It’s not exactly earth-shattering news that fruits and vegetables are good for you, but the truth is, many of us (you know who you are) still don’t eat as healthy as we should. Now, scientists are tapping into our vanity to urge us to eat better.

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Here’s the deal:

The pigments that make apples red and carrots orange—called carotenoids—are an integral part of the body’s immune system and help us fight against aging and other kinds of damage. Doctors and nutritionists place such emphasis on eating fruits and vegetables because, like other animals, our bodies can’t produce these healthy antioxidants.

But they do store them, especially in our skin. The outer most layer of skin—the stratum corneum—is especially good at absorbing carotenoids. Ian Stephen, Ph.D., assistant professor of psychology at the University of Nottingham in England, pioneered the research connecting dietary carotenoids to the appearance of health. “Many bird and fish species have colorful ornaments,” he explained. “These patches are biggest and brightest in the healthiest individuals; it is carotenoids that give these ornaments their bright color.”

Stephen and his team wondered if carotenoids might make people look healthier, too, so they used a computer program to test people’s skin color preferences by allowing them to play with the hues of a person’s face. When asked to make the face look the healthiest, people using this program chose to increase the carotenoid content of the skin over other alteration options.

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But Ross Whitehead, Ph.D. candidate at the University of Saint Andrews in Scotland and lead author of new research published in PLoS ONE on the affect of diet on appearance, and his colleagues wanted to know just how small a shift in diet is required to see that healthy carotenoid glow. They followed 35 college students for six weeks, keeping tabs on their diet as well as measuring the color of their skin.

The subjects who, on their own, chose to eat more fruits and vegetables showed increased carotenoid pigmentation, leading to yellower and redder skin. “Around three portions over a six-week period is sufficient to convey perceptible improvements in the apparent healthiness and attractiveness of facial skin,” says Whitehead. Those who cut their carotenoid intake, however, paid the price and became much paler and appeared less healthy.

But donning a healthy-looking complexion is not just about eating fruits and vegetables. Carotenoids travel through and are stored in our bodies with the help of fats. A 2005 study found that pairing carotenoid-rich foods with avocados or avocado oil, which are high in unsaturated fats, improved absorption. “It is important to eat produce in conjunction with a balanced diet—for health reasons, but also to stand the best chance of receiving the skin color benefits,” says Whitehead.In the future, Whitehead hopes this kind of discovery will motivate people to eat better. And what better reason to pounce on fresh produce than to help you nab a more beautiful, glowing complexion?

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