Lutein and Zeaxanthin for cognitive performance? Researchers have found macular pigment optical density to be correlated with cognitive performance in children.
Macular pigments lutein (L), zeaxanthin (Z) and meso-zeaxanthin have been found to be vital for retinal health. Studies have demonstrated that macular pigment optical density (MPOD) is a good indicator for lutein and zeaxanthin in brains of non-human primates and elderly humans.
Previous studies have demonstrated a positive correlation between MPOD and cognitive function in the elderly population. Given the higher concentration of lutein in the brains of infants than in adults (59 vs 34%), Barnett and coworkers conducted a study to determine the association of MPOD with academic performance in children.
Compared to serum levels of L and Z, MPOD is a stable biomarker of carotenoids in retina and hence a better representation of long term dietary intake of L and Z. The researchers assessed the relationship between MPOD, dietary L and Z, and academic achievement measured using Kaufman Test of Academic and Educational Achievement II (KTEA II), which included math, reading, reading fluency, written language, comprehensive achievement in preadolescent children (8-10 years of age). The result showed better performance on academic measures, specifically in math and written language, in children with greater MPOD values. In addition, the relationship between MPOD and academic measures were more consistent than that of cognitive performance and L and Z dietary intake.
The enhancement of cognitive function by L could be attributed to numerous mechanisms, such as neuroprotection of hippocampus from oxidative stress, increased lysophopholipids in frontal cortex and hippocampus or enhancement of gap junction communications, thus moderating the brain physiology to promote cognitive function in children.
Previous studies have highlighted the role of high quality diet rich in carotenoids, such as fruits and vegetables in enhancing cognitive performance in preadolescent children. Current study is congruent with previous studies, particularly assimilating the neuro-cognitive role of macular carotenoids, even after the adjustment of measures known to affect cognitive function in children, including IQ, sex, whole body fat percent and fat free mass maximal oxygen uptake (VO2).
Multiple studies have emphasized the role of L and Z in adult cognitive function. However, this study is one of the few studies that have featured the effect of dietary carotenoids, L and Z in cognitive performance of preadolescents. The increased cognitive performance in children will impact their future academics, health and quality of life. Furthermore, due to the absence of Daily Reference Intake (DRI) for L or Z, researchers have contributed to evidence base for consideration of L and Z as critical nutrients and their further recommendation in public health policy.
Barnett S, Khan N, Walk A, Raine L, Moulton C, Cohen N et al. Macular pigment optical density is positively associated with academic performance among preadolescent children. Nutritional Neuroscience. 2018;21(9):632-640.