Apparently corn isn't one 
http://www.whfoods.com/genpage.php?tname=foodspice&dbid=90What's New and Beneficial about Corn
You can get health-supportive antioxidant benefits from all varieties of corn, including white, yellow, blue, purple and red corn. But recent research has shown the antioxidant benefits from different varieties of corn actually come from different combinations of phytonutrients. In the case of yellow corn, it's the antioxidant carotenoids leading the way, with especially high concentrations of lutein and zeaxanthin. In the case of blue corn, it's the anthocyanins. There's one particular hydroxybenzoic acid in purple corn—protocatechuic acid—that's also been recently linked to the strong antioxidant activity in this corn variety.
In research on carotenoid antioxidants in food, there has been ongoing debate over the availability of all carotenoids in any particular food if one or two specific carotenoids are present in unusually high amounts. Because yellow corn is a high-carotenoid food that contains highly differing amounts of individual carotenoids, researchers have long wondered whether it is possible to get health benefits from all of the carotenoids in yellow corn when their concentrations are sometimes so different. In yellow cornmeal, the carotenoids lutein and zeaxanthin fall into the high concentration category and reach a level of 1,355 micrograms per 100 grams. That level is nearly 14 times as high as the level of beta-carotene (97 micrograms per 100 grams). But thanks to recent research, we now know that absorption of beta-carotene from yellow cornmeal is only mildly compromised by the high levels of lutein and zeaxanthin in the cornmeal. In other words, in terms of carotenoid nourishment, we appear to get health benefits from all of corn's diverse carotenoids!
We correctly think about corn as a good source of fiber. Corn is a food that gives us plenty of chewing satisfaction, and its high ratio of insoluble-to-soluble fiber is partly the reason. Past researchers have not been clear, however, about the ability of corn fiber to nourish our lower digestive tract. When you look at foods as a whole, they contain many different types of fiber, and when certain types of fiber reach the lower part of our large intestine (especially certain types of soluble fiber) they can be metabolized by intestinal bacteria into short chain fatty acids (SCFAs). This process not only helps support healthy populations of friendly bacteria in our large intestine, but also provides a direct supply of energy (in the form of SCFAs) to the cells that line our large intestine. With this benefit of this extra SCFA energy supply, our intestinal cells can stay healthier and function at a lower risk of becoming cancerous. Recent research has shown that corn can support the growth of friendly bacteria in our large intestine and can also be transformed by these bacteria into SCFAs. These SCFAs can supply energy to our intestinal cells and thereby help lower our risk of colon cancer. The amount of corn fiber analyzed in recent studies has been relatively high at 12 grams per day. That's the same amount provided by about 2.5 cups of fresh corn. While that amount might be more than you would consume at a single meal, it's an amount that you might easily consume over the course of several days. We suspect that future research will demonstrate the risk-reducing effects of smaller amounts of corn consumed over a longer period of time.
