Abstract
Purpose: :
There is increasing evidence that suggests a possible beneficial effect of lutein supplementation on macular degeneration. Eggs, containing ample amounts of cholesterol, present themselves as a suitable vehicle to attain adequate absorption. We here present the results of a trial on the effect of HDL-cholesterol in daily egg consumption on macular pigment optical density (MPOD).
Methods: :
For this double blinded, interventional trial, 100 healthy subjects were recruited and randomized into 5 groups, stratified for age and gender and followed for three months. Group 1 consumed a normal egg, group 2 a lutein-enriched egg beverage, and group 3 had a lutein-enriched egg daily. Group 4 received a zeaxanthin-enriched egg, while the control group, group 5 received no product. Both these groups were not blinded. Serum lutein and MPOD was measured at baseline, week 6-7 and at endpoint. MPOD was obtained psychophysically by heterochromatic flicker photometry using the macular pigment screener (Tinsley Ophthalmic Instruments, Redhill, Surrey).
Results: :
Baseline characteristics were comparable in the five groups. A mixed model analysis with plasma lutein level as dependent variable, with diet as factor and with HDL-cholesterol, LDL-cholesterol, week and the interaction between week and diet as covariates showed a significant effect for diet (β=74.3 for the lutein egg; p=0.047), week (β=2.3; p<0.001), HDL-cholesterol (β=112.4; p<0.001), LDL-cholesterol (β=22.1; p<0.004), and the interaction term diet*week (β=10.0 for the lutein beverage and β=13.0 for the lutein egg; p<0.001). A mixed model analysis with MPOD as dependent and with week, lutein plasma levels, HDL-cholesterol plasma levels, LDL-cholesterol plasma levels, and the interaction between those three as covariates showed a significant effect of week (β= -0.006; p<0.001), HDL-cholesterol (β=-0.06; p=0.011), LDL-cholesterol (β=-0.025; p=0.014) and the interaction term lutein*HDL*week (β=1.1x10-5; p<0.001) on MPOD.
Conclusions: :
These results suggest that it is not only lutein supplementation that is required in order to increase MPOD, but also that HDL-cholesterol plays an intricate part in the delivery of this xanthophyll to the retina.
Clinical Trial: :
http://www.clinicaltrials.gov NCT00527553
Keywords: macular pigment • lipids • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials