Corn

Health Benefits
(Source: World's Healthiest Foods, George Mateljan)

Antioxidant Benefits of Corn

While it might sound surprising to some people who are used to thinking about corn as a plain staple food, a snack food, or a summertime party food, corn is actually a unique phytonutrient-rich plant that provides us with well-documented antioxidant benefits. In terms of conventional antioxidant nutrients, corn is not ranked by our algorithm as a good source of any. Instead, corn's phytonutrients have taken center stage in the antioxidant research. When all varieties of corn are considered as a group, the list of corn's key antioxidant nutrients appears as follows.

Basic Nutrient, Phytonutrient, and Antioxidant Benefits from Corn

While many people think about corn along the lines of a "staple food" that can be dried, ground, and then used to make corn meal, corn flour, and a variety of related foods, corn can also be enjoyed in fresh form and fresh corn can be the source of many key nutrients. The ear of cooked, yellow corn that we profile on our website is a good source of several B vitamins, including vitamin B3, vitamin B6, and pantothenic acid. In fact, in some cultures where corn serves as a major meal component, its vitamin B3 content can be especially important for preventing B3-deficiency related problems. Fresh corn is also a good source of fiber and of the mineral phosphorus. In short, it would be a mistake to think about this food as nothing more than a "staple."

In terms of phytonutrients, corn is best-known for its carotenoids. Lutein and zeaxanthin are the primary carotenoids found in corn. Yet also present are beta-carotene and beta-cryptoxanthin. The steaming of corn has been determined to better preserve the lutein and zeaxanthin in corn than either boiling of pressure cooking. (And, of course, Quick Steaming is our preferred cooking method for this food.)

The carotenoids listed above can all function as antioxidants, although they are not the only antioxidants present in corn. In addition to its carotenoids, corn also provides us with the antioxidant flavonoid quercetin and a variety of antioxidant organic acids. Included among these antioxidant organic acids are ferulic acid, diferulic acid, and coumaric acid. In blue and purple corn varieties, anthocyanin antioxidants are added to the rich mix of antioxidant nutrients present in corn. These anthocyanins include cyanidin-3-glucosides, pelargonidins, and peonidins. The anthocyanins in blue and purple corn have been used in animal studies to lower oxidative stress and reduce the presence of reactive oxygen species (ROS). And in lab studies, when cells have been incubated together with carotenoids extracts from corn, the antioxidant pathway genes in these cells show increased activity. 84 different genes in antioxidant pathways were analyzed in one study, and 28 of 84 of those genes were found to have increased activity—technically called gene expression—after the combination of cells with corn carotenoid extracts. In short, there is a research track record of antioxidant-related benefits from corn's unique variety of antioxidant nutrients.

Other Health Benefits from Corn

Research on overall health benefits from fresh corn is complicated for several reasons. First, a good bit of the current research on corn is carried out on processed corn components rather than whole fresh corn. For example, one popular new corn supplement called "soluble corn fiber" has been the topic of numerous research studies on digestive function, cardiovascular function, and anti-cancer potential for certain types of cancer (for example, colorectal cancer). However, soluble corn fiber (SCF) is a manufactured product made from hydrolysis of corn starch in a processing facility. The corn starch is processed in such a way as to produce resistant maltodextrins that contain glucose oligosaccharides together with glycosidic linkages. Intake of SCF and other supplement-type products made from corn is simply not comparable to the enjoyment of fresh corn on the cob. Second, corn is often studied in combination with other starchy grains, including grains like wheat. When results from these studies are obtained, it can be difficult to sort out the exact role played by corn. Finally, we've seen a good number of studies on corn extracts fed to rats and mice. While these studies can be very helpful in expanding our understanding of potential corn benefits, we do use animal studies on our website to confirm or rule out human health benefits. We like to see large-scale studies with real people enjoying everyday meals before linking foods to likely health benefits.

Despite the limitations described above, several areas of corn research show promising trends for health benefits. One of the liveliest areas of research involves corn and digestive function. Corn has long been known for its fiber content. An overwhelming amount of fiber in corn is insoluble. When people notice that corn hulls may not seem to be fully digesting, what they are noticing is the plentiful amount of cellulose and hemicellulose fiber that is present in the corn hulls. However, many parts of corn kernels can be fully digested, if not by human enzymes then by enzymes present in bacteria that live in the human digestive tract. While the exact steps in human digestion of whole corn are not yet clear, different components in the corn fibers—for example, arabinoxylans in the hemicellulose category of fibers—may be broken down by bacteria in our digestive tract and converted into health-supportive substances. Future research should help to clarify exactly how this process works. It should also lead to confirmation of unique digestive health benefits from enjoyment of corn.

Intake of soluble fiber has long been linked to cardiovascular benefits, including helpful changes in blood fat levels and composition. Studies on mice have shown corn extracts to help lower both total cholesterol and LDL-cholesterol.

Studies on SCF (the soluble corn fiber product described earlier in this section) have shown the ability of this corn derivative to impact bacterial composition in the lower intestine and the activity of bacterial enzymes. This impact, in turn, has been linked to better calcium absorption. Key bacteria involved in these studies include Bifidobacteria, Bacteriodes, Dorea, Ruminococcus, and Dialister. Other studies on SCF seem to confirm the connection between intake of these altered corn fibers and digestive function. What we hope to see in the near future are studies not on processed corn starch products like SCF, but on sweet corn that is being enjoyed in a freshly steamed form in an everyday meal plan.

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