Abstract
Purpose: :
Past data from our group has shown that increases in retinal lutein (L) and zeaxanthin (Z) is related to faster temporal processing. The mechanism for such a relation, however, is not clear. The high frequency portion of the temporal contrast sensitivity function (TCSF) is thought to be determined post-receptorally and long-wave stimuli were used (obviating an absorption effect). LZ are found throughout the visual system, however, and we postulated that the effects of L and Z might also be post-receptoral (L and Z are also the dominant carotenoids within the brain). To further examine these ideas, we measured L and Z within the serum and TCSF on a sample of young healthy subjects.
Methods: :
62 young, healthy participants (mean age = 22.4 ± 4.4) were assessed across two sessions. TCSF was measured in free view (through an artificial pupil) using a 1-degree, 660 nm test (with adjustable modulation depth) centered within a 10-degree 660 nm surround. Serum lutein (L) and zeaxanthin (Z) was quantified using HPLC.
Results: :
Average area under the TCSF curve was significantly related to total serum lutein and zeaxanthin (p< 0.01), total serum lutein (p<0.01) and serum zeaxanthin (p<0.05).
Conclusions: :
One of the more significant indicators of neural age-related loss and disease is reduced temporal processing speed. Our results suggest that the relation to the dietary carotenoids L and Z is quite robust persisting even when measured indirectly within serum. These baseline data are a part of an ongoing L and Z supplementation clinical trial.
Clinical Trial: :
http://www.clinicaltrials.gov NCT00909090
Keywords: macular pigment • carotenoids/carotenoid binding proteins