Researchers studied the effects of both oils on 54 healthy men and women. For 21 days, participants were either given four daily tablespoons of corn oil or four tablespoons of olive oil. The results? Corn oil was shown to reduce LDL cholesterol (the bad kind) by almost 11%, while olive oil only lowered it 3.5%. Study participants experienced an 8.2% decrease in total cholesterol with corn oil, compared to just a 1.8% decrease with olive oil. Why the different effects? Corn oil contains more phytosterols—a group of compounds found in plant cell membranes that help block cholesterol absorption in the digestive system—than olive oil; there are 132 mg in one serving of corn oil, compared to 30 mg in a serving of olive oil. But don’t ditch your extra virgin olive oil (EVOO) just yet—researchers observed a lower heart rate and diastolic blood pressure when people were eating foods with olive oil.  “Both oils have some favorable affects,” says study author Kevin C. Maki, PhD, who performed the research at Biofortis Clinical Research (a research company hired by Mazola Cooking Oil to conduct the study). “I think that people should eat a variety of oils; corn oil and olive oil are both good options.” Sharon Palmer, a registered dietitian from LA, agrees. “This study supports that corn oil can be a heart-healthy fat, which makes sense, as it is rich in polyunsaturated fatty acids (PUFAs) and monounsaturated fatty acids (MUFAs). However, it’s important to remember that the EVOO also promoted positive results in this study, and hundreds of other studies have found benefits with this heart-healthy oil, as well.” The most important thing to keep in mind, says Palmer, is that focusing on unsaturated plant oils overall—about 20 to 35% of your daily calories should come from these healthy fats—is a much healthier diet patten than a diet high in saturated fats or even a strict low-fat diet. Your best bet: “Use a variety of plant oils so that you’re getting PUFAs and MUFAs in your diet.”  More from Prevention: The Best Cooking Method For Every Kind Of Oil