Abstract
Objectives
Zeaxanthin (Z) and lutein (L) are xanthophyll carotenoids that function in part as macular pigments. Goji berries (Lycium Barbarum) are rich in zeaxanthin, and contain lutein, β-carotene, and β-cryptoxanthin. High intakes of Z and L have been associated with reduced risk of age-related macular degeneration. We assessed the impact of 3 months of 5 times per week intake of 28 g goji berry (GB), or a supplement providing 4 mg of Z and 6 mg of L (ZL) on macular pigment optical density (MPOD) and skin carotenoids (SC) in healthy adults aged 45–65 y old.
Methods
A randomized, open-labeled, parallel-arm pilot study was conducted at UC Davis. Study visits at baseline (SV1), and at 45 d (SV2) and 90 d (SV3) used heterochromatic flicker photometry to measure MPOD at 0.25, 0.5, 1, and 1.75 retinal eccentricities (RE), and Raman spectroscopy for SC. Between group changes within each treatment group were assessed with one-way Repeated Measures ANOVA with the Holm-Sidak post-hoc method.
Results
To date, 6 males and 13 females have been assessed. SC was not significantly different between the groups at SV1. The GB group showed a significant increase in SC at 45 d and 90 d compared to baseline (350.6 ± 138.4 SV1 vs. 400.6 ± 131.5 SV2 vs. 409.6 ± 156.6 SV3, P < 0.001, n = 11). No significant changes in SC were found in the ZL group (P = 0.2, n = 8). MPOD did not differ between any RE at any time point for either group. MPOD was positively and significantly correlated (Pearson's or Spearman's correlation) with SC at 0.25 (r = 0.49, P = 0.004), 0.5 (rho = 0.48, P = 0.005) and 1 (rho = 0.45, P = 0.008) RE in the GB group. SC was also significantly correlated with MPOD in the ZL group at 0.25 (rho = 0.43, P = 0.038) and 1 (r = 0.41, P = 0.047) RE.
Conclusions
We report preliminary results that goji berry intake increases skin carotenoids. These data confirm that Raman spectroscopy is a useful tool for the relationship of skin carotenoids with dietary carotenoid intake, as well as changes in skin carotenoids with macular pigment optical density.
Funding Sources
UC Davis, Department of Nutrition.
Macular pigment optical density measurements: evaluation of a device using heterochromatic flicker photometry
