Many of the fruits and vegetables in your fridge may still be alive. Their biological clocks keep on ticking even after they have been picked, possibly affecting their nutritional value.
Plants have circadian rhythms just as we do. Our circadian rhythms help set the pace of various bodily systems. Plants are similar.
Researchers at Rice University had previously found the physiology of laboratory-grown plants changed over the course of a day in relation to the plants' circadian rhythms. Their circadian cycles enable them to alter levels of certain chemicals that keep bugs at bay and help them cope with the stresses of weather.
When cabbage was stored under 12-hour light-dark cycles, it provided two to three times more beneficial phytochemicals if eaten four to eight hours after the beginning of the light period than if the cabbage were stored under constant light or constant darkness. Comparable responses were found in lettuce, spinach, zucchini, sweet potatoes, carrots, and blueberries.
Cell metabolism in the leaves, branches, fruits, and roots of plants continued to react to light, meaning the cells remained essentially alive even after crops were harvested. The chemicals that remain active are the same ones touted to have an anti-cancer effect in humans when fruits and vegetables are eaten.
“Vegetables and fruits, even after harvest, can respond to light signals and consequently change their biology in ways that may affect health value and insect resistance, ” Janet Braam, Professor of Biochemistry and Cell Biology at Rice University said in a statement. “Perhaps we should be storing our vegetables and fruits under light-dark cycles and timing when to cook and eat them to enhance their health value. ”
The researchers made the discovery when studying cabbage. They found that when cabbage was stored under 12-hour light-dark cycles, it provided two to three times more phytochemicals if eaten four to eight hours after the beginning of the light period than if the cabbage were stored under constant light or constant darkness.
Comparable responses were found in lettuce, spinach, zucchini, sweet potatoes, carrots, and blueberries. The response is the same as the way that light-dark cycles in the field trigger cell metabolism to lessen damage to fruits and vegetables from insects.
The findings bring up some interesting questions to be answered by further research. Should we consider our foods’ daily schedules when deciding what to eat and when to have dinner? Should crops be harvested and preserved at certain times of the day to optimize their nutritional and phytochemical components?
The study is published in Current Biology.