Abstract
Purpose: :
Lutein and zeaxanthin cannot be synthesized de novo in mammals and are derived exclusively from the diet.The purpose of this study was to investigate the relationship between dietary, serum and macular levels of lutein (L) and zeaxanthin (Z).
Methods: :
A prospective study, within the context of a twin study of heritability, was carried out using 320 healthy female volunteers, (mean age 41 years). Macular pigment optical density (MPOD) was measured using heterochromatic flicker photometry [HFP], a psychophysical method.Average daily dietary L and Z intake (mg/day) was evaluated using a validated food frequency questionnaire, developed by the Scottish Collaborative Group (subjects were asked to recall their average food consumption over the preceding 3 months).Blood samples were obtained on the same day as MPOD was measured. Serum carotenoid levels were measured using reverse phase high performance liquid chromatography.
Results: :
The mean dietary consumption of L and Z was 1.55mg/day (SD 0.14) and 0.89mg/day (SD 0.14), respectively. Mean MPOD was 0.44 (SD 0.214). Mean serum L and Z levels were 0.13µg/ml (SD 0.06) and 0.03µg/ml (SD0.02) respectively. Using regression analysis, although higher dietary lutein was significantly related to higher serum lutein levels (β=0.01, t=3.33, p=0.001, 95% CI 0.004-0.017) it only explained 5% of the variability in the serum variation. Similarly, higher dietary zeaxanthin was significantly related to higher serum levels (β =0.033, t=2.77, p=0.006, 95% CI 0.01-0.06).Although, there was a suggestion of a positive trend, with higher serum L associated with higher MPOD levels (β =0.58, t=1.97, p=0.05), no such relationship existed for serum Z (p= 0.526). Furthermore, no relationship was found between MPOD and dietary consumption of L or Z.
Conclusions: :
In this study, there is a weak but significant positive relationship between dietary L/Z and serum L/Z. Although a positive trend was found between serum levels and MPOD, this did not reach statistical significance. No relationship was found between dietary L/Z and macular pigment levels.
Keywords: macular pigment