Eating more olive oil predicts better cardiovascular health, lower mortality risk
Aim for extra-virgin olive oil
Olive oil is a key component of the Mediterranean diet. Observational studies and one randomized trial (the Lyon Diet Heart Study) suggest that a Mediterranean-style diet reduces the risk of cardiovascular disease. A more recent randomized controlled trial (PREDIMED) in Spain provides additional evidence of the health benefit of a Mediterranean diet. Participants included men and women (age 55 to 85) with no cardiovascular disease at baseline but with major cardiovascular disease risk factors (either type 2 diabetes or any three of smoking, hypertension, elevated LDL cholesterol, reduced HDL cholesterol, overweight or obese, or a family history of premature coronary heart disease). A total of 7,447 people were randomized into one of three groups: Mediterranean diet plus extra-virgin olive oil, Mediterranean diet plus nuts, or a control diet (advised to reduce fat intake). The average follow-up period was 4.8 years when the trial was stopped because the data were so compelling.
Based on statistical models that controlled for many confounding factors, subjects in the Mediterranean diet plus olive oil and in the Mediterranean diet plus nuts groups had significant 31 and 28 percent lower risks, respectively, of a major cardiovascular event (heart attack, stroke, or death from cardiovascular causes) compared to subjects in the control diet group during follow-up. The researchers attributed the health benefits of the Mediterranean diet mostly to extra-virgin olive oil and nut consumption. In addition, the baseline diet of most participants was similar to the Mediterranean diet, suggesting that the health advantage of a Mediterranean diet would be even greater compared to the standard American diet.
Studies suggest that diets rich in olive oil may reduce the risk of cardiovascular disease. Olive oil contains mostly mono-unsaturated fats that are relatively immune to oxidation during cooking. Olive oil also contains phytonutrients and has anti-inflammatory properties. Might the beneficial effects of the Mediterranean diet arise from eating lots of olive oil? Researchers used data from 7,216 participants the PREDIMED study to find out. Compared to participants in the lowest one-third of total or extra-virgin olive oil intake (21 grams or 2 tablespoons per day), those in the highest one-third (59 grams or 6 tablespoons per day) of intake had significant 35 and 39 percent reduced risks, respectively, of a major cardiovascular event during follow-up and after adjusting for confounding factors. Each 10 gram per day increase in extra-virgin olive oil intake predicted a 13 percent lower risk of a major cardiovascular event. Thus, olive oil, especially extra-virgin olive oil, may account, at least in part, for the cardiovascular benefits of a Mediterranean diet.
Many Spanish residents eat a Mediterranean diet with lots of olive oil. The PREDIMED study showed that older Spaniards lowered their risk of major cardiovascular events as their intake of olive oil increased. Would Americans who eat olive oil (but less than that of Spaniards) enjoy similar benefits? Researchers at Harvard used data from 61,181 women in the Nurses’ Health Study and 31,797 men in the Health Professionals Study to find an answer. After adjusting for a host of confounding factors and compared with participants with no or minimal intake of olive oil, participants in the highest quartile of olive oil intake (more than one-half tablespoon per day) had significant 14 and 18 percent lower risk, respectively, of developing cardiovascular disease or coronary heart disease during 24 years of follow-up. Replacing 5 grams per day of margarine, butter, mayonnaise, or dairy fat with the equivalent amount of olive oil predicted a significant 5-7 percent lower risk of cardiovascular disease or coronary heart disease. In addition, higher olive oil intake predicted lower levels of several inflammatory biomarkers. Even the modest amount of olive oil consumed by most Americans predicts better cardiovascular health.
Olive oil enjoys a large measure of respect from health-conscious Americans. Do Americans who consume lots of olive oil live longer than those who don’t? Researchers at Harvard and in Spain used data from the 60,582 women participants in Nurses’ Health Study and 31,801 men participants in the Health Professionals Follow-up Study. Food intake data were collected every four years over 28 years of follow-up. Olive oil intake was classified as 1) less than 1 gram per month, 2) from 0.1 to 1.5 teaspoons per day, 3) from 1 to 1.5 teaspoons per day, and 4) equal to or more than 0.5 tablespoons per day.
Compared to participants in the lowest quartile of olive oil intake, those in the highest quartile had significant 19 percent lower risk of dying from any cause during follow-up. Comparable significant reductions in risk of dying from cardiovascular disease, cancer, neurodegenerative disease, or respiratory disease were 19, 17, 29, and 18 percent, respectively. In addition, each 5 gram (about 1/2 tablespoon) increase in olive oil intake predicted significant reductions in risk of each of the above causes of mortality. Finally, substituting 10 grams per day of olive oil for 10 grams of margarine, butter, mayonnaise, or dairy fat predicted significant 8-34 percent lower risks of all-cause mortality, respectively. These results reflected adjustment for many confounding factors including diet. Olive oil may exert its evident health effects via anti-inflammatory and anti-atherogenic (artery plugging) effects and by improved blood fat profiles, insulin sensitivity, and blood sugar control. Shift your fat intake to olive oil and you may live longer.