Updated October 30th 2020
Continuing our series on the health benefits of Extra Virgin olive oil as part of a healthy diet we look at the impact on blood pressure.
What is blood pressure?
Blood pressure is a measure of the force that your heart uses to pump blood around your body. Blood pressure is measured in millimetres of mercury (mmHg) and is given as 2 figures: systolic pressure – the pressure when your heart pushes blood out; diastolic pressure – the pressure when your heart rests between beats. For example, if your blood pressure is “140 over 90” or 140/90mmHg, it means you have a systolic pressure of 140mmHg and a diastolic pressure of 90mmHg.
As a general guide, ideal blood pressure is considered to be between 90/60mmHg and 120/80mmHg. High bp is considered to be 140/90mmHg or higher, low bp is considered to be 90/60mmHg or lower.
It is often related to unhealthy lifestyle habits, such as smoking, drinking too much alcohol, being overweight and not exercising enough. Left untreated, high bp can increase your risk of developing a number of serious long-term health conditions, such as coronary heart disease and kidney disease.
Blood pressure and why it matters
Blood travels from the heart via arteries to smaller arterioles, then to capillaries or sinusoids, to venules, to veins and back to the heart. Blood pressure refers to the force pushing outward on the walls of your arteries. The more forcefully that the blood pumps, the more that the arteries are required to stretch to allow the blood to easily flow. Over time, if that force is too great, the tissue that makes up the arterial walls can become stressed and damaged.
This can lead a wide range of problems. For example, it makes arteries more vulnerable to infiltration and accumulation of cholesterol. It also can destabilize any existing arterial plaques which increases the risk of them rupturing and inducing heart attacks.
So, high blood pressure is a really big deal. High blood pressure is often characterized as a “silent killer” because it can cause permanent damage throughout the body without any obvious symptoms. Tragically, by the time the problem becomes obvious, it is sometimes too late to reverse the damage.
About 70 million adults in the US have hypertension – that’s 1 in every 3! and only around 52% of people with hypertension have it under control. It is also likely that many are walking around with the condition who don’t even know they have it.
Healthy blood pressure levels are an indicator of how clear the body’s arteries are. When blood pressure levels get out of balance, they can signal a potential heart attack or stroke. High bp levels are often caused by atherosclerosis, also called hardening of the arteries, which occurs when oxidized particles of LDL cholesterol stick to the walls of the arteries. Eventually these particles build up and form plaque, narrowing the blood vessels and putting a heavier workload on the heart as it pumps oxygenated blood to the entire body.
Olive oil And Hypertension : Clinical Trials
From a chronological perspective, one of the earliest randomized clinical studies assessing the antihypertensive effect of olive oil dates back to the late 1980s. Here, the antihypertensive effect of a high-fat diet enriched in olive oil was compared to that of a reference diet, low in fat and rich in carbohydrate in a sample of 47 healthy subjects. After 36 days, systolic blood pressure (SBP) and diastolic (DBP) were significantly reduced in both experimental arms, with no significant difference between tested diets, thus suggesting, for the first time, a chance of regulating blood pressure (BP) by manipulating the amount of dietary olive oil. Some years later, these results were confirmed in a group of 15 type-2 diabetic subjects, in which even more powerful antihypertensive effects by a diet enriched in olive oil as compared with a high-carbohydrate diet were observed.
How Does Extra Virgin Olive Oil Aid Blood Pressure
One of the specific compounds in Extra Virgin Olive Oil that directly combats this build-up is called oleuropein. Oleuropein has been found by scientists to prevent the LDL cholesterol from oxidizing and sticking to the arterial walls.
Oleuropein is a natural phenolic compound found in olive leaves and green olives, including the olive’s skin and flesh, from which olive oil is transferred. It causes the bitter taste in Extra Virgin olive oil.
Health Benefits of Oleuropein
Oleuropein health benefits include anti-oxidant and natural anti-inflammatory activity, low blood glucose values and free radicals removal. In addition, oleuropein has been linked to cardioprotective and neuroprotective activity.
Oleuropein belongs to a group of coumarin derivative called secoiridoids. It was found to be effective against various strains of bacteria, viruses, fungi and also moulds or even parasites. Oral treatment with oleuropein results in a decreased number of blood vessels proving strong anti-angiogenic properties. Phenolic compounds (oleuropein, protocatechuic acid) in extra virgin olive oil have also been shown to inhibit macrophage-mediated LDL oxidation. Leaf and olive fruit extracts containing oleuropein protect insulin-producing β-cell line (INS-1) against the deleterious effect of cytokines.
Saturated fat diets are associated with higher blood pressure but there have been few good studies on whether the reverse is true; can unsaturated fats lower bp and are some unsaturated fats better than others?
A well-designed study published by researchers from the University of Naples, Italy fed 23 subjects a diet rich either in monounsaturated fatty acids (MUFA) such as are found in high quality Extra Virgin Olive Oil or polyunsaturated fatty acids (PUFA) such as are found in sunflower oil for one year.
At 26.6% of calories from fat the experimental diet was also low in total fat. The study was double blinded with neither subjects nor researchers aware of which oil was being used. Subjects were told to cook with given oil and men were told to add 40g and women to add 30g of oil after cooking. The study participants experienced no change in weight during the year.
In their words, “the main result of our investigation was a straightforward reduction in antihypertensive tablet consumption when patients were given Extra Virgin Olive Oil, whereas drug consumption was only mildly affected by sunflower oil.”
The need for common bp drugs such as atenolol, HCTZ, and nifedipine was cut in half after just 4 months on the olive oil diet whereas drug consumption was only mildly affected by sunflower oil. Cholesterol and triglyceride levels were also slightly lower while on the olive oil diet. There are as many as 5 mg of antioxidant polyphenols (absent in sunflower oil) in every 10 grams of olive oil. Antioxidants also reduce nitric acid levels, a substance in the body known to raise blood pressure.
Readers with concerns over high blood pressure should consult their doctor.