You know eating fruit and vegetables is virtuous¹. But did you know it can also make you look good?

你知道吃水果和蔬菜有很多好处，但你可知道多吃水果蔬菜会让你变漂亮？

People who increased their intake² over just six weeks developed a healthy glow and appeared more attractive, researchers found.

Scientists at St Andrews University found eating them subtly increased yellow and red pigments³ in the volunteers' skin.

They monitored the food intake of 35 people and took pictures of their faces, arms and hands using a sensitive camera at the start, and after three and six weeks.

Increasing their intake of greens by 2.9 portions a day was found to make the person look more healthy and an extra 3.3 portions could enhance their attractiveness, when their photographs were rated by others.

Fruit and vegetables are rich in carotenoids, which are known to protect against cell damage from pollution and UV rays, and can also prevent age-related diseases including heart disease and cancer.

But while it was known eating extreme amounts of certain vegetables such as carrots could turn skin orange, it was not known a small increase was perceptible（可觉察的） to others - and was seen as appealing（吸引人的） .

A camera measured changes to the skin's redness, yellowness and lightness, and found it significantly changed in people who naturally increased their intake. These changes were not evident at three weeks.

Using light sensors⁴, the researchers showed these red and yellow hues⁵ were linked with the levels of carotenoids（类胡萝卜素） in their skin.

There are hundreds of carotenoids but those thought to have the most dramatic effect are lycopene - which gives tomatoes and red peppers their red colour - and beta-carotene found in carrots as well as broccoli⁶（西兰花） , squash（南瓜） , and spinach⁷（菠菜） .

Skin colour is also affected⁸ by chemicals called polyphenols （多酚） , found in apples, blueberries and cherries, which cause blood rush to the skin surface.