Olives are grown widely in the geographical region surrounding the Mediterranean Sea, and olive oil was a major source of calories in the traditional dietary patterns of that region, now known collectively as the Mediterranean diet.1 Populations that followed this style of eating had reduced rates of death from coronary heart disease and certain cancers.2 Although these health benefits are often attributed to olive oil alone, it is the overall dietary pattern that was health-promoting—the prevalence of unrefined plant foods like vegetables, fruits, nuts, beans, and grains and very limited amounts of animal foods.1 Unrefined plant foods, rather than olive oil, provided the bulk of the omega-3 fatty acids, antioxidants, phytochemicals and minerals in the Mediterranean diet.
Olive oil is not a whole food—it is a fattening, low-nutrient, processed food, consisting of 100% fat. One tablespoon of olive oil has 120 calories, as do all oils. One-quarter cup has 500 calories. Healthy salads are definitely a way of life for people who want to lose weight or improve health, but many of the benefits of a salad are lost when the calorie count is increased ten-fold with oil.
When fats are ingested in the form of extracted oils, they are rapidly and efficiently absorbed by the body and immediately converted into body fat. If these fats were instead ingested from whole foods, such as seeds, nuts and avocado, their absorption would be much slower, over hours, not minutes and these fats would be mostly burned for our energy needs and not stored.
In my book, The End of Heart Disease, I discuss the benefits of eating nuts and seeds rather than adding oil to your diet. The fibers, sterols and stanols in the seeds and nuts would bind some of the fat in the digestive tract, like a sponge, limiting the amount of fat absorbed by the body; adding nuts and seeds to the diet, despite their calorie density, promotes weight loss and healthy weight maintenance, not weight gain.3 Plus, we can consume significantly fewer calories and get a much higher micronutrient value from nuts and seeds compared to olive oil—nuts contain about 40-50 calories per tablespoon, compared to olive oil’s 120 calories.
Olive oil has been associated with cardiovascular benefit in some studies, however the results have been mixed. A 2014 meta-analysis evaluating observational studies of olive oil consumption reported that olive oil consumption was associated with a decreased risk of stroke but not coronary heart disease.4
Olive oil polyphenols (like the polyphenols from berries and other plant foods) have antioxidant and anti-inflammatory activity.5 Also, because olive oil is rich in monounsaturated fats, using olive oil in place of animal fat or other oils higher in saturated fat reduces total and LDL cholesterol.6-8 When olive oil is substituted for animal fats, there is a reduction in risk because you are replacing a more dangerous fat with a less dangerous fat. Olive oil is a better choice than animal products or other vegetable oils, however nuts and seeds are a better choice than olive oil.
Olive oil and nuts were tested side by side in the recent PREDIMED study, which compared three diets: a control low-fat diet, a Mediterranean diet supplemented with olive oil and a Mediterranean diet supplemented with mixed nuts. Both Mediterranean diets reduced blood pressure, fasting glucose levels and total cholesterol after one year.9 After about 5 years of follow-up, both Mediterranean diets provided substantial protection against cardiovascular events compared to the low-fat diet.10 However, when participants were further grouped based on their baseline nut consumption, an important difference emerged. The participants with the lowest risk of death were those that ate three or more servings of nuts a week regularly, and then were assigned to the Mediterranean diet plus nuts group. This study suggests that nuts have a stronger longevity-promoting effect than olive oil.11
Nuts and seeds, are associated with reduced cholesterol levels and dramatic protection against coronary heart disease and sudden cardiac death.12-14 Since fats help you absorb the nutrients in vegetables, replacing the olive oil on your salad with nuts and seeds reduces cardiovascular risk and calories absorbed while providing the maximum nutrient value from the salad.15 In addition to increasing the absorption of nutrients in vegetables, nuts and seeds supply their own spectrum of micronutrients including plant sterols, minerals, and antioxidants. Plus several seeds and nuts (flax, hemp, chia, walnuts) are rich in omega-3 fatty acids, beneficial for heart and brain health.16,17 Some seeds—flax, chia and sesame in particular—are rich in lignans, plant estrogens that protect against breast cancer.18 Nuts and seeds also promote a healthy weight and protect against diabetes.3,19-20Replacing olive oil-based dressings with vinegar, fruit and nut-based dressings are definitely the way to go. Nuts and seeds, not oil, have shown dramatic protection against heart disease. We need to get more of our fats from these wholesome foods and less from processed oils.