Plant-based oils have gotten an increasingly bad reputation in recent years, with some health professionals and diet book authors claiming that all vegetable oils are unhealthy and promote inflammation. However, the science shows that not all plant oils are created equal. Many offer proven and substantial health benefits when consumed in moderation as part of an overall healthy diet.
Extra Virgin Olive Oil: A True Superfood Oil
Extra virgin olive oil, a staple of the traditional Mediterranean diet, contains a unique mix of monounsaturated fats, powerful polyphenol antioxidants, and anti-inflammatory compounds. Numerous large and robust human studies have linked higher olive oil consumption to lower risk of cardiovascular disease, including a recent meta-analysis of 32 studies finding those eating the most olive oil had a 15% lower risk of developing cardiovascular disease compared to those consuming the least.
The PREDIMED study, one of the longest and largest randomized trials ever conducted on olive oil and heart health, followed over 7,000 older Spanish adults with high cardiovascular risk for 5 years. Those assigned to consume about 4 tablespoons of extra virgin olive oil daily, in addition to a Mediterranean diet, had a 30% lower rate of major cardiovascular events compared to a control group advised to follow a low-fat diet.
The Cardioprotective effects of olive oil are wide-ranging:
- Olive oil’s monounsaturated oleic acid lowers oxidation of LDL cholesterol particles that can otherwise lead to atherosclerotic plaque buildup in arteries.
- Olive oil provides a bounty of polyphenol antioxidants like oleuropein that protect LDL cholesterol from oxidative damage.
- Consuming olive oil raises levels of HDL “good” cholesterol.
- The polyphenols in olive oil combat inflammation, a key driver of cardiovascular disease, by reducing inflammatory markers like C-reactive protein (CRP).
- Olive oil helps significantly reduce levels of triglycerides, a major independent risk factor for cardiovascular disease. The higher the triglycerides, the greater the benefits.
Some critics argue olive oil must be unhealthy due to its relatively low smoke point and propensity to oxidize at high temperatures. However, extensive research shows extra virgin olive oil is one of the most stable cooking oils, resisting oxidation remarkably well even when heated. One study found it took 24-27 hours of continuous deep frying at 374°F for olive oil to accumulate significant oxidative compounds. By contrast, the polyunsaturated vegetable oils promoted by many low-fat diets oxidized after just 6-9 hours at the same temperature. The notion that olive oil is highly unstable or unsuitable for cooking is not supported by science.
Canola Oil: An Omega-3 Powerhouse
Cold-pressed organic canola oil is another plant oil commonly maligned by diet faddists but offering tangible benefits. While some conventional canola oils may use genetically modified crops or chemical processing, organic canola oil is perfectly healthy. In fact, adding canola oil in place of saturated fats was a major factor in reducing heart attacks and mortality in the landmark Lyon Diet Heart Study.
Participants in this randomized controlled trial all had a previous heart attack. The group eating a Mediterranean diet supplemented with canola oil based salad dressing saw their rates of repeat heart attacks plummet by over 60% and cardiac death rates drop by 70% within 27 months. These dramatic benefits resulted largely from canola oil’s high alpha-linolenic acid (ALA) content.
ALA is an anti-inflammatory omega-3 fatty acid that studies confirm reduces cardiovascular disease risk. A meta-analysis of 27 clinical trials determined ALA-rich diets lower risk of cardiac death by 10% and overall coronary heart disease death by 9%. Canola oil delivers more ALA than any other oil – nearly 10 grams per 2 tablespoon serving. Replacing butter and other saturated fats with canola oil enables substantially boosting protective ALA intake.
The Healthiest Omega-6 Oils
Omega-6 polyunsaturated oils are another category of vegetable oils commonly vilified as promoting inflammation. However, some omega-6 oils offer health benefits and are far preferable to the highly processed industrial oils pervading much of the Western diet. The key is choosing whole food sources of omega-6s in proper balance with omega-3s.
Recent research found supplementing the diet with cold-pressed, unrefined sesame oil substantially lowered blood pressure in hypertensive patients. Another study confirmed incorporating roasted sesame oil in the diet reduces oxidative stress. Sesame oil delivers an antioxidant compound called sesamol that combats inflammation.
Cold-pressed sunflower and safflower oils provide healthier omega-6 alternatives to pro-inflammatory oils like corn, cottonseed, and soybean oils. Sunflower oil is rich in antioxidant vitamin E. High oleic safflower oil is over 75% monounsaturated fat, making it neutral like olive oil.
Avoiding Pro-Inflammatory Industrial Oils
While some plant oils promote wellness, many ubiquitous industrial oils common in processed foods wreak havoc. Heavily refined oils like soybean, corn, cottonseed, and canola oils are high in pro-inflammatory omega-6 fatty acids, especially linoleic acid. They often use chemical solvent extraction and high heat processing that damages delicate polyunsaturated fats.
These oils are incorporated into everything from packaged cakes, cookies, crackers, muffins, cereals, and breads to frozen pizzas, French fries, and nachos. A diet laden with these oils skews omega-6 intake way beyond optimal ratios with omega-3s, creating a perfect recipe for systemic inflammation and chronic illnesses.
Additionally, when used in restaurant deep frying, industrial oils like soybean oxidize into toxic aldehydes and lipid peroxides shown to promote atherosclerosis, neurological damage, liver disease and cancer growth.
The healthiest diet minimizes these oils, instead emphasizing extra virgin olive oil along with omega-3 rich oils like flaxseed. Avocado, almond, walnut and hazelnut oils also make healthy choices for salads and dips. With the right oils in the mix, we can obtain vital nutrients and flavors that keep us satisfied and well.
In conclusion, the notion that all plant oils are equally unhealthy does not stand up to rigorous scientific inquiry. When chosen wisely and incorporated in moderation as part of a wholesome diet, high quality first-pressed oils like extra virgin olive provide a bonanza of essential fats, antioxidants, and anti-inflammatory compounds vital for optimal health. Yet many common industrial oils in processed foods fuel inflammation and chronic disease. Not all oils are created equal – being mindful of what we choose can make all the difference.
