Jilcott Pitts SB, Jahns L, Wu Q, Moran NE, Bell RA, Truesdale KP, Laska MN. A non-invasive assessment of skin carotenoid status through reflection spectroscopy is a feasible, reliable and potentially valid measure of fruit and vegetable consumption in a diverse community sample. Public Health Nutr. 2018 06; 21(9):1664-1670.