Q. Some dietary advice treats corn as a starch, but some says it’s a vegetable. Which is correct?

A. Helen Rasmussen, PhD, RD, FADA, LDN, a research dietitian at the HNRCA, answers: “There is a lot of confusion about where corn should fit in your dietary pattern, and for good reason. In the Dietary Guidelines for Americans, corn is classified as both a vegetable and a grain. Botanically, it’s actually a fruit! All grains (and many other foods we call vegetables) are the “fruiting” part of a plant—the part that’s derived from the flower or ovary.

“The real question, I think, when we discuss the identity of this versatile food, is a question of healthfulness. We tend to think of ‘vegetables’ as healthy foods, and ‘starches’ as less desirable carbohydrate-rich choices that will spike blood glucose levels or cause weight gain. So-called starchy vegetables (like corn, peas, potatoes, and winter squash such as butternut and acorn) have been demonized by the low-carb diet movement, but they are packed with health-promoting fiber, vitamins, minerals, and phytochemicals.

“Corn, like other whole grains, is rich in fiber. Fiber slows digestion, improves bowel regularity, helps keep you feeling satisfied, decreases the risk of blood sugar spikes, and helps to feed the good bacteria in your gut. Whole grain corn provides a good source (greater than or equal to 10 percent of the recommended Daily Value) of fiber, magnesium, phosphorus, manganese, selenium and thiamine. Yellow corn also contains more than 10 times the amount of vitamin A of other grains, along with antioxidants and carotenoids such as lutein and zeaxanthin, which are associated with eye health.

“Whole corn (on the cob, or frozen or canned ‘niblets’), popcorn (minus the butter and salt), whole grain corn flour, and some forms of masa are the good choices that can fit well into a healthy dietary pattern. Processed corn products (like corn chips and corn syrup), on the other hand, are not good choices.

“For those concerned about genetically modified (GM) foods, it’s interesting to note that, while the vast majority of corn crops in the U.S. are GM, the one percent grown for human consumption (sweet corn), is almost never grown from GM seeds.”