Nutrients in cooked corn

As high as an elephant’s eye

If you’ve ever driven through Maryland in the summer, you know there are two things you’ll see a lot of on the side of the road. One is abandoned cars, the reason for which I still can’t explain even after living here for 20 years. The other is pick-up trucks with hand-painted signs leaning on one tire advertising “Sweet Corn.”

There’s something about fresh corn out of a truck that just feels like summer. But with the bad news about carbs and starches in recent years, it’s easy to wonder whether we should be eating corn at all. Now a new study gives us a reason to stop and grab a few ears more often.

That’s a big cornfield

Imagine a cornfield the size of Pennsylvania, Ohio and Indiana put together. Immense as that would be, it would still be several thousand square miles smaller than the entire land area devoted to corn production in the U.S. So don’t worry about running out of corn. If anything, we have way too much – a troubling situation I’ll tell you more about in a moment.

For now we’ll turn to a surprising study from Cornell University that investigated the way the nutrients in corn are affected by cooking. In previous studies, the Cornell team found evidence that cooked fruits and vegetables retain their antioxidant benefits even though vitamin C is reduced by the cooking process. But they didn’t know if the same would be true with a grain, like corn. They knew that corn contains very high levels of ferulic acid, a chemical with antioxidant compounds, and so they set out to determine how ferulic acid would respond when cooked.

The team cooked loose kernels of corn for 10, 25 and 50 minutes. The results were dramatic. The amount of ferulic acid increased 240 percent in the batch cooked for 10 minutes, 550 percent in the batch cooked for 25 minutes, and 900 percent in the batch cooked for 50 minutes.

The lead author of the study, Rui Hai Liu, Cornell assistant professor of food science, pointed out that ferulic acid is bound to the corn’s insoluble fibers. Liu and his colleagues demonstrated that cooking releases the ferulic acid. Contrary to the accepted idea that the nutrients in food are reduced in the cooking process, in this case the valuable antioxidant qualities of corn are shown to substantially increase with longer cooking times.

Taking the good with the bad

That’s the good news about corn. The bad news is that most of us, at least in America, ingest corn in ways that don’t even resemble corn.

Writing in the New York Times, horticulturist Michael Pollan notes that in the 1980’s, the manufacturers of soft drinks and snack foods began switching from sugar to high-fructose corn syrup (HFCS) as their primary sweetener. In recent years HFCS has been used in the processing of a wide variety of foods such as bread, beer and pasta sauces. As a result, American adults get almost 10 percent of their calories from high-fructose corn syrup, and for many children that percentage is doubled.

And the evidence is mounting that it presents more health risks than just cavities.

Pollan cites a recent study from the University of Minnesota that investigated the way that the body metabolizes HFCS. The results indicate that HFCS elevates triglyceride levels in men shortly after eating, and may contribute to the risk of heart disease and obesity. Similar conclusions were reached in another HFCS study at the University of California.

Got corn?

Obviously, corn gets into our diet in all sorts of ways – some of those ways are good, and some are not so good. We would all do best to keep an eye on food labels and avoid high-fructose corn syrup.

In the meantime, you can support your local farmers by stopping off at their roadside stands and buying a few bags of fresh sweet corn. Then when it’s dinnertime, remember to leave the cobs on the boil for a little longer than usual for a side dish that will give your body a boost of helpful antioxidants.

To Your Good Health,

Jenny Thompson
Health Sciences Institute

Sources:
“Processed Sweet Corn Has Higher Antioxidant Activity” Journal of Agricultural and Food Chemistry, 8/14/02
“Cooking Sweet Corn Boosts its Ability to Fight Cancer and Heart Disease by Freeing Healthful Compounds, Cornell Scientists Find” Cornell News Press Release, 8/8/02
“Cornell Researchers Turn Conventional Thinking About Canned Corn on its Ear” American Chemical Society, 8/8/02
“When a Crop Becomes King” New York Times Editorial, 7/19/02