by Marion Nestle
Nov 11 2008

Corn is in everything!

Investigators at the University of Hawaii have just analyzed nearly 500 samples of fast food for their content of stable isotopes of carbon and nitrogen.  These are not radioactive but do indicate whether a plant conducts its photosynthesis through what is called a C3 or C4 metabolic pathway.  Corn is a C4 crop.  The analysis shows that virtually all of the meat came from animals raised on corn.  The potatoes were typically fried in corn oil.  Corn, say the investigators, is the basis of fast food.  And virtually all fast food is raised or prepared the same way. 

Didn’t we know that?  Yes, but the technology used in these experiments is clever.  Michael Pollan discussed this kind of chemical evidence in Omnivore’s Dilemma. Although I do not think it was his intention, many readers came away with the idea that corn is poison.  It isn’t.   Corn is a perfectly reasonable food, especially when mixed with soybeans, and the mix works fine for fattening up cattle.  From the standpoint of nutrition and the environment, feeding cattle on grass would be ideal, but it may not always be practical. That’s why some forward thinking cattle producers are raising their animals on grass for as long as they can, and then doing a quick finish with corn and soybeans.

A more important issue may be corn subsidies. Cheap feed promotes industrial meat production, with all of its environmental and health implications.  CAFOs (confined animal feeding operations), as the Pew Commission said earlier this year, have truly dreadful effects on the environments of the communities in which they operate, are not healthy for animals, and overuse antibiotics, which affects human health.   Corn subsidies make CAFOs possible. 

We can argue about how much corn is OK, but I can’t think of any reason to exclude it from the diets of animals or humans.   Corn is a good source of calories and is about 10% protein.  Its oil is relatively unsaturated.  And high fructose corn sweeteners are an almost one-for-one substitute for sucrose. For humans in particular, fresh sweet corn in mid-summer is surely one of the great wonders of the universe.   As with so much else in nutrition, some corn is OK, but a lot may not be.


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  • Between Michael Pollan’s book and the movie King Corn, I did not suddenly feel corn was evil but rather that I had no idea how much corn I was consuming! Or how government subsidies create low cost fast food and a farmer’s pressure to use GEO crops. It’s a big lesson in politics, if not nutrition.

  • Are you not concerned about the balance between omega-3 and omega-6 fatty acids?

  • Marion,

    Thank you for continuing to offer up these little morsels of nutrition news and insight. Yours is a robust blog with consistent updates and a spirited voice.


    – Joher

  • Marmar

    From what I understand, a diversity of food is important for health, human and animal. When foods that appear to be quite different are actually corn based, we are not only deceiving our eyes, but our bodies. Of course there is nothing inherently wrong with corn, but like Michelle suggests, the awareness of knowing how homogenized our food intake actually is can help us make efforts to diversify it in a true way, not just by artificially making it into a different shape or color.

  • So corn is the best thing we can eat?

  • Philly

    Marion – forgive me for posting an article from The Mail (I’m aware it is a sensational rag), but this article caught my eye:

    your argument that corn is a good food is valid and sound only insofar as the corn itself goes. my concern is that we North Amcns eat most of our corn in the form of genetically modified crops. if these crops create a qualitatively different physiological response compared to old-fashioned hybrids (as this study suggests), we may have a bigger problem on our hands than empty calories and environmental degradation.

    are we putting our endocrine systems at risk with over-consumption of GMO corn?