Plasma kinetics of zeaxanthin and 3'-dehydro-lutein after multiple oral doses of synthetic zeaxanthin.
BACKGROUND
Zeaxanthin is hypothesized to reduce the risk of age-related macular degeneration; however, kinetic information is limited.


OBJECTIVE
The objective was to investigate the plasma kinetics of synthetic zeaxanthin after repeated oral doses and to assess the possible influence of other carotenoids on plasma zeaxanthin concentrations.


METHODS
After a run-in of 3 d, 20 healthy volunteers assigned to 2 parallel dose groups received once daily oral doses of either 1 mg (1.76 micro mol) or 10 mg (17.6 micro mol) zeaxanthin for 42 d. Plasma concentration-time profiles on days 1 and 42, concentrations immediately before zeaxanthin intake during the dosing period, and concentrations after the last dose until day 76 were monitored.


RESULTS
all-E-Zeaxanthin concentrations increased from 0.048 +/- 0.026 micro mol/L at baseline to 0.20 +/- 0.07 and 0.92 +/- 0.28 micro mol/L with 1 and 10 mg zeaxanthin, respectively. The dose-normalized bioavailability of all-E-zeaxanthin after the10-mg dose was 40% lower (P < 0.001) than after the 1-mg dose. Other kinetic parameters did not differ significantly between groups. After 17 d of dosing, >90% of steady state concentrations were reached, which was compatible with an effective half-life for accumulation of 5 d. The terminal elimination half-life was 12 +/- 7 d (n = 20). The time course of plasma all-E-3-'dehydro-lutein concentrations resembled that of all-E-zeaxanthin. The data provided evidence that all-E-3-'dehydro-lutein was derived from all-E-zeaxanthin. Concentrations of other carotenoids were not affected. Zeaxanthin was well tolerated.


CONCLUSIONS
Long-term oral intake of 1 and 10 mg zeaxanthin as beadlets increases plasma zeaxanthin concentrations approximately 4- and 20-fold, respectively. Evidence that all-E-3-dehydro-lutein is formed from zeaxanthin was strong.
Department of Human Nutrition and Health, Roche Vitamins Ltd, Basel, Switzerland.
Dieter
D
Hartmann
Petra A
PA
Thürmann
Volker
V
Spitzer
Wolfgang
W
Schalch
Birke
B
Manner
William
W
Cohn
D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D014975:Lutein / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics*; D008268:Macular Degeneration / Q000097:blood / Q000517:prevention & control*; D008297:Male; D012307:Risk Factors; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood / Q000493:pharmacokinetics*
D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene; D014975:Lutein