Age related macular degeneration (AMD) is currently the leading cause of blindness. Certain dietary nutrients have been found to help prevent or slow the development of this disorder, including lutein and the omega-3 fatty acid DHA. Lutein and its structural isomer zeaxanthin accumulate in the retina, particularly in the macular region where they are components of macular pigment. Lutein is an antioxidant and filters blue light, protecting the macula from oxidative damage which contributes to AMD. DHA is also found in the retina, particularly in the photoreceptor outer segments which are constantly being renewed, requiring a steady supply of DHA for optimal retinal function. Previous studies have found that DHA intake is inversely related to the risk of AMD.
A new study from the American Journal of Clinical Nutrition (Johnson et al. 2008;87:1521-9) tested the effects of lutein and DHA on macular pigment optical density (MPOD). 49 women between the ages of 60 and 80 were randomly assigned to be given DHA, lutein, a combination of both, or a placebo for 4 months. At the end of the study, it was found that the spacial pattern of increases in MPOD varied depending on the supplement. Women given lutein had increased MPOD at each retinal locus and women given DHA had an increase in the most central locus. Serum concentrations of lipoprotein subfractions were also changed. Women supplemented with DHA tended to have increases in their high-density lipoprotein subfractions (HDL, or good cholesterol) while decreasing their low-density lipoprotein subfractions (LDL, or bad cholesterol). This was especially noticeable in the lutein + DHA group.
The study concluded that lutein and DHA may be helpful in the prevention of AMD. DHA’s effects are likely due to its influence on lipoprotein balance. Lutein is transported to the retina mainly by HDL, so DHA may help to accumulate lutein in the macula. These changes in lipoprotein balance are also related to a lower risk of cardiovascular disease, which shares many of the same risk factors as AMD.
For more information see Lutein and Omega Cardio
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