Evaluating the Influence of Egg Consumption as a Source of Macular Carotenoids and the Impact on Serum Cholesterol Risk Ratios

Abstract

Abstract: : Purpose: To evaluate to effect of consuming one egg per day on serum and macular carotenoids, lutein and zeaxanthin, in healthy volunteers. Methods: Volunteers were screened for serum cholesterol (< 5.2 mmol/L) and macular pigment optical density (MPOD) (< 0.28) and were randomized to placebo (n=6) or 6 eggs/week (n=7) for 3 months. Eggs from local grocers were employed. Fasting blood was collected at baseline and on monthly visits. MPOD was determined by heterochromatic flicker photometry at baseline and twice monthly. Serum and egg yolk carotenoids were analyzed by reverse-phase HPLC and serum lipids were measured enzymatically on Roche COBAS analyzer. Results: Mean MPOD of the intervention group at baseline was was 0.179 (SD=0.073) and after 3 months of consuming 6 eggs/week was 0.289 (SD=0.077); this difference was significant (p<0.04). The MPOD of the placebo group at baseline was 0.173 (SD=0.091) and after 3 months was 0.196 (SD=0.084); this difference was not significant. Serum zeaxanthin in the intervention group increased from 29 µg/L (± 9) to 40 µg/L(±14) (p < 0.03); change in serum lutein in the intervention group was not significant. Serum lutein and zeaxanthin showed no significant change in the placebo group. Serum cholesterol increased to > 5.2 mM in 3 of the 7 subjects on egg intervention. Conclusions: Eggs serve as a bioavailable dietary source of macular carotenoids. While the average level of lutein and zeaxanthin in one egg yolk is modest (L=250 µg and Z=200 µg, for the eggs used in these studies) the bioavailability appears to be high. Consuming 6 eggs /week resulted in a significant increase in MPOD, but may in some individuals increase the serum cholesterol risk ratio. Support: Grant from The Egg Nutrition Center

Keywords: carotenoids/carotenoid binding proteins • macular pigment • antioxidants