Corn 101: A Complete Guide

Corn pops up just about everywhere: corn on the cob, cornbread, corn salad, corn syrup, and of course, popcorn. Despite how popular it is, however, there’s a lot you probably don’t know about corn.

For one, corn can be considered both a vegetable and a grain, according to the U.S. Department of Agriculture (USDA). When eaten fresh off the cob, corn is considered a vegetable, although it’s never really enjoyed the healthy reputation of its fellow produce because it tends to be high in carbohydrates. Yet it also contains resistant starch, a kind of prebiotic fiber that fuels a healthy gut, and antioxidants, among other essential nutrients.

In other cases, when corn is fully mature, dried, and milled into cornmeal or other products that include all parts of the grain (the bran, endosperm, and germ), it is considered a whole grain. Eating a diet high in these types of grains have been linked to numerous health benefits, including a longer life, according to research published in PLoS Medicine in February 2022.

So, where do nutrition experts fall on incorporating corn into a healthy diet? Read on for everything you need to know.

Corn is the name used for both the tall grass of the plant and its edible seeds, according to Britannica. The crop, also known as maize, was first domesticated in Mexico about 10,000 years ago, and is now grown worldwide and is the third-largest plant-based source of food. Corn is considered a cereal grain, but unlike others is naturally gluten-free.

You may have seen yellow and white sweet corn at the grocery store, but there are other types of corn that are used for different purposes. Here is a rundown, according to the American Farm Bureau Foundation for Agriculture:

• Dent corn, also called field corn, has a dent in the kernel. Most of the corn that’s grown in the United States is this variety, which is used for livestock feed.
• Sweet corn is the type you eat on the cob. It’s higher in sugar, so it has a sweet taste. You’ll find it in the produce section of grocery stores and in farmers’ markets when sweet corn is in season.
• Flint corn is colorful dried corn that’s usually used for decoration. You’ll often see it displayed for fall holidays like Halloween and Thanksgiving.
• Popcorn is a type of flint corn. It contains moisture, and heating the kernels builds pressure from the moisture that eventually makes the kernels explode.

While yellow and white sweet corn are what you’re likely to see most often, you can find blue and purple corn on the market as well. A study published in Chemistry Central Journal reported that blue corn contains antioxidants that are being studied for their possible role in fighting cancer. And according to the USDA, purple corn may reduce your risk of major diseases such as heart disease, cancer, and diabetes.

“I remember growing up learning that corn is a starchy vegetable, and you shouldn’t eat a lot of it, or you’re going to gain weight. But actually, it’s absolutely healthy for you and will make you feel full because of the fiber,” Taub-Dix says. “I have never, in 30-plus years that I’ve been in business, met a patient who was overweight because they ate too many vegetables.” That said, a typical recommended serving of starchy vegetables like corn is ½ cup.

Resistant starch, such as that found in corn, can help you stay fuller for longer stretches of time, which can help to naturally regulate your appetite and keep you from overeating. A meta-analysis in February 2021 in Clinical Nutrition ESPEN found that people who ate more resistant starch reported a decrease in appetite.

“Corn is also a nutrient-dense food, and when you replace heavily processed foods with whole foods, you get benefits with hunger management, and it’s easier to eat within your body’s needs,” Cassetty says. “That could help you maintain or potentially lose weight if it helped you reach a calorie deficit.”

Choosing popcorn over less-nutritious crunchy snacks may also help you consume fewer calories. Popcorn is a high-volume snack. “A serving is 3 cups, which is a very physically and visually satisfying amount,” Cassetty says. In those 3 cups, you get 90 calories and 3 g of fiber.

Corn is a nutritious whole, plant-based food, and most people can enjoy it as part of a balanced diet without worry. But there are a few side effects to note.

Side Effects

• You might see corn in your poop. Spotting whole kernels is no reason for alarm. The outer shell of a corn kernel is made of tough-to-digest cellulose, so it passes through your digestive system intact, according to research published in 2021 in Advances in Physiology Education.
• Corn likely contains genetically modified organisms (GMOs). Most of the corn grown in the United States has been genetically modified in some way, according to the U.S. Food and Drug Administration (FDA). Usually, this is done to make the crop resistant to pests and diseases. While some people try to avoid GMOs in their food, Taub-Dix says there’s no evidence that genetically modified corn poses a risk to us, and the FDA reports that GMO foods are as healthy and safe as non-GMO foods.
• Corn may cause some discomfort in people with digestive disorders. This vegetable is among the hard-to-digest carbohydrates considered a FODMAP, an acronym for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Eating corn may trigger gas, bloating, and abdominal discomfort in people who are sensitive to FODMAPs, such as those with irritable bowel syndrome (IBS), according to the University of Virginia. Additionally, people with inflammatory bowel disease may see a decrease in their symptoms if they follow the Specific Carbohydrate Diet, which excludes corn, according to the Crohn’s and Colitis Foundation.

Is It Possible to Be Allergic to Corn?

Corn is not considered a major allergen, according to a survey published in 2020 in Nutrition Today. But corn allergies are still possible, so people who are allergic need to avoid corn.

If you’re a fan of the freshest sweet corn, you might want to grow your own. The Old Farmers Almanac says you’ll need 60 to 100 frost-free days in your area to grow corn. You can choose a mix of early and late-season varieties to make sure your corn harvest lasts as long as possible.

Plant corn in moist but well-drained soil with six to eight hours of direct sunlight. Sow seeds 1.5 to 2 inches deep and 2 to 4 inches apart in a block, and water well. Thin them to 12 to 24 inches apart when they are about 4 inches tall. Mound soil around the base when they are 12 inches tall to help them stay straight. Shake the stalks every few days to encourage pollination. Harvest when ears are rounded, tassels are turning brown, and kernels are full.