Why you may want to tuck in your veggies at night

A cabbage looper caterpillar feeding on spinach and carrots.
A cabbage looper caterpillar feeding on spinach and carrots.

By Casey Frye, CCNN Writer

Oh geez, I left my phone AND my watch at home, now I don’t know what time it is! I guess I should check my… salad? That is what Rice University meant when they said that vegetables are time-sensitive, right? Actually, they had something different in mind, which involves veggies bravely fighting bugs during the daytime and passing that healthy fighting power onto us! Let’s see how that’s done.

First things first: bugs. Typically, insects begin to eat vegetables a few hours before the Sun rises in the early morning. As a defense, the plants fend off those pesky, hungry vermin by producing anti-insect chemicals around that time.

Rice University scientists studied this phenomenon and found they could control the circadian rhythm of some vegetables. Circadian rhythm? Is that some kind of music? No, but I understand your confusion! A circadian rhythm is a type of ‘internal clock’ that is aligned with the time of day and is very sensitive to light. For instance, it is this circadian rhythm that helps your body rise in the morning and get sleepy around night. Nifty, huh?

Rice biologist Janet Braam is leading the study, and actually got the idea from her teenage son! See, she’d been telling him about how plants get stronger at certain times of the day and he said, “Well, I know what time of day I’ll eat my vegetables!” Braam explains, “That was my ‘aha!’ moment. He was thinking to avoid eating the vegetables when they would be accumulating the anti-insect chemicals, but I knew that some of those chemicals were known to be valuable metabolites for human health, so I decided to try and find out whether vegetables cycle those compounds based on circadian rhythms.”

Rice University researcher
Rice University undergraduate researcher Zhengji “Jim” Sheng tests the circadian clock defenses of lettuce with caterpillars.

Soon, they were shining light on cabbage to trick it into thinking it was morning time even when it wasn’t. This caused the cabbage to produce cancer-fighting antioxidants (little molecules that help our health) at specific times. Now, the next question was, how can they get the plants to pass this healthy punch on to us? After all, it’s not like people have little rooms where they can play tricks on cabbage at home. Well, it turns out that even after plants are harvested, they still have their circadian rhythm working just fine. So, rather than randomly storing vegetables in dark crates while they’re being shipped and keeping them under bright grocery store lights, Braam’s research sheds light – no pun intended – on ways to improve already nutritious veggies.

While this is unlikely to happen anytime soon, in the meanwhile, maybe you can tuck your veggies in at night.

Images and video courtesy of Rice University.