Soybean, canola, palm, and corn oil are the top four veg­etable oils con­sumed in the United States that have neg­ative health affects. | Pixabay

Why are some health-con­scious people rejecting canola and other genet­i­cally-mod­ified oil? Is there real science behind the counter-canola craze, or is it just another dieting fad? 

According to Harvard expert Guy Crosby, soybean, canola, palm, and corn oil are the top four veg­etable oils con­sumed in the United States. These oils are referred to as refined, bleached, deodorized oils (“RBD”), which describes the process by which they are man­u­fac­tured — and they aren’t just in your curly fries. They’re in every­thing from bread, to pre-cooked chicken, as well as desserts and snacks. Even many avowed health products, like protein powder, are pro­duced with one or more of these oils.

In the 50 years since canola oil was invented by Canadian sci­en­tists by genet­i­cally mod­i­fying the rapeseed plant to be edible by human beings, the product has been touted for its health ben­efits. This is due to its low sat­u­rated fat content. Sat­u­rated fats are what most nutri­tionists con­sider the “bad fats,” because they have been shown to increase overall cho­les­terol levels, espe­cially LDL (low-density lipoprotein), the bad cho­les­terol. While nat­u­rally-occurring fats like butter contain 7.2 grams of sat­u­rated fat per table­spoon, canola boasts a mere 1.7 grams. For this reason, among others, many man­u­fac­turers who hadn’t already switched to canola and other GMO — genet­i­cally mod­ified organism — oils had good reason to in 1990, when the FDA required nutrition labels on all packaged and sold food. With it’s low per­centage of sat­u­rated fats, canola oil appeared to be healthier.

Yet canola and other genet­i­cally-pro­duced oils have been con­nected to long-term ail­ments which the FDA-approved label doesn’t show, according to some nutritionists. 

Catherine Shanahan, author of “Deep Nutrition: Why Your Genes Need Tra­di­tional Food,” argues that the modern diet is the real root cause of many of the dis­eases we believe are incurable — including cancer. Among other diet rec­om­men­da­tions, Shanahan advo­cates cutting all veg­etable oils and most sugar from your diet. 

While they are low in sat­u­rated fats, Shanahan explains that “veg­etable oils contain mostly heat-sen­sitive polyun­sat­u­rated fats. When heated, these fragile fats turn into toxic com­pounds including trans fat” — the worst kind of dietary fat. Since veg­etable oils are most often used in frying, baking, and cooking, the touted “low” sat­u­rated fat option is not what it says on the tin. 

Cooking with veg­etable oil also destroys complex nutrients in the foods you cook with it. Veg­etables, when cooked in canola oil, lose many of the vit­amins and antiox­i­dants they usually carry. Moreover, cooking veg­etable oils creates thou­sands of free radicals. 

“Chemists call this series of reac­tions a free radical cascade,” Shanahan says. “Free radical cas­cades damage normal PUFAs (polyun­sat­u­rated fats), turning them into ugly mol­e­cular ghouls (the Zombie effect). Just a little Mega­Trans in the bottle of canola oil can become a lot of Mega­Trans after you — or the cereal/donut/ frozen dinner man­u­fac­turers — cook with it.”

These free radical cas­cades harden arteries and damage other bodily tissues, gen­er­ating inflam­mation and inter­fering with normal meta­bolic function. 

Trans fats can also hurt your heart. Full of free rad­icals, they “attack the nitric oxide signal that arteries send when they sense oxygen levels are low,” Shanahan explains. Without that signal, muscles won’t get the oxygen they need to survive and stay active. More active muscles, like the heart, are par­tic­u­larly at risk, she says. 

Many of these “evil oils,” like canola, are pro­duced from the rapeseed, which harbors toxic com­pounds called erucic acid and glu­cosi­no­lates in its natural form, according to Healthline. The plant was genet­i­cally mod­ified in the 1970s to be edible, but it still doesn’t produce oil without first under­going a seven-step process. The rape seeds are cleaned, cooked, pressed, and chem­i­cally broken down with the aid of hexane, before the oil is ulti­mately extracted. Afterward, the canola meal is heated a third time, to remove the hexane through steam exposure. 

Some nutri­tionists cite hexane remainders as a reason enough to avoid veg­etable oils, but this isn’t the worst of it, according to Shanahan. The oil itself that is pro­duced in these processes is nothing more than “a chemical residue leftover from indus­trial farming, per­fectly engi­neered to prevent our cells from func­tioning the way they should,” she writes. 

The results of con­suming these oils range from acne, to cancer, to birth defects, clogged arteries, and even erectile dys­function. After eating french fries from week-old frying oil (frying oil is com­monly reused for countless batches of fried food), sub­jects in a New Zealand study were found to have barely-dilated arteries even four hours later. The oil pro­duced lethargy and blood vessel dysfunctioning. 

Veg­etable oil con­sumption is also a leading cause of acne, Shanahan says. 

“White blood cells mistake oxi­dized oil for the fatty acids that coat the surface of invasive bac­teria, and squads of white blood cells rush to the scene. And as you know, they show up swinging and strike at every­thing within reach. The acne lesion swells and reddens,” she writes.

Such acne, she says, is an inflam­mation gen­erated “not by infection but by oxi­dized oils.”

Con­suming veg­etable oils may even harm your children. An over­abun­dance of free rad­icals, also known as “oxidative stress,” can disrupt hormone pro­duction and interfere with hor­monal responses, according to a 2007 article in Genes to Cells. In 2006, a blood test of mothers whose babies were born with con­genital spinal and heart defects showed evi­dence of oxidative stress in the mother. 

What are the alter­na­tives? Shanahan and other nutri­tionists advocate for “tra­di­tional dieting,” or returning to natural foods, like butter, which are far lower in polyun­sat­u­rated fats. 

Shanahan also sug­gests a simple metric for remem­bering which oils are “evil” — if it pro­duces oil on it’s own (like olives, peanuts, and coconut), it’s OK. If not, it’s only suitable for machines.