Egg yolk consumption is associated with a decreased risk of age-related macular degeneration

This study was published in the American Journal of Clinical Nutrition 2009 Nov;90(5):1272-9

Study title and authors:
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.

Vishwanathan R, Goodrow-Kotyla EF, Wooten BR, Wilson TA, Nicolosi RJ.
Department of Clinical Laboratory and Nutritional Sciences, Center for Health and Disease Research, University of Massachusetts Lowell, Lowell, MA 01854-5125, USA.

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/19759170

The carotenoids of the macular pigment, lutein and zeaxanthin, may reduce the risk of dry, age-related macular degeneration, see here, and light induced retinal damage.

Macular pigment optical density is the thickness or density of the macular pigment. Research has shown that a low macular pigment optical density is a key risk factor for age-related macular degeneration, see here, while a high macular pigment optical density not only reduces one’s risk for but also helps to improve visual performance.

Low levels of high density lipoprotein (HDL) cholesterol are associated with an increased risk of age-related macular degeneration see here.

The study evaluated the levels of lutein, zeaxanthin, macular pigment optical density and HDL cholesterol in 52 adults, aged 60 and over, after the consumption for five weeks of either (i) two egg yolks per day (ii) four egg yolks per day. 

The study found:
(a) Lutein levels increased by 15.4% after consumption of two egg yolks per day, and increased by 28.4% after consumption of four egg yolks per day.
(b) Zeaxanthin levels increased by 36.3% after consumption of two egg yolks per day, and increased by 81.8% after consumption of four egg yolks per day.
(c) Macular pigment optical density levels increased by 3.9% after consumption of two egg yolks per day, and increased by 24.4% after consumption of four egg yolks per day.
(d) High density lipoprotein (HDL) cholesterol levels increased by 5.4% after consumption of both two and four egg yolks per day.

The results from the study suggest that egg yolk consumption is associated with a decreased risk of age-related macular degeneration.