In spite of the well-known damaging effects of the sun on our skin, many of us still perceive a tan as healthy-looking. But you don’t need to risk the health of your skin in the sun or a tanning bed to make it look healthy - the sun isn’t the only factor that can alter skin color.
Carotenoids are a group of 600 antioxidants including alpha-carotene, beta-carotene, lycopene, lutein, zeaxanthin, and astaxanthin. The richest sources of carotenoids are green, orange, and red vegetables and fruits. Many health-promoting phytochemicals, such as carotenoids, flavonoids, and phenols are pigment molecules that provide both attractive colors and health benefits. We are drawn to the vibrant colors of fresh produce that signal health benefits, and a new study has found that we can discern with our eyes how healthy the diet of a potential mate is.
Pigmentation in many species is perceived as a sign of health – birds for example. Carotenoids (both dietary and self-produced) are responsible for the bright feather colors of male birds, which make them more attractive to potential mates. There is evidence that in birds, dietary carotenoids do not merely serve this cosmetic purpose – increased carotenoid intake in birds may also improve color vision, sperm quality, and the health of offspring. 
One study investigated people’s perception of skin ‘lightness’ and ‘yellowness’ – yellowness is influenced by both carotenoids and melanin (melanin increases in response to sun exposure). Researchers asked subjects to choose from sets of photos of two different skin colors – one whose yellowness was due to melanin, and one due to carotenoids – which skin color appeared healthier. Subjects consistently chose carotenoid coloration over melanin coloration. 
According to first author of the paper Ian Stephen, “We found that, given the choice between skin colour caused by suntan and skin colour caused by carotenoids, people preferred the carotenoid skin colour, so if you want a healthier and more attractive skin colour, you are better off eating a healthy diet with plenty of fruit and vegetables than lying in the sun.” 
There is a direct relationship between skin appearance and health – if your skin does not have an orange tinge, then you are not on a healthy diet. You can even quantify your skin carotenoid levels, which reflect dietary carotenoid intake, using a specialized scanner. [4, 5] I use one of these scanners in my medical practice to confirm that phytochemicals have accumulated in the skin of patients, affording them protection against cancer and other chronic diseases. Plus these phytonutrients in the skin offer protection from sun damage, aging of the skin and skin cancer from sun exposure. 
So eating carotenoid-rich food is not only a path to excellent health – it’s also a way to look good!
1. Carotenoids Are Cornerstone of Bird's Vitality. ScienceDaily, 2009.
2. Stephen, I.D., Coetzee, V., Perrett, D.I., Carotenoid and melanin pigment coloration affect perceived human health. Evolution and Human Behavior, 2010.
3. Looking good on greens. Eurekalert!, 2011.
4. Ermakov, I.V. and W. Gellermann, Validation model for Raman based skin carotenoid detection. Arch Biochem Biophys, 2010. 504(1): p. 40-9.
5. Ermakov, I.V., et al., Resonance Raman detection of carotenoid antioxidants in living human tissue. J Biomed Opt, 2005. 10(6): p. 064028.
6. Nichols, J.A. and S.K. Katiyar, Skin photoprotection by natural polyphenols: anti-inflammatory, antioxidant and DNA repair mechanisms. Arch Dermatol Res, 2010. 302(2): p. 71-83.