Is canola oil heart healthy?

I was cooking the other day in a kitchen that isn’t my own, and I came across a bottle of canola oil. I was super fascinated to see that it had a large “Heart Healthy” label on it, followed by the statement that “Canola oil is a cholesterol free food with 14 g of total fat per serving.” That got me totally curious about the requirements for something to be labeled as heart healthy. Let’s recap the latest science on canola oil and how it got it’s heart healthy label. Is canola oil actually good for your heart?

What is canola oil?

Canola oil is a vegetable-based oil. It’s made from a derivative of the rapeseed plant, and is very commonly found in many processed and packaged foods. In fact, second only to soybean oil, it is the most commonly consumed oil in the United States. Chemicals are used to process and extract the oil at high heat. Because it is refined, it is fairly devoid of nutrients other than some vitamin E and K. It has a very high smoke point (468 degrees F), which makes it ideal for high heat cooking.

Although it varies somewhat from brand to brand, canola oil is mostly monounsaturated fat (~61-68%), with minimal saturated fat (~7%) and trace to minimal trans fat. Of note, this is less saturated fat than is found in olive oil!

The remainder of the fatty acids come from polyunsaturated fats (PUFAs), with about a 2:1 ratio of omega-6 fatty acid (from linoleic acid) to omega-3 (from alpha-linolenic acid aka ALA).

There are also trace plant sterols, which can lower cholesterol when consumed in large quantities.

What are the possible health benefits of canola oil?

As mentioned, canola oil is quite low in saturated fat. In fact, it is lower in saturated fat than any other oil. Given that we know that saturated fat raises LDL cholesterol, canola oil would appear to be a safe heart health bet to replace products high in saturated fat, like butter.

As such, it is not surprising that a 2013 review (which, btw, was funded by the Canola Council of Canada and US Canola Association) found that replacing saturated fats with canola oil decreased total cholesterol and LDL cholesterol. However, the results of studies comparing canola oil with other vegetable oils are less consistent. It was also found to improve insulin sensitivity, but had inconclusive effects on inflammation, LDL oxidation, energy metabolism, and clotting.

Importantly, we do not have any long-term interventional or observational studies to show that canola oil has benefits on cardiovascular health outcomes.

What are the concerns with canola oil?

Given that it is highly refined - including bleaching and deodorizing - many of the vitamins and antioxidants are removed. This is in contrast to unrefined oils, such as extra virgin olive oil, in which many of these healthful nutrients are left intact.

Secondly, it remains a significant source of omega-6 fatty acids. As I covered here, while omega-6 fatty acids are essential for our bodies, there is currently a major imbalance in the Standard American diet, consuming much more omega-6 than omega-3. While the exact optimal omega-6 to omega-3 ratio isn’t known, high omega-6 consumption has been linked to inflammation, obesity, and heart disease. As such, with the best available current evidence, it makes sense to reduce our intake of omega-6 when possible. Although canola oil’s omega 6 to omega 3 ratio is fairly respectable at 2:1, given that it is found in many processed and packaged foods, it remains a significant source of omega 6 in the Standard American diet. Of note, soybean oil, sunflower oil, and corn oil are higher in omega-6 polyunsaturated fatty acids (PUFAs) than canola oil.

In addition, there is some concern that the heating during manufacturing as well as high heat cooking (like frying) can negatively impact the the fragile omega-3 (ALA), resulting in oxidized compounds. The normally protective antioxidants are virtually (if not completely) removed in canola oil.

How does it compare to olive oil?

Compared to olive oil, canola oil has quite a favorable lipid profile - it has a similar amount of monounsaturated fat, a lower amount of saturated fat, and more omega-3 polyunsaturated fatty acid.

However, extra virgin olive oil is produced at low temperatures, which retains its polyphenol content and other components that may reduce inflammation and oxidative stress. Canola oil is mostly devoid of antioxidants and polyphenols. Some studies suggest that the beneficial effect of extra virgin olive oil may be due in part to these polyphenols and associated antioxidant activity, not just in fatty acid composition.

And, unlike olive oil, we have NO long term studies demonstrating any heart health benefit of canola oil. Olive oil, on the other hand, has been clearly demonstrated to reduce cardiovascular events.

How did canola oil gets it claim for heart health?

Due to its unsaturated fat content, in 2006, the FDA authorized a qualified health claim petitioned for by the US Canola Association for canola oil's ability to reduce the risk of heart disease when used in place of saturated fat. It states:

"Canola oil (19 grams – about 1 ½ tablespoons per day) may reduce the risk of coronary heart disease due to its unsaturated fat content, according to supportive but not conclusive research. Canola oil should replace a similar amount of saturated fat in the diet without increasing calories."

According to the American Heart Association, for a product to be certified under it’s Heart-Check Food Certification Program, it must meet specific nutrition requirements. For liquid oils, and canola oil in particular, it must have 1 gm or less saturated fat (and 15% or less calories from saturated fat), 0.5 g or less trans fat, 20 mg or less cholesterol, and 0 mg sodium.

That’s it.

Thus, the heart healthy claims and labeling for canola oil is based on theoretical reductions in cardiovascular disease based on biomarker studies, not on actual outcome trials.

So, is canola oil heart healthy?

Remarkably, we don’t know.

Here’s what we do know. Canola oil, which is high in MUFA and to a certain extent, PUFAs, lowers cholesterol and improves insulin sensitivity when it replaces saturated fat. Based on what we know about saturated fat (and the animal products from which they typically come), this is not all that surprising. But given the other concerns listed above, most importantly that we have no outcome data that support’s the claim that it reduces cardiovascular disease, I would not call it “heart healthy.” We know that cardiovascular disease is much more complicated than just simply cholesterol metabolism, and so in my opinion, we do ourselves and our patients no favors by making unsubstantiated claims based on theoretical benefit. Particularly when we do have actual outcome trial data demonstrating reduced risk of heart disease from another oil - olive oil!

Is canola oil a healthier choice for heart health than butter? Probably. Will it reduce your risk of heart disease? We don’t know.