New research suggests that eating egg yolks regularly may help cut the risk of age-related macular degeneration, a leading cause of vision loss in older Americans.
Eggs contain lutein and zeaxanthin, which are carotenoids in the macular region of the retina of the eye (macular pigment). Therefore, lutein has been studied for its use in treating cataracts, preventing macular degeneration and retinal degeneration. Lutein and zeaxanthin also have antioxidant capabilities as well as the ability to trap short-wavelength light.
In the study, 52 older adults (69 years old on average) who were taking statins were evaluated for four weeks. For the next five weeks they ate two eggs yolks daily. This was followed by a four-week washout period. Then, for the last five weeks, the participants ate four egg yolks daily.
The researchers found that luetin levels increased by 16 percent after the two-yolk phase and 24 percent after the four-yolk phase. Zeaxanthin increased by 36 percent after the two-yolk phase and 82 percent after the four-yolk phase.
Macular pigment optic density increased after both yolk phases among those who had low levels at the start of the study.
High-density lipoprotein (HDL) cholesterol levels, also called "good" cholesterol, increased during both phases of the study. The participants' low-density lipoprotein (LDL) cholesterol levels, triglyceride levels and total cholesterol levels remained the same throughout the study.
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1.Natural Standard: The Authority on Integrative Medicine. http://www.naturalstandard.com/
2.Vishwanathan R, Goodrow-Kotyla EF, Wooten BR, et al. Consumption of 2 and 4 egg yolks/d for 5 wk increases macular pigment concentrations in older adults with low macular pigment taking cholesterol-lowering statins. Am J Clin Nutr. 2009 Nov;90(5):1272-9.