Abstract
Abstract: :
Purpose: To compare macular response to Lutein (LT) or Zeaxanthin (ZX) when ingested in equal doses utilizing equivalent formulations and to measure interactions of LT or ZX with serum concentrations of other fat soluble nutrients. Methods: Informed consent was obtained from 15 healthy subjects (ages 24-62), who were randomly assigned to ingest LT or ZX for 6 months. Macular pigment optical density (MPOD) was measured by heterochromatic flicker photometry at baseline and again every 2-4 days. Serum samples were collected at regular intervals before and after supplementation and analyzed for carotenoids, retinoids and tocopherols by HPLC. Results: After 3 days supplementation, serum LT or ZX increased in all subjects (P<0.01). Serum ZX also increased in subjects supplementing with LT (P<0.0001). At 6 months, serum ZX concentration in ZX-supplemented subjects was equivalent to serum LT in the LT-supplemented subjects. Subjects supplementing with ZX also had significant increases in serum concentrations of lycopene (P<0.01), α-cryptoxanthin (P<0.0001), and ß-cryptoxanthin (P<0.01). Decreases in other fat-soluble vitamins were not observed at any time. Of 15 subjects, 7 (46.7%) responded with significant increases in MPOD. The change in MPOD was correlated with the total supplement consumed (r = 0.50; P<0.06). Increased MPOD was observed in 2 of 7 subjects (28.5%) on LT, and 5 of 8 subjects (62.5%) on ZX. Among the non-responders, 78% had initial MPODs that were above the mean value for all subjects. Further studies are needed to determine whether carotenoid redistribution can mask a positive response to supplementation. In 3 subjects, supplemented with either ZX or LT, final MPODs were slightly lower than baseline MPODs. No fundus changes were observed, and no adverse experiences were reported. Conclusion: LT and ZX do not compete with other fat-soluble nutrients, but may enhance their absorption from serum. Individuals with high baseline MPODs are less likely to demonstrate significant increases after supplementation. These data suggest MPOD should be monitored during supplementation.
Keywords: 462 macular pigment • 492 nutritional factors • 337 carotenoids/carotenoid binding proteins