The untold truth of canola oil

We're all guilty of indulging in some fried food from time to time, but most of us don't know the full extent of the impact that those greasy foods, and in particular the canola oil in which they are fried, have on our global economy or our health. For example, you might not know that the plant that canola oil comes from is almost identical to the rapeseed plant and represents the second-largest oil crop in the world after soybeans (via Science Direct). The name "canola" actually comes from the words "Canada" and "ola," which signifies oil, since it was Canadian scientists who developed an edible version of the rapeseed plant (i.e. the canola), per Healthline. The traditional rapeseed plant, and the oil made from it, contain high levels of compounds called erucic acid and glucosinolates, which are toxic to humans, while canola oil only contains very low levels of these compounds (via Mayo Clinic).

Since its discovery, canola oil has become an absolute kitchen staple thanks, in part, to its neutral flavor and relatively high smoke point of 400 degrees Fahrenheit (via MasterClass). However, while canola oil offers plenty of enticing characteristics, there are also some downsides to cooking with it or using it too often that could impact everything from our waistlines to our heart health to our memory, so read on to learn more about this seemingly simple fat. 

The truth about canola oil and heart health

Some oils are so heart and brain-healthy that we take them as supplements (think fish oil and those omega-3s). Well, canola oil is also rich in an essential polyunsaturated fat called omega-6 (via Healthline). Like omega-3, our body can't produce omega-6, so we need to get it from our diet. Unfortunately, most of the people eating the typical western diet are already getting more than enough omega-6, which can lead to unwanted inflammation in the body.

However, that's just one aspect of the heart health impacts of canola oil. When compared to other refined, bleached, and deodorized oils like soybean or sunflower, canola offers some unique heart benefits. For instance, it, like olive oil, is low in saturated fats and high in polyunsaturated fats that are deemed more "heart-healthy" and even contains phytosterols which can help decrease the amount of cholesterol the body absorbs (via Harvard School of Public Health). 

On the other hand, one study found that individuals who regularly cooked with canola oil were more likely to have metabolic syndrome, a collection of conditions (including high blood sugar and high blood pressure) which, together, increase your risk of heart disease (via the journal Nutrients). Meanwhile, multiple studies have shown that while replacing saturated fats with unsaturated vegetable oils did lead to lower cholesterol levels in patients, they also experienced significantly higher rates of death from cardiovascular disease and coronary artery disease (via Science Daily). Still, more research is needed. 

The impacts of canola oil on gut and brain health

Since its creation, canola oil has been the subject of some truly fascinating health studies. For instance, according to one 2017 study, a diet rich in canola oil was shown to have negative impacts on memory retention and learning ability in mice – effects modeling dementia (via Science Daily). In fact, the mice that were fed canola oil demonstrated an increase in amyloid-beta plaques, which are believed to be involved in developing Alzheimer's disease, and damage to their synapses (the structures responsible for communication between brain cells) compared to the control group (via Medical News Today).

In another study, fried canola oil was compared to fresh canola oil to see if the act of heating the oil had any impact on inflammation in mice with IBS and colon cancer. According to the study, conducted at UMass Amherst, the canola oil that had been heated up to 325 degrees Fahrenheit (approximately the temperature at which falafel is fried) had a much greater inflammatory effect than the un-fried canola oil (via UMass). In fact, the mice that were fed the fried canola oil saw their colon tumors double in size compared to the control group, giving us yet another reason to cut back on fried foods, even if they're fried in healthier oils.