Want to stay up to date in the Olive Oil world? Check out the Olive Oil Times.
THE BENEFITS OF CONSUMING FRESH, EXTRA VIRGIN OLIVE OIL
Extra virgin olive oil is not only a light and delicate addition to many wonderful dishes, it is one of the most health-promoting types of oils available. Olive oil is rich in monounsaturated fat, a type of fat that researchers are discovering has excellent health benefits.
Protection Against Chronic Degenerative Disease
In many parts of the world, a high fat intake is associated with degenerative diseases such as atherosclerosis, diabetes, asthma, colon cancer, and arthritis. But in some parts of the world, a high fat intake is actually associated with lower rates of these conditions. A closer look at the foods eaten in these places reveals that the high fat intake is actually due to the generous use of olive oil. Comparing these areas, such as the Mediterranean, where olive oil is the main fat used, to other regions, like the United States, where other fats such as animal fats, hydrogenated fats and vegetable oils like corn oil dominate, turns up some very interesting data. It turns out that people who use olive oil regularly, especially in place of other fats, have much lower rates of heart disease, atherosclerosis, diabetes, colon cancer, and asthma.
Live Longer ~ Eat an Olive Oil-Rich Mediterranean-style Diet
In a prospective study (one in which participants are chosen and then followed forward in time) involving 5,611 adults 60 years or older, adherence to a Mediterranean style dietary pattern - characterized by high consumption of olive oil, raw vegetables, soups, and poultry - was associated with a significantly lower risk of death from all causes.
After 6.2 years, those most closely following a Mediterranean 'olive oil and salad' dietary pattern had a 50% reduced risk of overall mortality. Much less favorable were the results seen in those most closely following a 'pasta and meat' dietary pattern - characterized by pasta, tomato sauce, red meat, processed meat, added animal fat, white bread and wine - whose overall mortality risk increased.
Study authors concluded, "Dietary recommendations aimed at the Italian elderly population should support a dietary pattern characterized by a high consumption of olive oil, raw vegetables and poultry." (Masala G, Ceroti M, et al., Br J Nutr.)
Heart Health ~ Olive Oil Highly Protective 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."
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 occurred 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:
Olive Oil, Super Food for the Heart
A review of the research by noted olive oil researcher Maria Covas strongly suggests that diets in which olive oil is the main source of fat can be a useful tool against a wide variety of risk factors for cardiovascular disease. (Covas MI, Pharmacology Research)
On November 2004, the Federal Drug Administration (FDA) of the U.S.A permitted a claim on olive oil labels concerning: "the benefits on the risk of coronary heart disease of eating about two tablespoons (23 g) of olive oil daily, due to the monounsaturated fat (MUFA) in olive oil."
But recent studies have shown that olive oil contains much more than MUFA. Olive oil is a functional food that is also rich in antioxidants and phenolic compounds with a variety of protective effects.
The cholesterol of a person whose diet is high in olive oil will primarily contain oleic acid, the fatty acid that predominates in olive oil, and oleic acid is more resistant to free radical or oxidative damage. And not only will the LDL of a person whose dietary fat is primarily olive oil produce LDL that is more resistant to free radical damage, but that individual's LDL will be further protected by olive oil's supplies of vitamin E and phenols with antioxidant activity, further lessening the likelihood of its being oxidized.
By reducing both inflammation and free radical damage to cholesterol, dietary olive oil protects the endothelium, the lining of our blood vessels, helping to maintain its ability to relax and dilate (thus preventing high blood pressure).
By protecting LDL against oxidation, olive oil short circuits the process through which atherosclerotic plaques form. (Only once oxidized does LDL adhere to the endothelium, attracting immune cells (monocytes) that try to clear it out, turn into foam cells and begin plaque formation.)
The anti-inflammatory effects of a virgin olive oil-rich diet also result in a vascular environment in which platelets are less likely to clump together and form blood clots. Not only do olive oil's antioxidant compounds lessen the inflammation initiated by free radical damage, but olive oil is rich in inhibitors of a compound called platelet activating factor (PAF). PAF begins the clotting process by causing platelets to aggregate and is also involved in the activation of immune cells and their binding to the endothelial wall.
Compared to diets high in saturated fat and low fat, high carbohydrate diets, a number of studies have shown that olive oil-rich diets not only reduce LDL cholesterol levels, but also lower blood sugar levels and decrease insulin requirements in persons with type 2 diabetes.
Practical Tip: Rely on delicious, flavorful virgin olive oil as your first choice for dressing salads. Put a little olive oil and balsamic vinegar on your bread plate and use it to add flavor to crusty whole wheat bread and rolls. Drizzle olive oil over potatoes, beans, grains, steamed vegetables, and soups. You will not only enhance the flavor of your food, but greatly reduce your cardiovascular disease risk.
Virgin Olive Oil the Best Oil for Heart Health
Virgin olive oil, a much richer source of polyphenols than refined olive or other refined oils, is the best vegetable oil for heart health, shows the results of the Eurolive study, published in the September 2006 Annals of Internal Medicine.
The 6 research center study, led by Maria-Isabel Covas of the Municipal Institute of Medical Research in Barcelona, assigned 200 healthy men from 5 European countries - Spain, Denmark, Finland, Italy and Germany - to one of three sequences of daily consumption of olive oil.
The men replaced their normal dietary fats with olive oil (25 mL) containing either 2.7 (refined), 164 (virgin), or 366 (extra virgin) mg/kg of phenols for 3 weeks. This was followed by 2 weeks without any olive oil and then a cross-over to each of the other 2 remaining interventions.
Blood samples were taken before and after each intervention to measure blood sugar, total and HDL (good) cholesterol, triglycerides, free radical damage to cholesterol, and antioxidant levels.
The data revealed a linear increase in HDL (good) cholesterol levels as the phenolic content of the olive oil increased, with increases of 0.025, 0.032, and 0.045 mmol/L for the low, medium and high polyphenol-containing olive oils.
Oxidized LDL (the form in which LDL is involved in atherosclerosis) decreased linearly, dropping from 1.21 U/L , to -1.48 U/L , to -3.21 U/L for the low-, medium-, and high-polyphenol olive oil, respectively. And the ratio of total to HDL cholesterol, considered the most specific cholesterol-associated risk factor for cardiovascular disease, also decreased linearly as the phenolic content of the olive oil rose.
"Olive oil is more than a monounsaturated fat. Its phenolic content can also provide benefits for plasma lipid levels and oxidative damage," concluded the researchers.
A statement released by the Municipal Institute of Medical Research noted, 'This study represents a key piece for recommendations and contributes information with great repercussions for the community, especially in populations or countries where olive oil does not comprise the habitual oil of the diet."
Extra virgin olive oil-organic, if available-may cost a bit more than lesser quality oils, but the significant increase in cardiovascular benefits, not to mention richer flavor it provides, make it an extremely good investment in your health.
Key to the Mediterranean Diet's Ability to Lower Blood Pressure
Theodora Psaltopoulou and colleagues from the University of Athens, Greece investigated whether the Mediterranean diet as a whole, or just olive oil, is responsible for the reduction in blood pressure associated with this way of eating. Their finding: while the diet as a whole reduces blood pressure, olive oil, by itself, is largely responsible.
The Greek team examined the ability of the total diet and of olive oil alone to reduce arterial blood pressure. Their study included over 20,000 Greek participants who were free of hypertension (high blood pressure) when the study began. Food frequency questionnaires were completed and systolic and diastolic blood pressures were taken.
Diet was evaluated by a 10 point score that reflected the extent to which study participants followed the Mediterranean diet and also provided scores for individual components of the diet, including olive oil.
Data analysis confirmed that the Mediterranean diet as a whole was significantly associated with lower systolic and diastolic blood pressure as were olive oil, vegetables and fruit. On the other hand, consumption of cereals, meat and meat products, and alcohol intake was associated with higher blood pressure. When the effects of olive oil and vegetables were compared, olive oil was found to be responsible for the dominant beneficial effect on blood pressure.
Polyphenols, not Fats, Responsible for Olive Oil's Benefits
It's likely the abundance of polyphenols in extra virgin olive oil, rather than its monounsaturated fatty acids, are responsible for its well-known cardiovascular benefits.
And its rich supply of polyphenols, which are known to have anti-inflammatory, antioxidant and anticoagulant actions, may also be central to emerging evidence that olive oil's protective effects extend to colon cancer and osteoporosis (see Protection against Colon Cancer, Olive Oil Polyphenols Prevent Bone Loss also in this section).
Research conducted by Dr. Juan Ruano and colleagues at the Reina Sofia University Hospital, Cordoba, Spain, and published in the Journal of the American College of Cardiology, investigated the effects of virgin olive oil on endothelial function in 21 volunteers with high cholesterol levels.
The endothelium, although just a one-cell thick layer of flat cells that lines the inner wall of all blood vessels, may be the critical player in cardiovascular health. Among its many functions, the endothelium orchestrates the mechanics of blood flow, and regulates blood clot formation and the adhesion of immune cells to the blood vessel wall (one of the first steps in the formation of plaque).
Normally, after a meal, endothelial function is impaired for several hours. Blood vessels become less elastic, and blood levels of free radicals potentially harmful to cholesterol (lipoperoxides and 8-epi prostaglandin-F2) rise.
But when the subjects in this study ate a breakfast containing virgin olive oil with its normal high phenolic content (400 ppm), their endothelial function actually improved, blood levels of nitric oxide (a blood vessel-relaxing compound produced by the endothelium) increased significantly, and far fewer free radicals were present than would normally be seen after a meal.
When they ate the same breakfast containing the same type of virgin olive oil with its phenolic content reduced to 80 ppm, the beneficial effects were virtually absent, and concentrations of cholesterol-damaging free radicals increased.
The results of this study underscore the importance of knowing how to select, store and serve your olive oil to maximize its polyphenol content. For all the information you need, see our How to Select and Store section below.
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 d́Investigació Mèdica, 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!
Better Blood Sugar Control
Studies in diabetic patients have shown that healthy meals that contained some olive oil had better effects on blood sugar even than healthy meals that were low in fat. When olive oil is used to enhance a low-saturated fat, high carbohydrate diabetic diet, the diet still has beneficial effects on blood sugar control. In addition to this, a good diabetic diet with some olive oil added helps to keep triglyceride levels low. Triglyceride levels tend to be high in diabetic patients, which is a problem since high levels also contribute to the development of heart disease. So a high carbohydrate, healthy diabetic diet with some olive oil added in can help for several reasons.
Helps Prevent Belly Fat and Improve Insulin Sensitivity
What you eat may affect where fat deposits on your body. Belly fat is associated with insulin resistance, which leads to further weight gain and increases risk of type 2 diabetes.
When researchers fed type 2 diabetic patients different diets - a high carbohydrate diet, or a diet rich in either saturated fat or olive oil (Mediterranean diet) - the high carb diet increased abdominal fat compared to the fat-rich diets. Of the three diets, the diet rich in olive oil did best, preventing not only belly fat accumulation, but the insulin resistance and drop in adiponectin seen after the high carbohydrate diet meals.
Adiponectin, a hormone produced and secreted by fat cells (adipocytes), regulates sugar and fat metabolism, improves insulin sensitivity, and has anti-inflammatory effects on the cells lining the blood vessel walls. Low blood levels of adiponectin are a marker for metabolic syndrome, are common in obesity, and are also associated with increased heart attack risk.
Your diet supplies not just calories but information. The instructions delivered to your cells by a Mediterranean-type diet rich in monounsaturated fat from olive oil and nuts will improve your sensitivity to insulin, lower your blood sugar, and help prevent fat from collecting around your middle. (Paniagua JA, Gallego de la Sacristana A, et al., Diabetes Care)
As far as other diseases go, regular use of olive oil has been associated with lower rates of asthma and rheumatoid arthritis. The monounsaturated fats in olive oil are used by the body to produce substances which are relatively anti-inflammatory. By reducing inflammation, these fats can help reduce the severity of arthritis symptoms, and may be able to prevent or reduce the severity of asthma.
Minor components of extra virgin olive oil-namely, its squalene, beta-sitosterol and tyrosol -may help explain why the Mediterranean diet has shown such beneficial effects on cardiovascular health and cancer prevention, suggests a study published in Free Radical Biology and Medicine.
It is generally accepted in the medical community that excessive production of free radicals and inflammatory compounds derived from the body's use of omega-6 fatty acids (found primarily in meats, corn, safflower and sunflower oils) contributes to the development of both cardiovascular disease and cancer.
In this study, researchers tested the effects of squalene, beta-sitosterol and tyrosol on a number of free radicals as well as on inflammatory compounds produced from omega-6 fats (arachidonic acid metabolites). In each case, the olive oil compounds either significantly inhibited production of the problem-causing molecules or rendered them harmless.
Olive Oil Phenols' Help Prevent Bone Loss
The bone-sparing effects of olive polyphenols revealed in studies conducted by a special team at INRA (France's National Institute for Agricultural Research) are so dramatic that a new Belgian firm, BioActor, has licensed INRA's patents to use olive polyphenols for osteoporosis prevention in food, supplements and herbal medicines.
The World Health Organization calls osteoporosis its biggest global healthcare problem with aging populations also beset by obesity, a condition now known to greatly increase inflammation throughout the body, including in bones where it significantly contributes to osteoporosis. Today, a woman's lifetime risk of osteoporotic fracture is 30-40%, and even men face about a 13% risk.
INRA researchers, inspired by epidemiological evidence that people eating a traditional Mediterranean diet were less likely to develop osteoporosis, began investigating the effects of olive oil and different compounds in olive leaves on bone metabolism.
Their early studies revealed that two olive polyphenols, oleuropin and hydroxytyrosol, greatly lessen the inflammation-mediated bone loss involved in osteoporosis.
Then they published research in the British Journal of Nutrition, showing that both oleuropein and olive-oil feeding can prevent inflammation-induced osteopenia (bone-thinning) in animals whose ovaries have been removed-an animal model designed to simulate senile osteoporosis, the bone-wasting condition that affects the elderly, as it combines both hormone deficiency with chronic inflammation.
Although the animals did not fully recover all their bone density compared to controls, those rats fed oleuropin (0.15g/kg) or olive-oil (50 g/kg) daily for 3 months recovered 70-75% of their bone density-a 50% improvement compared to control animals, which were given 25g/kg peanut oil and 25 g/kg rapeseed oil daily.
The INRA team, led by Dr. Veronique Coxam, is developing the protocol for a human study, which, if all goes well, could be started before the end of 2006.
Olive Oil Phenols Protect DNA from Free Radical Damage
Extra-virgin olive oil, which, when properly cold pressed and stored in opaque containers, is naturally high in phenolic compounds with antioxidant properties, may be one of the key reasons for the lower incidence of cancer and cardiovascular disease in the Mediterranean region, suggests a study published in the British Journal of Nutrition.
This randomized, crossover study involving 10 healthy postmenopausal women in Florence, Italy, found that when the women consumed extra-virgin olive oil high in phenols, their DNA experienced a whopping 30% less damage than that seen when they consumed an olive oil in which the content of phenols, which can be destroyed by light and heat, was low.
Be sure to buy only cold pressed, extra virgin olive oil sold in an opaque container or can to prevent its exposure to light and preserve its phenol content.
Potent Anti-Inflammatory Compound Discovered in Olive Oil
Could olive oil become the new anti-inflammatory standby? Someday soon, your doctor may recommend you prevent aches and pains, and reduce your risk of cancer, by telling you to enjoy extra-virgin olive oil with your meals throughout each day, suggests a study led by Pennsylvania biologist Dr. Gary Beauchamp and published in Nature.
Inspired by a tasting experience at a molecular gastronomy meeting in Sicily, where he noticed that high quality olive oil produced a throat-stinging sensation similar to that caused by ibuprofen, Beauchamp and his team analyzed freshly pressed extra-virgin olive oil and discovered a compound that suppresses the prostaglandin system, the same pain pathway as non-steroidal anti-inflammatory agents, such as ibuprofen.
Although its chemical structure is quite different from the anti-inflammatory compounds in non-steroidal drugs, olive oil's anti-inflammatory component, which Beauchamp named "oleocanthal," has a similar effect.
A 50 gram dose (about 4 tablespoons) of extra-virgin olive oil supplies enough oleocanthal to produce an effect equivalent to that of about 10% of the ibuprofen dose recommended for adult pain relief.
While this amount won't cure a headache (and most people may not have the room in their diet for the calories and fat contained in 4 tablespoons of olive oil), daily consumption of olive oil may prevent inflammation and confer some of the benefits of long-term ibuprofen use-without the increased risk of intestinal bleeding and damage to the kidneys that long-term use of non-steroidal drugs like ibuprofen also carries.
Scientists believe this finding is significant because inflammation plays a key role in a variety of chronic diseases. "Some of the health-related effects of the Mediterranean diet may be due to the activity of oleocanthal from premium olive oils," said Beauchamp. Dr Paul Breslin, who directed the research with Beauchamp, added:
"The Mediterranean diet, of which olive oil is a central component, has long been associated with numerous health benefits, including decreased risk of stroke, heart disease, breast cancer, lung cancer, and some dementias. Now that we know of oleocanthal's anti-inflammatory properties, it seems plausible that oleocanthal plays a causal role in the health benefits associated with diets where olive oil is the principal source of fat."
Although oleocanthal should be present in any extra-virgin olive oil, concentrations will vary depending upon a range of factors, including the variety of olive and the age of the olives at pressing.
The best way to check your olive oil for oleocanthal content? "Sip the oil neat and see how strongly it stings the back of the throat," recommends Breslin. "The greater the sting, the greater the oleocanthal content."
Supports Gastrointestinal Health
While most other fats are associated with an increased risk of colon cancer, olive oil is actually associated with a reduced risk of this disease.
One reason for olive oil's protective effect may be its ability to reduce the amount of carcinogenic heterocyclic amines (HAs) formed when meats are cooked, suggests a study published in Food Chemistry Toxicology. The addition of foods containing antioxidants to recipes containing meat has previously been shown to decrease the amount of HAs produced during cooking. In this study, beefburgers were fried in both virgin and refined olive oils as well as virgin olive oil with rosemary extract and refined olive oil with rosemary extract. Burgers fried in virgin olive oil had significantly less HAs than those cooked in refined olive oil; however, the longer the oil was stored, the less its HA-reducing effect-a good reason to buy olive oil in small quantities that you will use within a month or two. Researchers theorized that adding rosemary to virgin olive oil might help prevent this drop in its protective effects.
The incidence of colon cancer is lower in Mediterranean countries compared with those in northern Europe, a benefit believed to be due to the central role of olive oil in the Mediterranean diet. Laboratory research published in the International Journal of Cancer further supports this hypothesis, showing that phenolic compounds in virgin olive oil protect against several stages of colon cancer development.
To investigate olive oils' protective mechanisms of action, researchers at the University of Ulster in Northern Ireland extracted phenols from virgin olive oil and used them in a series of in vitro (lab test) experiments modeling important stages of colon carcinogenesis.
In one cell culture experiment, colon cells incubated with olive phenols for 24 hours were protected from hydrogen peroxide-induced DNA damage. The higher the level of olive oil phenols, the better the protection.
In a second cell culture, at 48 hours, olive phenols at a concentration of 50 μg/ml or more had significantly improved the barrier function of colon epithelial cells (the cells that form the lining of the colon), suggesting that the phenols might be exert an anti-promoter effect in the carcinogenesis pathway.
A third cell culture showed significant inhibition of HT115, a highly invasive human colorectal cancer cell line, at phenol concentrations of 25, 50, 75 and 100 μg/ml, indicating that olive oil phenols might also reduce the invasiveness of colon cancer cells.
Helicobacter pylori, a bacteria that burrows into the gastric lining causing chronic inflammation and promoting the development of peptic ulcers and gastric cancer, is becoming increasingly resistant to antibiotics.
The search is on for other substances able to fight H.pylori with researchers increasingly turning not only to herbal extracts and essential oils used in traditional medicines, but to polyphenol-rich foods.
Virgin olive oil, one of the few edible oils that is consumed unrefined, contains a number of active phytonutrients. Having run experiments on food-borne pathogens that showed olive oil polyphenols have a very high level of antimicrobial activity against food-borne pathogens, Concepcion Romero and her colleagues at the University Hospital of Valme, Seville, Spain, decided to in investigate olive oil's effects on H.pylori.
Using conditions that simulated the human gastric environment, Dr. Romero and her team demonstrated that a significant amount of the polyphenols in the olive oil diffused from the oil into the stomach acid and remained stable for several hours, exerting strong anti-H.pylori activity, even against some strains resistant to antibiotics.
Also, only very low concentrations of the olive oil extracts were necessary. Among the polyphenols showing anti-H.pylori activity, one named Ty-EDA was so effective that only <1.5 μg/mL of this compound was needed to kill H.pylori cells in test tube experiments. To put this in practical perspective, Ty-EDA is present in most virgin olive oils in concentrations up to 240 μg/mL.
While these results need confirmation in human studies, they are quite promising, especially given earlier Russian research involving olive oil and gastric ulcer. In this study, when patients with gastric and duodenal ulcers replaced the animal fat in their diet with olive oil, ulcer size was greatly reduced and the percentage of ulcer healing significantly increased. (Taits NS, cited in de la Lastra A, et al.,Current Pharmaceutical Design).
Practical Tip: Promote your gastrointestinal health by replacing the butter and refined oils in your diet with extra virgin olive oil. Since the phenols and vitamin E in olive oil are damaged by light and heat, purchase and store your olive oil in an opaque container. And don't use olive oil for cooking. Steam or lightly sauté foods in a flavorful broth, then dress with olive oil immediately after cooking. You'll get more flavor and more nutrients from your oil.
A Fat That Can Help You Lose Fat
Substituting olive oil, a monounsaturated fat or MUFA, for saturated fat in your diet can translate into a small but significant loss of both body weight and fat mass without changing anything else about your diet or increasing your physical activity, suggests a study published in the British Journal of Nutrition. One of the most interesting facts about this research is that it was conducted on eight overweight or obese men, ranging in age from 24 to 49 years. All the men followed one of two diets for 4 weeks each. The first, saturated fat-rich diet provided 24% of calories from saturated fat, 13% from monounsaturated fat, and 3% from polyunsaturated fat, while in the second MUFA-rich diet, 11% of calories came from saturated fats, 22% from monounsaturated fat and 7% from polyunsaturated fat. At the end of the MUFA-rich diet, despite the fact that no significant differences were detected in caloric intake, energy expenditure or physical activity, the men were 2.1 kg lighter and their fat mass had decreased by 2.6 kg.
Additional support for olive oil's fat burning effects comes from another study published in the British Journal of Nutrition, which suggests that the monounsaturated fats found in olive oil cause an increase in the breakdown of fats in fat cells (adipocytes). In this study, 45 laboratory animals were divided into three groups, each of which was fed a diet supplying normal energy but a different type of fat: olive oil, palmitic acid or soybean oil + palmitic acid. At the end of the study, a number of indicators of fat metabolism were measured including body weight, plasma leptin, tissue concentration of fatty acids, fat-cell size, fat cell lipolytic (fat breakdown) activity, and the capacity of insulin to inhibit fat breakdown. In the animals receiving monounsaturated fats, not only was fat breakdown greater, but insulin's ability to block it was lower. Interestingly, in rats given polyunsaturated fat in the form of soybean oil, the opposite effect was noted in adipose (fat) tissue.
Extra virgin olive oil is definitely one of the best food oils available today. Simply adding olive oil to an unhealthy diet that is already soaked in saturated fats or vegetable oils will not lead to any of the benefits listed above and may actually cause more harm than good, but when pure, extra virgin olive oil is used as a primary source of fat in a whole foods, healthy eating plan, the potential goodness of this oil prevails.