Jan. 4, 2008 — Stephen Macko says one word in the film's trailer: "Pork." He says it authoritatively, with a firm downward gesture of the hand.

The first three minutes of the new documentary "King Corn" take place in his stable isotope lab at the University of Virginia. What Macko, a professor of environmental sciences, is talking about in the film is the presence of corn in nearly every processed food or drink that humans consume — including meats such as pork. And therefore, corn's signature is in the very chemistry of every American and any person in the world who consumes a modern diet of processed foods, many of which contain corn syrup.

The food we eat is stored as a sort of permanent signature in our hair. Two years ago, a couple of young film producers, Ian Cheney and Curt Ellis, approached Macko to have samples of their hair analyzed for the film. As they expected, Macko found that they had plenty of corn in their diet.

Macko is known for his wide-ranging research, including analysis of hair from ancient mummies of Egypt and Chile, Jamestown colonial residents, and the 5,200 year-old "Ice Man,” whose body was found preserved in the Oetztaler Alps. In each case, he was able to determine the diet of these peoples — some of whom never ate corn, or very little of it. But corn is ubiquitous in the American diet, and increasingly throughout the world. Other products, such as paper, often contain cornstarch, and corn is increasingly coming into use as a fuel source.

"King Corn" documents the journeys of the two filmmakers as they travel the United States from Macko's lab to the cornfields of the Midwest, to grain mills and processing plants, to the grocery stores and restaurants where corn-based products are sold. The film has screened in Washington, D.C., New York, Boston and Los Angeles. It is now available on DVD.