Like all oils, Mazola corn (which was the brand used in this test) is nothing but pure fat. That's why whether it's corn, canola, or olive oil, all of them are a 120 calories per tablespoon.
Is corn oil nutritious? Compared to the other most frequently used cooking oils, it's not much better or worse. All of them have a low amount of antioxidants. Sure, corn has an extremely low (very bad) omega 6 vs. omega 3 ratio of 83:1, but even high-quality EVOO is 13:1... both of these figures represent a total train wreck on your body, considering that we should be aiming for a 1:1 average in our diets.
The healthiest oil to use really should be based on smoke point, with higher being healthier. Why? Because on the low smoke point varieties, when they get too hot they create dangerous byproducts which are terrible for you. The molecules of fat are broken down into free-fatty acids and glycerol, the latter of which then degrades further and turns into free radicals and toxic fumes.
What is the smoke point of refined corn oil? 450 degrees Fahrenheit, which is quite high. The unrefined is significantly lower, at 320 degrees.
Research Support, Non-U.S. Gov't: Carlsen MH, Halvorsen BL, Holte K, et al. Nutrition Journal NIH Jan 2010