We all know that olive oil sprinkled on our salads is good for us, but the full extent of the benefits that this oil confers on our health is truly astounding. As well as being protective against developing heart disease, recent research suggests that regular olive oil consumption also protects against a multitude of diseases and ailments including high blood pressure (hypertension), diabetes, arthritis, weight gain, cancers, and neurological disease.
Olive oil abounds in nutrients responsible for these protective effects all of which are retained after the first cold extraction from the olives (labeled as extra virgin olive oil); Vitamins A, B-1, B-2, C, D, E and K; Iron; and numerous anti-oxidants such as polyphenols. Furthermore, 75% of olive oil is made up of the “good fats , monounsaturated fatty acids (MUFA) which reduce low density lipoprotein levels (LDL-the “bad cholesterol ) and increase high density lipoprotein levels (HDL – the “good cholesterol) in the body.
Numerous population studies have found that people who regularly consume olive oil have markedly lower chances of developing heart disease. One study went so far as to show that a person’s risk of having a fatal heart attack is halved in 2-4 years once they switch to the Mediterranean Diet, which includes using olive oil as the main dietary fat, increasing vegetable intake, and limiting meat and dairy foods.
Several studies have also found olive oil to reduce hypertension and a recent study published in 2000 found that patients who regularly consumed olive oil reduced their amount of antihypertensive medication by 48%, with some of these patients requiring no antihypertensive medication at all. Polyphenols in olive oil are thought to play a role in hypertension by helping to dilate arteries. Further studies relating to heart disease have found that olive oil also protects against thrombosis (blood clots) and platelet aggregation (which can lead to atherosclerosis or blocking of arteries).
Olive oil has been found to have profound protective effects against developing different types of cancers; Population studies measuring cancer rates in countries like Greece, Italy and Spain, where olive oil is used in most households, found cancer incidence to be much lower than that in northern Europe and the United States, where olive oil use is less widespread. A recent study published in 2007 that measured the levels of cancer precursors in urine samples from volunteers in five different European countries, pre- and post-olive oil consumption (25 milliliters every day for three weeks), found that these substances were greatly reduced post-olive oil consumption. Northern Europeans had a high rate of these cancer precursors to start with but these were substantially reduced by the end of the trial.
Although somewhat controversial, olive oil is also thought to reduce the risk of developing breast cancer. Women who follow a Mediterranean-style diet appear to have a lower risk of breast cancer and a recent study has shown that oleic acid, the principal monounsaturated fat in olive oil, dramatically decreased the growth of aggressive forms of breast tumors in test tubes. Furthermore, a combination of oleic acid with the commonly used breast cancer drug Herceptin, vastly increased the effectiveness of the drug. Population studies have further shown that breast cancer is inversely related to the amount of oleic acid consumed.
Laboratory and population studies have also found olive oil to protect against colon cancer. Possible mechanisms include the antioxidant’s effect against cell damage, MUFA’s influence on gut metabolism, and its ability to reduce bile production. MUFU further protects against gastritis and ulcers, and helps to lower the incidence of gallstone formation.
Olive oil’s role in protection from different types of cancer is ongoing; In 2007, a study carried out in the US reported that a pill based on olive oil was able to decrease a man’s chances of developing prostrate cancer by almost 80%. Other recent studies have suggested that olive oil can protect against skin cancer when applied after sun exposure.
Inflammatory diseases such as rheumatoid arthritis have also been shown to be reduced with regular olive oil consumption and a recent study found that Olecanthal, an anti-inflammatory substance in olive oil, was capable of acting like ibuprofen (50 grams or nearly a quarter cup of olive oil provide the same anti-inflammatory action as 10 percent of the standard adult dose of ibuprofen).
Diabetics are also protected by regular olive oil consumption which reduces blood glucose levels, and have even been found to fair better on a diet high in monounsaturated fat than a low-fat, low-carbohydrate diet.
Although olive oil contains 120 calories per tablespoon, studies have shown that people who substituted monounsaturated fat-rich olive oil for saturated fat, either maintained their weight or lost weight and a diet high in monounsaturated fat and low in carbohydrates actually resulted in more weight loss than a low-fat, high-carbohydrate diet.
Other benefits of olive oil include strengthening the immune system and protecting against deterioration of the cognitive functions related to ageing and age-related memory loss.
Contrary to popular belief, olive oil is the safest oil to use while frying and cooking, as it undergoes a smaller degree of deterioration than other oils. Air, heat, light and age affect its shelf life, so appropriate storage is key as is choosing extra virgin olive oil, as virgin olive oil, extra light, and light olive oil denote further processing. According to the studies cited above, anything from two tablespoons to just under a quarter a cup of extra virgin olive oil, should help us reap the rewards of this magical oil.
Dr. May El Meleigyholds a Ph.D in Immunology from the London School of Hygiene and Tropical Medicine, as well as an MSc. (Toxicology/pathology) and a B.Sc in pharmacology) from London University. El Meleigy is a freelance medical/health writer and is currently producing Health Education programs for Egyptian TV.
