January 25, 2001

A new kind of corn, developed by a researcher at USDA's Agricultural Research Service, may help ensure that people get more of the zinc they need for good health. The new corn has about 65 percent less phytic acid, also known as phytate, than conventional corn. That's a plus, USDA says, because phytate can interfere with the body's ability to absorb certain nutrients–including zinc, an essential mineral.

Physicians and scientists from the University of Colorado Health Sciences Center in Denver, and an ARS geneticist in Aberdeen, Idaho, collaborated on the study to test the body's ability to absorb zinc from the low-phytate corn. Five healthy volunteers, age 23 to 39, ate menus featuring polenta, a cooked, coarse cornmeal, for two days. Cornmeal from the low-phytate corn was used to make the polenta one day, and cornmeal from conventional corn was used the next. Both kinds of cornmeal were spiked with a stable isotope of zinc that can be easily detected by laboratory instruments.

Analysis of fecal samples showed that the volunteers absorbed about 78 percent more zinc, on average, from the low-phytate corn than from the conventional corn. The Colorado researchers used the findings as the basis of a larger, follow-up study with Guatemalan villagers.