Studies have shown that polyphenols in olive oil, including hydroxytyrosol, can help reduce oxidation of LDL cholesterol, thus helping to protect against atherosclerosis. Olive oil polyphenols have also been found to increase HDL cholesterol levels and improve its ability to remove cholesterol from arteries for transport to the liver and eventual elimination through the bile.
Adding another layer of cardiovascular support, polyphenol-rich olive oil has been found to improve the function of the endothelium of arteries, increasing release of nitric oxide, which signals blood vessels to relax and helps lower blood pressure. Research also suggests regular intake of high-polyphenol olive oil may help reduce requirements for blood pressure medication.
Because olive oil is a natural product, its polyphenol content is dependent upon a number of factors such as the age of the olives used, growing conditions, processing conditions, soil, temperature etc. Since extra virgin olive oil is the first pressing and uses the finest olives, it is assumed that this type of oil contains the highest polyphenol content.
Health conscious individuals should thus use extra virgin olive oil whenever possible as part of their diet. High potencies of olive oil polyphenols have long been contained in dietary supplements used by most Life Extension members.
If you have any questions on the scientific content of this article, please call a Life Extension® Wellness Specialist at 1-866-864-3027.
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