Canola oil holds a slight nutritional edge over soybean oil for most people, largely because of its higher monounsaturated fat content and better ratio of omega-6 to omega-3 fatty acids. But the gap is narrower than marketing might suggest, and the real-world difference depends on how much oil you use, what you cook with it, and which version of each oil you buy. Both are refined vegetable oils with similar calorie counts and smoke points, and both are considered heart-healthy by mainstream nutrition guidelines.
The Fat Profile Is Where They Actually Differ
The single biggest distinction between these two oils is how their fats are distributed. Canola oil is roughly 60–65% monounsaturated fat (mainly oleic acid), about 28% polyunsaturated fat, and around 7% saturated fat. Soybean oil flips that balance: it is roughly 23% monounsaturated, about 58% polyunsaturated (dominated by linoleic acid, an omega-6), and around 15% saturated. Both contain the essential fatty acids your body cannot make on its own, linoleic acid (omega-6) and alpha-linolenic acid (omega-3), but canola oil delivers a considerably more favorable ratio between the two.
Animal research illustrates this difference clearly. In a mouse study comparing the two oils over 56 days, the canola-fed group accumulated higher levels of omega-3 fatty acids, including EPA and DHA, while the soybean-fed group accumulated more omega-6 fatty acids like linoleic and arachidonic acid. The omega-6-to-omega-3 ratio rose by about 45% in the soybean group while falling by roughly 32% in the canola group over the same period.1PubMed Central. The Dietary Replacement of Soybean Oil by Canola Oil Does Not Prevent Liver Fatty Acid Accumulation and Liver Inflammation in Mice That shift matters because Western diets already skew heavily toward omega-6, and a high omega-6-to-omega-3 ratio has been linked to chronic inflammation.
That said, soybean oil is not a poor source of essential fats. It actually delivers more total polyunsaturated fat per tablespoon than canola oil does. If your diet is otherwise low in omega-6, that is fine. The concern is that most processed and restaurant food in the United States already uses soybean oil extensively, so adding more at home can push an already lopsided ratio further out of balance.
What the Heart Research Shows
Both oils have been promoted as heart-healthy alternatives to butter and other saturated-fat-heavy cooking fats. The reasoning is straightforward: replacing saturated fat with unsaturated fat tends to improve blood cholesterol markers. But when you compare canola and soybean oil head-to-head, the cardiovascular evidence is surprisingly thin and somewhat mixed.
A mouse study supplementing diets with either soybean or canola oil found that the soybean-oil group had significantly higher total cholesterol, triglycerides, and HDL levels, leading the researchers to note that both oils had adverse effects on blood lipid profiles and heart tissue when consumed in large quantities.2Annals of Bangladesh Agriculture. Effects of Dietary Supplementation With Soybean And Canola Oil on Lipid Profiles and Heart in Swiss Albino Mice That finding is worth knowing but worth holding loosely: mice metabolize fats differently from humans, and the doses used in animal studies rarely mirror typical human intake.
On the human side, a randomized crossover trial tested whether partially replacing saturated fat with monounsaturated fat from canola oil would improve blood vessel function in people with or at risk of metabolic syndrome. The result was a null: there were no significant differences in flow-mediated dilation, which is a standard measure of how well arteries relax and expand.3PubMed Central. Effects of Diets Enriched with Conventional or High-Oleic Canola Oils on Vascular Endothelial Function: A Sub-Study of the Canola Oil Multi-Centre Intervention Trial 2 (COMIT-2), a Randomized Crossover Controlled Feeding Study That does not mean canola oil is bad for your arteries. It just means that swapping it in for other unsaturated fats does not produce a detectable vascular benefit in the short term. Most of the cardiovascular advantage of both oils comes from what they replace, specifically saturated and trans fats, rather than from some unique protective compound within the oil itself.
Liver Health and Fatty Liver Disease
One area where canola oil shows a more promising signal is non-alcoholic fatty liver disease. A meta-analysis of three randomized controlled trials found that canola oil consumption was associated with significant reductions in the liver enzymes ALT and AST, both markers of liver stress. Triglyceride levels also dropped, though with more variability across studies.4PubMed Central. Effects of Canola Oil on Hepatic and Cardiometabolic Markers in Non‐Alcoholic Fatty Liver Disease: A Systematic Review and Meta‐Analysis The total number of participants across those trials was only about 220, so the evidence is early-stage, but the direction is encouraging.
In an animal model comparing several vegetable oils fed as part of a high-fat diet, mice receiving canola oil showed reduced liver and abdominal fat compared to the other oil groups. Both canola and soybean oil groups had increased hepatic omega-3 levels relative to the high-fat control, but canola oil was the only one associated with measurable fat reduction in the liver itself.5PubMed Central. Effects of Different Vegetable Oils on the Nonalcoholic Fatty Liver Disease in C57/BL Mice The likely explanation loops back to the fat profile: canola oil’s higher monounsaturated fat content and better omega-6-to-omega-3 ratio may create a less inflammatory environment in the liver.
Interestingly, the same mouse study that found canola oil improved the omega-3 ratio also found that simply swapping soybean oil for canola oil did not prevent liver inflammation or overall fatty acid accumulation.1PubMed Central. The Dietary Replacement of Soybean Oil by Canola Oil Does Not Prevent Liver Fatty Acid Accumulation and Liver Inflammation in Mice So the liver story is nuanced: canola oil changes which fats accumulate and may improve certain biomarkers, but it is not a cure-all for what excess dietary fat does to the liver.
Weight and Body Composition
If you are choosing between these oils partly for weight management, the evidence leans slightly against soybean oil. A systematic review and network meta-analysis of randomized controlled trials looking at various edible oils and body weight found that soybean oil was associated with weight gain, along with palm and sunflower oils. The review did not single out canola oil for either weight gain or loss.6PubMed Central. The effect of different edible oils on body weight: a systematic review and network meta-analysis of randomized controlled trials Any single oil is still just a fraction of your total calorie intake, and both oils deliver the same 120 calories per tablespoon. But if the meta-analytic signal is real, the type of fat may matter beyond raw calorie counts, possibly through effects on inflammation or satiety hormones.
How They Behave in the Kitchen
Both canola and soybean oil are popular for frying, sautéing, and baking, but they do not perform identically under heat. Canola oil’s higher monounsaturated fat content gives it a structural advantage during prolonged cooking, because monounsaturated fats are more stable than polyunsaturated fats when exposed to heat and oxygen.
In a rotational frying study that pushed both oils through extended use, soybean oil produced the highest levels of anisidine, a marker of secondary oxidation products, with the peak reached by the tenth day. The half-life of tocopherols (vitamin E compounds that act as natural antioxidants in the oil) was only one to two days for both regular and modified soybean oils, compared to six days for a high-oleic, low-linolenic canola oil.7PubMed Central. Performance of Regular and Modified Canola and Soybean Oils in Rotational Frying That means the natural antioxidant protection in soybean oil breaks down much faster during repeated frying.
Repeated deep-frying degrades both oils predictably: the beneficial polyunsaturated fatty acids (linoleic and alpha-linolenic acid) decrease, while saturated and trans fats increase. This breakdown happens regardless of which oil you use, but oils with more polyunsaturated fat start with more material that can oxidize.8Malaysian Journal of Nutrition. Effects of repeated deep-frying on fatty acid profiles of potato fries and frying oils: soybean oil, canola oil and their 1:1 blend Breeding has addressed this problem to some extent. Low-linolenic versions of both soybean and canola oil produce significantly fewer polar compounds, free fatty acids, and foam during frying compared to unmodified versions.9Journal of the American Oil Chemists’ Society. Frying stability of soybean and canola oils with modified fatty acid compositions
For everyday home cooking where you use oil once and discard it, the stability difference is minor. It becomes much more relevant in commercial kitchens or if you reuse frying oil multiple times.
Flavor and Sensory Differences
Both oils are deliberately refined to be as bland as possible, which is part of why they are so widely used in food manufacturing. Sensory panel testing has confirmed that both have mild odors and flavors overall, though canola oil scored highest for a slight fishy note, while cottonseed oil scored highest for a hydrogenated or waxy character.10OCL. Descriptive Sensory Profiling of Freshly Processed Commercial Peanut, Cottonseed, Canola and Soybean Oils In practice, most people cannot tell the two apart in cooked food. The fishy note in canola oil is generally only detectable in fresh, unheated oil and tends to disappear during cooking.
The High-Oleic Versions Change the Equation
A growing share of both canola and soybean oil on the market is now “high-oleic,” meaning the plants have been bred to produce oil with much more oleic acid (a monounsaturated fat) and less polyunsaturated fat. High-oleic canola oil can be over 70% monounsaturated. High-oleic soybean oil narrows the traditional gap considerably by pushing its monounsaturated fat content well above that of regular soybean oil.
Modeling based on U.S. dietary intake data found that replacing traditional soybean and canola oils with high-oleic varieties across the food supply would increase monounsaturated fat intake and reduce both saturated and polyunsaturated fat intake. The trade-off is that the shift could put certain age and sex groups at risk of inadequate intake of the essential fatty acids linoleic acid and alpha-linolenic acid.11PubMed. Modeled replacement of traditional soybean and canola oil with high-oleic varieties increases monounsaturated fatty acid and reduces both saturated fatty acid and polyunsaturated fatty acid intake in the US adult population In other words, if you already eat plenty of nuts, seeds, and fatty fish, high-oleic oils are a fine choice. If your diet is otherwise low in essential fats, a traditional version of either oil helps cover that gap.
Processing and What Gets Lost Along the Way
Both canola and soybean oil go through extensive refining: degumming, neutralization, bleaching, and deodorization. This process makes the oil shelf-stable, neutral-tasting, and high-smoke-point, but it also strips out some naturally occurring nutrients, including certain antioxidants and minor plant compounds. Refining can also generate small amounts of undesirable byproducts, including 3-MCPD esters and trace trans fats.12PubMed Central. Refining Vegetable Oils: Chemical and Physical Refining These concerns apply equally to both oils; neither has a meaningful processing advantage over the other.
Cold-pressed or “expeller-pressed” versions of both oils exist and retain more of their original antioxidants. They also tend to have lower smoke points and stronger flavors, which limits their versatility. If you are specifically looking for a less processed oil, cold-pressed canola retains more of its vitamin E and polyphenols, but the same is true of minimally processed soybean oil.
Where Canola Oil Came From
Canola oil is sometimes the subject of health rumors tied to its origins. The oil comes from rapeseed, a plant in the mustard family. Traditional rapeseed oil contained high levels of erucic acid, a long-chain fatty acid that caused heart lesions in animal studies. Canadian plant breeders in the 1970s developed “double-low” varieties with less than 5% erucic acid and reduced glucosinolate content, making the oil safe for human consumption.13PubMed Central. A Brief History of Canola Genetic Gains: From Classical Breeding to Genome Editing14Izvestiâ Timirâzevskoj selʹskohozâjstvennoj akademii. Oil yield of rapeseed plant – botanical nature, biochemical features and nutritional potential The name “canola” was coined to distinguish these food-grade varieties from industrial rapeseed. Modern canola oil typically contains less than 2% erucic acid. Claims that canola oil is “toxic” because of its rapeseed ancestry misunderstand what the breeding program accomplished: it is roughly analogous to saying modern sweet almonds are dangerous because bitter almonds contain cyanide compounds.
Environmental Footprint
If your oil choice extends to sustainability, the picture is mixed. A life cycle assessment comparing five major vegetable oils found that rapeseed (canola) oil produced lower greenhouse gas emissions than soybean oil and used less water. Soybean oil, on the other hand, required less total land area, partly because soybeans are a high-yield crop and the oil is a co-product alongside soybean meal for animal feed.15PRé Sustainability. Comparative life cycle assessment of five different vegetable oils Soybean farming has also drawn outsized attention for its role in deforestation, particularly in South America, though this concern applies mainly to soy grown for animal feed rather than for direct oil production. Neither oil is an environmental free lunch, and the specific footprint depends heavily on where and how the crop is grown.
Gut Microbiome Effects
Research into how dietary oils shape gut bacteria is still in its early stages, but some patterns are emerging. Data from the Canola Oil Multicenter Intervention Trial (COMIT) found that diets rich in monounsaturated fat (the type dominant in canola oil) and diets rich in polyunsaturated fat (the type dominant in soybean oil) shifted gut microbial populations differently. The monounsaturated-fat diets increased certain bacterial groups, while the polyunsaturated-fat diets favored others. These effects were more pronounced in obese participants than in overweight ones, suggesting that body mass itself is a bigger driver of gut microbiome composition than the type of oil you cook with.16PubMed Central. Interactions between Obesity Status and Dietary Intake of Monounsaturated and Polyunsaturated Oils on Human Gut Microbiome Profiles in the Canola Oil Multicenter Intervention Trial (COMIT) This area is too young to translate into practical advice, but it suggests that the type of fat in your oil could have downstream effects beyond simple calorie and nutrient delivery.
Pesticide Residues in the Finished Oil
Both canola and soybean crops are widely treated with pesticides, and trace residues can survive into the crude oil. Monitoring of crude seed oils has detected mainly organophosphorus insecticides in soybean, sunflower, and rapeseed oil, though at very low levels.17OCL. Unilever food safety assurance system for refined vegetable oils and fats Refining further reduces these residues. In laboratory testing of how well different oils absorb pesticide residues from contaminated solutions, soybean oil was actually the most efficient at pulling in several pesticide classes, including carbamates, organochlorides, and pyrethroids. Canola oil ranked second for many of the same categories.18Journal of Ginseng Research. Canola oil is an excellent vehicle for eliminating pesticide residues in aqueous ginseng extract That study was designed to evaluate oil as a tool for extracting pesticides from ginseng, not to assess dietary risk. But it does confirm that both oils are lipophilic enough to attract and hold fat-soluble pesticide residues. In practice, the refining process and regulatory limits keep residue levels in finished retail oils well below safety thresholds. If minimizing pesticide exposure is a priority, choosing organic versions of either oil is a more meaningful step than switching between the two.
Animal feeding studies have shown that even bound pesticide residues in soybean and canola plant material are bioavailable to some degree after ingestion, though they do not accumulate in organs like the liver, kidney, or heart over short feeding periods.19PubMed. Bioavailability in rats of bound pesticide residues from tolerant or susceptible varieties of soybean and canola treated with metribuzin or atrazine The practical takeaway is that refined oil from either crop, after standard processing and regulatory screening, presents minimal pesticide risk for consumers.