Corn: A 9,000-Year-Old Staple With 3 Main Health Benefits

The Aztecs considered corn a gift from the gods, and there may still be a kernel of truth to that. Grown for more than 9,000 years, corn has served as a staple on our plates, food for animals, and even as a source of fuel. Corn provides abundant nutrition with every bite off the cob, delivering digestive-supporting insoluble fiber, eye-protecting carotenoids such as lutein and zeaxanthin, and essential B vitamins such as folate.

However, the corn once revered by ancestors is no longer as natural, with more than 90 percent of U.S. corn currently genetically modified, raising questions about whether genetic modification changes its nutritional value or health benefits.

(Illustration by Ran/The Epoch Times) — Illustration by Ran/The Epoch Times

“Corn is often referred to as ‘only’ a starch; however, when compared to many grains, whole corn has an interesting variety of nutrients,” Dr. Ayesha Bryant told The Epoch Times in an email.

One medium-sized ear of corn provides essential nutrients, including 9 percent of the daily value for fiber, much of it from the bran (pericarp), the kernel’s outer layer, and 6 percent of the daily value for folate.

The kernel’s hue can reveal clues about the antioxidants and other phytochemicals it contains, Kelly Burgess, registered dietitian, told The Epoch Times. “In general, pigmented or colored whole corn contains substantially more antioxidants than white corn.”

Yellow and orange corn contain carotenoids, including lutein, zeaxanthin, and beta-carotene, as well as phenolic compounds such as ferulic acid.

Blue corn provides anthocyanins, including cyanidin-3-glucoside, along with other phenolic compounds with antioxidant properties.

Purple and purple-black corn are particularly rich in anthocyanins. They also provide an array of other plant compounds.

“They [red and purple-black corn] contain flavonoids, amino acids, nucleotides—the building blocks of DNA and RNA—and other antioxidant and inflammation-lowering compounds,” Burgess said.

Red corn provides anthocyanins and other flavonoids and may contain relatively higher amounts of protein, oil, ferulic acid–a phenolic antioxidant, much of which is bound to the grain’s cell walls–and minerals than other varieties.

Genetically modified (GM) corn is primarily engineered for resistance to certain insect pests or tolerance to specific herbicides, rather than to change its nutritional value.

Research has not established that non-GM corn is inherently more nutritious than approved GM corn, and nutritional differences among corn varieties can be influenced by genetics, growing conditions, and processing.

Nutritional composition is one part of the conversation around genetically modified organisms (GMOs). Widespread adoption of herbicide-tolerant crops has been accompanied by increased glyphosate use, Burgess said.

“Glyphosate is now a concern for human and environmental health. Some of its original advantages have lessened as weeds have become resistant, and heavy use has made glyphosate widespread in soil, water, air, and our food supply,” she said.

If avoiding GM corn is a priority, look for products labeled USDA Organic or Non-GMO and ask local growers about the varieties and farming practices they use.

Beyond whether corn is genetically modified, Bob Jones, a regenerative agriculture and soil health expert, told The Epoch Times that consumers should also consider how it was grown.

“Soil health is the number one promoter of high-quality produce; mineral content and biological activity are also very important,” he said.

As a grain, corn’s job is to make you full—but it does more than that.

Feeds Beneficial Gut Bacteria

“The main fiber in whole corn is insoluble fiber from the corn bran, which does not dissolve in water. Whole corn also contains resistant starch. Together, insoluble fiber and resistant starch add bulk to stool, help you feel full faster and stay full longer, and help move stool through the gastrointestinal tract to prevent constipation,” Burgess said.

Resistant starch–which is a carbohydrate that escapes digestion in the small intestine—reaches the colon, where it is fermented and may influence gut health.

In the colon, the fiber and resistant starch feed beneficial gut bacteria that produce short-chain fatty acids, including butyrate, Burgess said.

Butyrate and other short-chain fatty acids can help protect gut cells, lower inflammation, strengthen the intestinal barrier, and may even help protect against colon cancer, she said.

Research using corn-derived resistant starch helps explain how this process may work. A 2021 study published in Frontiers in Microbiology found that resistant starch promoted short-chain fatty acid production through interactions among different gut bacteria. Certain bacteria specialize in breaking down resistant starch and can provide substrates that other microbes use to produce short-chain fatty acids.

High-amylose corn, a specially bred corn that contains long-chain starch and particularly large amounts of resistant starch, has also been studied for possible metabolic effects.

A 2022 study published in the International Journal of Molecular Sciences found that high-amylose corn resistant starch altered the gut microbiome, bile acid metabolism, and liver fat accumulation. However, this research involved a specialized resistant starch often used as an ingredient in processed foods and baked goods rather than ordinary whole sweet corn, so the findings don’t necessarily translate directly to eating corn on the cob.

Supports Eye Health

“Corn is a notable whole-food source of the xanthophylls lutein and zeaxanthin, powerful antioxidants that help protect the macula, the part of the retina responsible for central vision and seeing fine details,” Burgess said.

An analysis of 33 fruits and vegetables found that lutein and zeaxanthin accounted for more than 85 percent of the total carotenoids in corn, with lutein alone accounting for about 60 percent.

Carotenoid levels can vary considerably by corn variety. Researchers developed a biofortified, deep orange-yellow sweet corn containing nearly 10 times as much zeaxanthin as standard varieties. The variety was created through conventional breeding rather than genetic engineering to increase its naturally occurring pigments.

A study of 3- to 5-year-old Zambian children found that biofortified orange maize increased blood levels of zeaxanthin and other carotenoids. Researchers found evidence that beta-carotene from the corn was converted into retinol, a form of vitamin A, needed for night vision, Burgess said.

Promotes Antioxidant Benefits

“Ferulic acid has both antioxidant and anti-inflammatory properties. It helps neutralize harmful compounds that can damage cells and reduces cellular stress associated with disease. It also helps turn down chemical signals that promote inflammation,” Burgess said.

One of the more unusual things about corn is that cooking it may actually release more of these antioxidant compounds from cell walls.

“Unlike some nutrients that decrease with heat, ferulic acid in whole corn is not reduced by cooking or boiling, or when whole corn is prepared as popcorn or porridge,” Burgess said.

In one study of sweet corn, heating it at about 240 degrees Fahrenheit for 25 minutes increased total antioxidant activity by 44 percent and free ferulic acid by 550 percent.

Newer research suggests the cooking method may matter as well. A study published in Foods found that high-pressure boiling was the most effective processing method tested for fresh corn. The combination of heat and pressure helped break down cellular structures and increased levels of key carotenoids, including lutein and zeaxanthin, as well as polyphenols such as ferulic acid by 20 percent to 42 percent.

Additional Benefits

An old folk remedy of making tea from corn silk to treat high blood pressure may have some scientific basis. A 2019 study in rats found that boiled corn silk extract lowered blood pressure and inhibited an enzyme involved in blood pressure regulation.

An animal study published in Microbiology Spectrum found that corn silk extract lowered blood pressure while altering the gut microbiome, strengthening intestinal barrier function, reducing systemic inflammation, and increasing nitric oxide availability, which helps blood vessels relax. Fecal transplantation experiments suggested that changes in the gut microbiome contributed to these effects.

While corn-silk extracts have lowered blood pressure in animal studies, providing a basis for further research, these findings do not establish that ordinary corn-silk tea treats hypertension in people.

Research has investigated ferulic acid for effects extending beyond its antioxidant activity, including potential roles in cardiovascular and metabolic health.

“Laboratory and animal studies have shown that it can help protect the lining of blood vessels and the heart, lower cholesterol, increase insulin secretion and control spikes in blood glucose, and affect how certain genes are turned on or off in ways that may influence cancer development,” Burgess said.

The fiber and resistant starch in whole corn can also help reduce spikes in blood glucose and insulin and help maintain healthy blood cholesterol levels to support heart health, Burgess added.

When it comes to corn, a few small strategies can help you get the most bang for your nutrient buck.

1. Cook It: Heat can break down corn’s plant cell matrix and release some of the ferulic acid bound within its cell walls. While cooking can increase the accessibility of certain compounds, the method matters. Steaming may preserve more antioxidants than boiling, which can cause water-soluble compounds to leach into the cooking water.

“Boiling causes the greatest loss of anthocyanins and phenolic compounds because heat breaks them down and some leach into the cooking water. Baking also reduces antioxidants because of the high heat, while steaming preserves more of them,” Burgess said.

2. Pair With Healthy Fat: Lutein and zeaxanthin are fat-soluble carotenoids, meaning some dietary fat can help the body absorb them.

“Eating whole corn with a small amount of fat can also help the body absorb more lutein and zeaxanthin. However, the type of fat may matter. For a nutrient-rich combination, pair whole corn with other fiber-rich plant foods and whole-food sources of healthy fats, such as avocado, nuts, and seeds,” Burgess said.

3. Consider Nixtamalized Corn: Nixtamalization is a traditional process that cooks and soaks corn in an alkaline solution. “[Corn] also contains niacin, although the body absorbs less of it unless the corn undergoes nixtamalization. This process involves soaking and cooking corn in an alkaline solution made with calcium hydroxide, or slaked lime, and water,” Burgess said.

Nixtamalized corn is used to make arepas, gluten-free pasta, hominy, masa harina, tortillas, and tamales, she added.

Corn is best enjoyed as farm-fresh as possible, but proper storage can help preserve its texture and quality.

Fresh Corn: Keep in the refrigerator with the husk on. Place ears in a loose plastic bag or produce bag. Use it as soon as possible. Don’t shuck until ready to eat. Removing the husk exposes the kernels to air and speeds moisture loss.
Cooked Corn: Refrigerate in an airtight container and use within three to four days.
To Freeze Fresh Corn: Blanch it briefly in boiling water, cool it in ice water, then remove the kernels or freeze whole ears in airtight freezer bags.

1. Buy Fresh: For the sweetest sweet corn, Jones recommends sourcing it locally and eating it as close to harvest as possible. “The biggest factor in good sweet corn is harvesting it by hand and consuming it as close to harvest as possible,” Jones said.

“With sweet corn, as is true with all vegetables, freshness is huge, as is the least amount of cooking possible. Raw in the field is the best you could possibly do; if that’s not possible, buy local and know your farmer.”

2. Don’t Overcook: Fresh corn doesn’t need much cooking. Briefly boiling, steaming, grilling, or sautéing the kernels is usually enough to heat them through while preserving their naturally sweet flavor and crisp texture. Overcooking can make the kernels tougher and dull their flavor.

3. Try Grilling in the Husk: For a simple, smoky preparation, briefly soak whole ears of corn, then grill them in their husks. The husks help trap moisture and steam the kernels as they cook, while the grill adds a subtle smoky flavor.

4. Save the Cobs: Once you’ve removed the kernels, don’t toss the cobs. Simmer them in water to make a naturally sweet corn broth that can add depth to soups, risotto, sauces, and other dishes.

5. Preparation: How you cook corn can also change the amount of resistant starch. When cooked starchy foods cool, some of their starch undergoes retrogradation, reorganizing into forms that resist digestion. Cooking and then cooling corn-based foods may therefore increase their resistant starch content. “Repeating the cooking-and-cooling process can further increase resistant starch,” Burgess said.

This easy salad brightens any meal as a side dish or stands alone as the main event. A drizzle of healthy oil adds richness while helping your body absorb fat-soluble nutrients. Toasting the quinoa adds an extra layer of nuttiness. Tossing the ingredients together and dressing the quinoa with olive oil and lime juice while it’s still warm helps it soak up more flavor.

To turn the salad into a heartier entrée, add half a cup of chopped grilled chicken or 3 ounces of grilled flank steak.

Prep time: 15 minutes
Total time: 40 minutes

Serves: 6

Ingredients

2 cups cooked quinoa
2 cups water
2 ears fresh corn, husks and silk removed
1 tablespoon extra-virgin olive oil or avocado oil
1/2 red onion, thinly sliced
1/2 cup cilantro, chopped
1 red bell pepper, diced
1 (15-ounce) can black beans, drained and rinsed
Juice of 1 lime
Salt to taste

Instructions

Place the quinoa in a fine-mesh sieve and rinse thoroughly under cold water, using your hands to swish it around. Drain well.
Place a saucepan over medium-high heat and add the drained quinoa. Toast the quinoa, stirring constantly, until completely dry, about 1 minute. Keep the quinoa continuously moving to avoid burning.
Stir in 2 cups of water and a generous pinch of salt and bring to a boil. Reduce the heat to low, cover, and cook for 15 minutes.
Turn off the heat and let the quinoa sit, covered, for 10 minutes. Remove the lid and fluff gently with a fork.
Meanwhile, cut the corn kernels from the cobs. Heat a skillet over medium-high heat with a small drizzle of olive or avocado oil. Add the corn and cook, stirring occasionally, until just tender and lightly browned, about three to five minutes.
In a large bowl, combine the warm quinoa, corn, red onion, cilantro, bell pepper, and black beans.
Whisk the lime juice with the remaining oil and a pinch of salt. Pour over the salad and toss to combine. Season with additional salt to taste.

Consider the form of corn. Whole-kernel corn contains fiber and resistant starch, but highly refined corn ingredients can behave differently and affect blood sugar. Cornstarch is rapidly digested and can raise blood glucose quickly, while high-fructose corn syrup is an added sugar.

People with Type 2 diabetes or insulin resistance should pay attention to portions and limit highly processed foods made with refined corn ingredients and added sugars.

“Refined, degermed, and extruded corn products, such as flaked corn cereals and corn chips, should not be considered nutritionally equal to whole corn. Processing can remove or alter parts of the whole kernel that provide fiber and other beneficial nutrients, and these products may produce a greater rise in blood sugar,” Burgess said.

Digestive issues are also a consideration. The outer layer of corn kernels contains insoluble cellulose, a type of fiber that humans cannot fully digest. Eating large amounts may cause bloating, gas, or changes in bowel movements in some people. Sweet corn also contains sorbitol, a FODMAP that can trigger symptoms in people who are sensitive to FODMAPs.

Lastly, while a true corn allergy is uncommon, reactions can range from hives and digestive symptoms to anaphylaxis in severe cases. People with a confirmed corn allergy may also need to check ingredient labels carefully, since corn and corn-derived ingredients are found in many processed foods.

An ear of corn almost always has an even number of rows, usually 16.
Every single silk thread on an ear of corn connects to a single potential kernel.
Glass gem, also called rainbow corn, has translucent, jewel-toned kernels in shades of purple, blue, pink, and green.
The corn we eat today has a wild ancestor, teosinte, that has tiny, hard seed clusters.
The average corn stalk grows about eight feet high, but the tallest on record is close to 45 feet.
Every continent grows corn except for Antarctica.

If your kids are hesitant to eat corn, start by making it fun. Cut cooked corn on the cob into 2- to 3-inch mini rounds and insert a popsicle stick into the core for a kid-friendly handle. You can also make corn ribs by slicing a cob into quarters lengthwise, then roasting or air-frying the pieces. As they cook, the corn curls slightly, giving them a rib-like shape that’s fun for kids to pick up and eat.

For kids who aren’t fans of whole corn kernels, blend cooked corn into a smooth puree and stir it into foods they already enjoy. Try mixing it into mac and cheese, cornbread, or cheese quesadillas for an easy way to include it without making it the focus of the meal.

Play with texture by making corn crispy and crunchy. Toss loose corn kernels with a drizzle of olive oil and a little salt, then air-fry or oven-roast them until they’re golden and slightly crispy.

What kid doesn’t like pancakes? Add whole corn kernels to a slightly sweet pancake batter and cook as usual. Serve the pancakes with a little maple syrup or a yogurt dip for a sweet-and-savory breakfast or snack.

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