A latest University of Colorado study found that exposing leafy plants that are grown in spacecrafts to few bright pulses of light daily increases the levels of eye-protecting nutrients, known as carotenoids.

Researchers said that long duration space travel exposes astronauts to eye-damaging radiation. To prevent any serious damages to their eyes, they should eat plants that contain zeaxanthin (a form of cartenoid), known to enhance eye health. Although Zeaxanthin can be taken through supplements, astronauts will acquire the true benefits of the nutrient when consumed through whole foods like green leafy vegetables.

NASA has been long researching ways to cultivate fresh produce during space missions to preserve crew confidence and improve overall nutrition.

"There is a trade-off," Barbara Demmig-Adams, professor of distinction in the Department of Ecology and Evolutionary Biology and a co-author of the study, said in a statement. "When we pamper plants in the field, they produce a lot of biomass but they aren't very nutritious. If they have to fend for themselves-if they have to defend themselves against pathogens or if there's a little bit of physical stress in the environment-plants make defense compounds that help them survive. And those are the antioxidants that we need."

Researchers said that zeaxanthin is produced when leaves are absorbing more sunlight than they need. The production of the nutrients is more likely to happen when the plants are physiologically stressed. For example, in order to prevent excess sunlight from damaging the plant's biochemical pathways, it produces zeaxanthin, a compound that helps to safely eliminate surplus light.

For the study, the researchers used the model plant species Arabidopsis. They found that when plants were exposed to few pulses of bright light daily, they started producing zeaxanthin in anticipation of excess sunlight. The pulses were short enough that didn't affect the optimal growing conditions, but long enough to spur the production of zeaxanthin.

Zeaxanthin, which the human body cannot generate on its own, plays a vital role in protecting eyes.

"Our eyes are like a leaf-they are both about collecting light," Demmig-Adams said. "We need the same protection to keep us safe from intense light."

The finding is published in the journal Acta Astronautica.