Having a "healthy glow" may make you more attractive—if you're a white guy.
Beta-carotene is a pigment found in orange foods like carrots and sweet potatoes but also in greens like spinach and kale. It's part of a family of red and yellow plant pigments known as carotenoids, which act as antioxidants and can give the skin a golden hue.
Existing research suggests that carotenoid color affects mate selection in animals and other studies have shown that humans prefer faces that have been manipulated to have higher levels of carotenoid color. Surprisingly, people find carotenoid coloration more attractive than melanin coloration from sun exposure. It's thought that having a carotenoid-induced glow implies the subject eats well and is in good health—making them a solid mate from an evolutionary standpoint because they can probably pass on their genes. This theory, called the carotenoid trade-off hypothesis, suggests that only very healthy people enjoy an appearance boost from carotenoids because they've gotten more than enough from food. Those who don't get as much need all of their antioxidants for their original purpose and they don't make it to the skin.
Animal biology researchers at the University of Western Australia wanted to see if supplementation with beta-carotene would make men's faces more attractive to women, and test the idea that orange-tinted skin is really a sign of good health. Other studies done on supplementation and skin color were small and didn't include placebo-controlled groups, nor did they look at supplementation's effects on perceived attractiveness, perceived health, and actual health.
For this new study, they recruited 43 white men (average age: 21) to take 30,000 IUs of beta-carotene daily for 12 weeks while another 20 took a placebo. All of the guys had photographs taken before and after the study period and researchers measured three health markers as well: semen quality, immune function, and levels of oxidative stress. Next, they had 66 straight white women (average age: 33) view the before-and-after photos side by side and vote which one they found more attractive and healthier.
The guys who took the supplements did indeed have more yellow and red pigments in their skin after 12 weeks, and the women were 50 percent more likely to rate the beta-carotene faces as attractive and healthy-looking compared to both the before photos or the control group. Their health markers didn't significantly change, but perhaps that's because they took pills instead of eating actual produce, which contains other goodness like vitamins and fiber. (For the record, the guys in the study took a LOT of beta-carotene. The Recommended Dietary Allowance for men is 6,000 IUs from a supplement and 18,000 IUs from food and, for women, 4,667 IUs from a supplement and 14,000 IUs from food). The study didn't assess whether beta-carotene affected the attractiveness of women and while it didn't include men of color, other studies have shown that yellow undertones predicted which black men's faces would be most attractive to black women.
In sum, the finding is just another reason to eat your veggies—and use the yellow-y filters on Instagram that stop just shy of jaundice.