Lutein and zeaxanthin in human milk independently and significantly differ among women from Japan, Mexico, and the United Kingdom

Human milk contains numerous dietary carotenoids, including lutein and zeaxanthin (L&Z). It has been proposed that L&Z are actively transported into milk as in the eye. Because L&Z help protect the retina from blue light damage, and infants are more susceptible to blue light damage than adults, it is important to understand milk L&Z as the sole dietary source for breast-fed infants. Unfortunately, the few studies that have measured human milk L&Z separately have involved small and demographically limited sample pools. This study measured L&Z in milk samples from 3 countries (Japan, Mexico, and the United Kingdom; n = 20 each) using a modified high-pressure liquid chromatography method. Mean L&Z concentrations in human milk differed among the 3 countries, with Japan having significantly more lutein than the United Kingdom (P < .001) and Mexico having significantly more zeaxanthin than the United Kingdom (P < .001). Lutein concentrations were correlated with zeaxanthin concentrations across the data set (r = 0.79, P < .001), but the slope differed by country. These findings do not appear to support that L&Z are actively transported into breast milk. However, further research is needed to understand how maternal diet ultimately influences infant eye concentrations.