Mazola corn oil is a reasonable cooking oil that offers real heart health benefits compared to butter and other saturated fats, but it falls short of olive oil in several important ways. Whether it counts as “healthy” depends on what you’re replacing it with and how much of your diet it represents.
What’s Actually in Corn Oil
Refined corn oil is about 59% polyunsaturated fat, 24% monounsaturated fat, and 13% saturated fat. That fat profile is heavily weighted toward linoleic acid, an omega-6 fatty acid. A single tablespoon contains roughly 14 grams of total fat and 120 calories, with no protein, carbohydrates, or cholesterol.
One tablespoon also delivers about 10% of your daily vitamin E needs, which acts as an antioxidant in the body. But the standout nutrient in corn oil is something most people haven’t heard of: plant sterols, also called phytosterols. Corn oil contains about 0.77% phytosterols by weight, which is high compared to many other cooking oils. These compounds have a measurable effect on cholesterol absorption, which is where corn oil’s biggest health claim comes from.
The Cholesterol-Lowering Effect
Plant sterols in corn oil physically block your intestines from absorbing cholesterol. In a controlled study published in the Journal of Nutrition, researchers stripped the phytosterols out of corn oil and then added them back at different concentrations to isolate their effect. When participants consumed corn oil with its natural sterols intact, they absorbed 38% less cholesterol than when they ate the same oil with the sterols removed. Adding back just 300 milligrams of phytosterols (roughly the amount in two tablespoons of corn oil) reduced cholesterol absorption by about 28%.
This matters because researchers had long assumed corn oil’s cholesterol-lowering properties came entirely from its unsaturated fat content. It turns out the plant sterols deserve a significant share of the credit. Replacing saturated fats like butter with corn oil can lower LDL cholesterol, and the effect comes from both the shift in fat type and the phytosterol content working together.
The Omega-6 Problem
Corn oil has an omega-6 to omega-3 ratio of roughly 52 to 1. That’s dramatically lopsided. Most nutrition guidelines suggest a ratio closer to 4:1 or lower for optimal health. Omega-6 fats aren’t inherently harmful, but when they dominate the diet at the expense of omega-3s (found in fatty fish, flaxseed, and walnuts), the concern is that they could promote inflammation.
The clinical evidence on this point is more reassuring than you might expect. A review of randomized controlled trials found virtually no data supporting the idea that linoleic acid (the primary omega-6 in corn oil) increases inflammatory markers in healthy adults. Circulating C-reactive protein, one of the most common measures of systemic inflammation, showed no significant change across trials that varied linoleic acid intake. The same held true for a long list of other inflammatory biomarkers.
That said, if corn oil is your primary cooking fat and you don’t eat much fish, your overall dietary ratio will skew heavily toward omega-6. The issue isn’t that corn oil causes inflammation on its own. It’s that relying on it crowds out opportunities to get more omega-3s into your diet.
How It Compares to Olive Oil
Olive oil, particularly extra virgin, consistently outperforms corn oil in research. In one comparative study, rats fed olive oil showed higher activity of key antioxidant enzymes in the liver and white fat tissue compared to those fed corn oil. The corn oil group also showed greater impairment in several markers of cellular metabolism, including parameters related to how the body processes glucose.
The American Heart Association’s 2026 dietary guidance recommends “liquid nontropical plant oils” as part of heart-healthy eating, specifically naming soybean, canola, and olive oils. Corn oil fits the broader category of nontropical plant oils and is a clear upgrade over butter, beef tallow, and tropical oils like coconut and palm oil. But it doesn’t get the same spotlight as olive oil, which brings a richer set of antioxidants and polyphenols that corn oil lacks after refining.
Cooking Performance and Stability
Corn oil has a smoke point between 400 and 450°F, which makes it suitable for sautéing, stir-frying, and most home cooking. Its neutral flavor also makes it versatile for baking. However, oils high in polyunsaturated fats are less chemically stable at high temperatures. When any oil reaches its smoke point, it begins breaking down and releasing free radicals, which are unstable molecules that can damage cells. The beneficial nutrients and phytochemicals in the oil also degrade at that point.
For deep frying or prolonged high-heat cooking, oils with more monounsaturated fat (like avocado oil or refined olive oil) hold up better. Corn oil works fine for moderate-heat cooking and occasional frying, but it’s not the most stable option if you’re regularly cooking above 400°F.
How Corn Oil Is Made
Mazola and other commercial corn oils go through significant processing. The oil is first extracted from corn germ (not the whole kernel) using mechanical pressing followed by hexane, a chemical solvent. After extraction, the oil goes through alkali washing, water washing, and bleaching with activated carbon to remove color compounds. This refining process produces a clean, neutral-tasting oil, but it strips out some of the protective compounds found in less processed oils like extra virgin olive oil.
This level of processing is standard for most affordable cooking oils on the market, including canola and soybean oil. It’s not unique to corn oil or a reason to avoid it, but it does explain why refined corn oil lacks the antioxidant depth of cold-pressed or minimally processed alternatives.
The Bottom Line on Corn Oil
Corn oil is healthier than butter, lard, and coconut oil for your cardiovascular system. Its plant sterols offer a genuine, clinically demonstrated benefit for reducing cholesterol absorption, and swapping it in for saturated fats will lower LDL cholesterol. The omega-6 inflammation concern, while theoretically logical, hasn’t held up in clinical trials measuring actual inflammatory markers in humans.
Where corn oil falls short is in comparison to olive oil, which delivers stronger antioxidant protection and a better fatty acid balance. If you’re choosing between corn oil and butter, corn oil is the better pick. If you’re choosing between corn oil and extra virgin olive oil, olive oil wins on the overall evidence. Using corn oil as one of several plant oils in your kitchen, rather than your only cooking fat, is a practical way to get its benefits without overloading on omega-6 fats.