It’s August, and we’re in the midst of corn season. It’s easy to take these sweet, juicy kernels for granted, especially when the average American diet doesn’t fully depend on it. However, corn (also known as maize) provides 21% of human nutrition around the world. It hasn’t always been this way – the crop has taken a long and very interesting journey to get to where it is today. Corn started its evolutionary journey as a wild plant called teosinte, which has seven to twelve hard seed-like components, is very hard to eat, and is very low in nutrition. 

It also looks nothing like the corn we eat today:

Teosinte (left), the original wild ancestor of corn (right)

So how did this happen? The answer is us: people facilitated this evolution, and it wouldn’t have happened otherwise. Nina V. Federoff, a Penn State geneticist, is quoted in the book 1491: “To get corn out of teosinte is so – you couldn’t get a grant to do that now, because it would sound so crazy. Somebody who did that today would get a Nobel Prize!” And yet, the people responsible for this genetic transition are not Nobel Prize winners – they are the native people of southern Mexico, where maize was born.

Maize is often referred to as the domesticated form of teosinte, but that makes it sound as if the process was easy. The pioneering agronomists of southern Mexico started “domesticating” teosinte around 9,000 years ago, with the oldest physical evidence of maize production being a stone tool used to grind maize dating back 8,700 years. The plant slowly changed through a process called artificial selection, in which people, not nature, chose which individual organisms were able to produce offspring, and with whom. If they saw a particular individual that they liked, whether they enjoyed the taste of the corn or the size of the ear or any other characteristic, they would breed it with another favorable individual. In this way, what once was teosinte became bigger, tastier, and more nutritious.

Maize is still grown in southern Mexico, an area that is extremely diverse geographically and culturally, with many different indigenous groups and many different ecosystems within the same region. You can still visit this area and find authentic mom-and-pop tortilla shops and traditional maize farmers, growing a spectacular variety of red, yellow, blue, pink, and multicolored maize.

This image gives us a sense for the amazing variety of maize.
A few different varieties of maize.

We still don’t know exactly how teosinte became maize. Yes, it was most definitely the work of people practicing artificial selection over thousands of years, but this was a truly incredible feat, and one that changed the course of human history forever. The people of southern Mexico turned something practically inedible into something nutritious and healthy. When Columbus arrived in the Americas in 1492 and brought back maize to Europe, it became a world-wide hit, and many people around the world still rely on corn as their main source of nutrition.

And yet, something has happened to corn in modern times. In 1779, George Washington began the ‘scorched-earth campaign’ against the Iroquois nation. As soldiers began destroying homes and burning crops, one group stumbled upon a field of very sweet yellow corn. They had a taste, brought it home, and the rest is history. Our main eating corn in the United States is sweet corn, descended from the soldiers’ find. And while sweet corn is inarguably delicious, it has 1.5% of the nutritional value of original blue maize. As it turns out, by favoring the sweeter and tastier varieties of maize, we’ve been dramatically reducing its nutritional value:

By taking the sweet corn variety and running with it, breeding sugar into the crop and nutrition out of it, we’re now missing out on important nutrients like anthocyanins and beta-carotene. The original multicolored maize is now only sold by a few farmers in the U.S., mostly for decorational purposes.

In my last post about gleaning corn, which you can read here, I talked about the many environmental impacts posed by corn, including the relationship between the corn industry and the meat industry. This comes in the form of field corn, which covers all varieties of maize not used directly for human consumption. Some of it is fed to cows and other livestock, some of it is made into ethanol, and the rest is used to make food products like cornmeal.

Field corn that is fed to animals is called feed corn – confusing, I know. From a distance, feed corn doesn’t look that different from sweet corn:

But if you tried to eat feed corn, you would spit out the hard, brittle, basically tasteless kernels out right away. The real problem comes from the fact that feed corn is used to feed so many livestock in this country. Cows, pigs, sheep, etc. are not meant to eat corn, and they can’t digest it very well, so in many factory farm operations, they are pumped with antibiotics instead. Which, as you might imagine, is not good for the people that eat that meat. You are what you eat, and also what the thing you eat once ate. Check out this research paper if you are interested in this topic.

So what now? What can we do in our everyday lives to use the evolution of corn to our advantage?

(1) If you are interested in buying more nutritious corn, aim for corn varieties that are a deeper yellow instead of white.

(2) Make sure that you buy grass-fed beef to avoid the potential negative health impacts of corn-fed beef.

(3) Learn how to make maize tortillas with lime like the experts in southern Mexico do. Here’s a recipe that teaches you how.

*Cover photo from: