Protecting Against Heart Disease
Relying only on olive oil may cut your risk of coronary heart disease almost in half, show results from the CARDIO2000 case-control study, published in Clinical Cardiology (Kontogianni MD, Panagiotakos DB, et al.).
Conducted in Greece, and involving 700 men and 148 women with coronary heart disease, and 1078 age- and sex-matched healthy controls, this study looked not only at diet but also at alcohol intake, physical activity and smoking habits. Nutritional habits, including use of oils in daily cooking or preparation of food, was also evaluated.
Even after adjustments were made to account for a variety of other variables -- including body mass index, smoking, physical activity level, educational status, a family history of heart disease, high blood pressure, high cholesterol and diabetes -- exclusive use of olive oil was associated with a 47% lower likelihood of having coronary heart disease.
Consuming other fats or oils as well as olive oil, however, conferred no protection.
The researchers concluded, "Exclusive use of olive oil during food preparation seems to offer significant protection against coronary heart disease, irrespective of various clinical, lifestyle and other characteristics of the participants."
-Instead of serving butter, fill a small condiment dish with extra virgin olive oil for use on bread, rolls, potatoes or other vegetables.
-For even more flavor, try adding a few drops of balsamic vinegar or a sprinkling of your favorite spices to the olive oil.
-To get the most health benefit and flavor from your olive oil, buy and store oil in opaque containers, and add olive oil to foods immediately after cooking.
Studies on olive oil and atherosclerosis reveal that particles of LDL cholesterol (the potentially harmful cholesterol) that contain the monounsaturated fats of olive oil are less likely to become oxidized. Since only oxidized cholesterol sticks to artery walls, eventually forming the plaques that can lead to a heart attack or stroke, preventing the oxidation of cholesterol is a good way to help prevent atherosclerosis. A recent in vitro study also showed that polyphenolic compounds present in olive oil, including oleuropein, inhibit the adhesion of monocyte cells to the blood vessel lining, a process that is involved in the development of atherosclerosis. In addition, when people with high cholesterol levels removed the saturated fat from their diets and replaced it with olive oil, their total cholesterol levels dropped an average of 13.4%, and their LDL cholesterol levels dropped by 18%. Note, however, that these benefits occured when they used olive oil in place of other fats, rather than simply adding olive oil to a diet high in unhealthy fats.
A study published in the Medical Science Monitor reported that 2 tablespoons a day of olive oil added to an otherwise unchanged diet in 28 outpatients, ranging in age from 64 to 71, resulted in significant drops in total- and LDL cholesterol. Mean concentrations of total cholesterol were lowered by 0.818 mmol/L, and mean concentrations of LDL dropped 0.782 mmol/L. Plus, subjects ratio of HDL:LDL greatly improved; they ended up with higher amounts of protective HDL in relation to lower amounts of dangerous LDL cholesterol.
Three other recent studies (Valavanidis et al.; Morella et al.; Masella et al., see references below) suggest that such heart-healthy effects from olive oil are due not only to its high content of monounsaturated fats, but also to its hefty concentration of antioxidants, including chlorophyll, carotenoids and the polyphenolic compounds tyrosol, hydrotyrosol and oleuropein-all of which not only have free radical scavenging abilities, but protect the vitamin E (alpha-tocopherol) also found in olive oil.
Greek scientists at the University of Athens reporting their research in the Journal of Agriculture and Food Chemistry believe the synergy of all these beneficial nutrients is what is responsible for olive oil's contribution to the health benefits of the Mediterranean diet, a hypothesis supported by Italian research published in the Journal of Nutrition.
In this study, scientists found that the phenols in olive oil have very potent antioxidant effects. The protective effects exerted by extra virgin olive oil biophenols, namely, protocatechuic acid and oleuropein, against LDL oxidation included:
-completely preventing LDL's oxidation when placed in a medium containing macrophage-like cells (in the arteries, arteriosclerosis begins when macrophages damage LDL, starting the development of foam cells that infiltrate the lining of the artery and begin plaque formation)
-inhibiting the production of two powerful oxidants that would normally have been produced and would have damaged LDL, thus preventing the expected decrease in glutathione, a powerful antioxidant the body produces to disarm oxidants (also called free radicals)
-restoring to normal levels the protective activities of two free radical-disarming enzymes that contain glutathione: glutathione reductase and glutathione peroxidase
-inducing higher than normal production and activity of both of these glutathione-containing enzymes.
Olive Oil Especially Protective in People with High Cholesterol
A variation on the above study also shows that including some extra virgin olive oil (which is rich in clot-fighting phenols) in your meals may help prevent the formation of blood clots, an occurrence whose likelihood increases after eating, particularly in people with high cholesterol. In the early stages of atherosclerosis, the balance between clot-promoting and clot-dissolving factors in the blood vessels shifts in favor of clot formation, a situation made even more dangerous by the high levels of fat that can appear in the blood after a meal.
Researchers had 21 people with high cholesterol eat two different breakfasts. For one week, they consumed either white bread with virgin olive oil containing 400 parts per million phenols, or white bread with olive oil from which much of the phenols had been extracted, leaving only 80 parts per million. Study participants then switched to the opposite meal. After the high-phenol olive oil meal, participants' concentrations of two clot promoters, factor VII antigen and plasminogen activator inhibitor-1, were much lower compared to the low-phenol olive oil meal. (Ruano J, Lopez-Miranda J, et al., Am J Clin Nutr.)
Olive Oil Cardio-Protective - But Don't Overdo It
It's the Mediterranean version of the French paradox: in the REGICOR Study, conducted in Spain, researchers found a lower incidence of heart attacks despite a high prevalence of risk factors for cardiovascular disease. Olive oil-which accounts for nearly 35% of calories and is the main source of fat in Mediterranean countries-was a likely explanation.
To investigate this, Maria-Isabel Covas, PhD, Head of The Research Group in Oxidative Stress and Nutrition at the Lipids and Cardiovascular Epidemiology Unit, Institute Municipal du769 Investigacidica, Barcelona, Spain, brought together an international team with partners from Denmark, Finland, Germany and Greece to collaborate in the EUROLIVE Project.
In addition to studies on the bioavailability of polyphenols from olive oil in humans, the EUROLIVE Project has conducted 6 clinical trials in which 3 olive oils, similar except for differences in their polyphenol content (low, 2.7 mg/kg; medium, 164 mg/kg; and high, 366 mg/kg), were given to healthy male volunteers in intervention periods of 3 weeks at doses of 25 mL/day.
Results of the EUROLIVE studies have shown that:
The higher the polyphenolic content of the olive oil, the higher the increase in levels of HDL "good" cholesterol. Average increase in HDL was 0.025 mmol/L for low, 0.032 mmol/L for medium, and 0.045 mmol/L for high phenolic olive oil, respectively. (Extra virgin olive oil contains the most polyphenols, followed by virgin olive oil, olive oil and a highly refined olive oil called "pomace.") Subjects' atherogenic index (their ratio of total cholesterol to HDL cholesterol) and the oxidative (free radical) damage of cholesterol and other lipids decreased as the polyphenolic content of the olive oil increased. (Lipid oxidation--free radical damage to cholesterol and other fats-is considered a high risk factor for coronary heart disease development.
In men from Northern and Central Europe who do not typically eat a Mediterranean diet, daily consumption of 25 mL of olive oil resulted in a 3% decrease in systolic blood pressure. Consuming 25 mL/day of olive oil, in replacement of other fats, did not cause weight gain.
A moderate amount of olive oil-a 25 mL dose (1.7 tablespoons)-did not promote postprandial (after meals) oxidative stress (free radical damage to cholesterol) whereas a single olive oil dose of 40 mL (2.7 tablespoons) did. Practical Tip: Olive oil, particularly extra virgin olive oil, provides a number of heart-healthy benefits-increasing HDL "good" cholesterol, improving the ratio of LDL:HDL, and, if you aren't already following a Mediterranean diet, may lower your systolic blood pressure as well. But don't overdo it. Consuming more than a couple of tablespoons at a meal can increase free radical damage of cholesterol. Key to the Mediterranean Diet's Ability to Reduce Breast Cancer Risk
Olive oil may be the key reason that eating a Mediterranean diet reduces breast cancer risk, suggests a laboratory study published in the Annals of Oncology. Oleic acid, the main monounsaturated fatty acid in olive oil, has been shown to reduce the expression of the Her-2/neu oncogene, which is associated with the aggressive growth of breast cancer tumors. High levels of Her-2/neu are found in one-fifth of breast cancers, especially those that are resistant to treatment.
In this study, when Menendez and his colleagues from Northwestern University in Chicago exposed two strains of aggressive breast cancer cells to oleic acid, levels of Her-2/neu dropped 46%. When they combined oleic acid with lower levels than are normally used of Herceptin, a drug used to treat breast cancer, oleic acid greatly enhanced the effectiveness of the drug, dropping Her-2/neu expression as much as 70%. The end result: oleic acid promoted the apoptotic cell death (suicide) of aggressive, treatment resistant breast cancer cells.
A human study adds to the evidence that olive oil is a key factor in the lowering of breast cancer risk associated with a Mediterranean diet. Results of this two-year long study involving 755 women in the Canary Islands suggest that monounsaturated fat and, specifically, olive oil exert a protective effect against breast cancer.
Study participants consuming the most monounsaturated fat were found to have a 48% lower risk of breast cancer compared to women whose intake of monounsaturated fat was lowest.
Among women consuming the most olive oil, specifically, the risk of breast cancer was even lower. Compared to those consuming the least olive oil, women whose daily intake of olive oil was at least 8.8 grams, the equivalent of just .65 tablespoon/day, had a 73% lower risk of breast cancer risk!