A: There’s a simple scientific explanation for the plate-to-poop journey of that corn kernel you gnawed off of a cob or scooped off your plate. To understand it, though, you need to grow your corn knowledge.
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Corn kernels are actually seeds. The interior of the kernel holds the germ, or corn embryo. The germ is surrounded by a starchy food supply (endosperm) that feeds the seed after it germinates.
This is tasty and nutritious stuff, both for humans and billions of insects looking for a field snack.
That brings us to the kernel’s protective hull, or shell. The highlight of this outer layer is a waxy coating of cellulose. The bonds connecting cellulose molecules are very strong, creating what amounts to a survival defense shield.
How tough is that fibrous shell of cellulose? Well, it’s tough enough to withstand the rigors of the human digestive system. That’s why the casing of the corn kernel passes through your system looking fully intact.
If you find the reappearance of corn after a meal a bit unappetizing, there is a solution: chew more. Grinding corn between your teeth helps break down the outer casing of the kernel and reduce the colorful additions to bowel movements.
One more fact, too, as sweet corn starts popping up at markets: The average ear of corn includes about 800 kernels. That’s a lot of opportunity for pops of color in your poop after eating corn on the cob.
— Dietitian Beth Czerwony, MS, RD, CSOWM, LD.