Two Nutrients Improve Age-Related Macular Degeneration
Researchers found specific benefits of two nutrients for individuals who have age-related macular degeneration. People age 50 and older are most at risk of developing this eye disease, which can result in severely limited vision.
Macular degeneration is characterized by a deterioration and loss of central vision in one or both eyes. This occurs because of damage to the macula, a small, highly sensitive site near the center of the retina that has the highest concentration of cone cells in the eye, which are responsible for clear central vision.
Macular degeneration, lutein and zeaxanthin
The macula is yellow because it contains two nutrients, lutein and zeaxanthin, which are pigments known as carotenoids. Zeaxanthin is present in higher amounts in the macula while lutein is more prominent in the retina.
Both of these nutrients serve to absorb the excessive blue and ultraviolet light that enters the retina and are the only carotenoids capable of this essential function. When the layer of macular pigment is too thin, the damaging rays can damage the eye.
Individuals with age related macular degeneration may experience either a slow or rapid decline in central vision accompanied by blurriness, distortion, or dark areas. This vision loss makes it difficult to impossible to read, drive, use a computer, sew, or other activities that require central vision.
Studies of lutein and zeaxanthin
Previous research has indicated that lutein and zeaxanthin play an important role in age-related macular degeneration. In a 2013 review, for example, the authors noted that high dietary intake of lutein and zeaxanthin “have been associated with a lower risk of prevalence and incidence of AMD.”
In the new study, which appears in the British Journal of Ophthalmology, investigators randomly assigned 112 patients with early age-related macular degeneration to one of four groups: 10 mg lutein, 20 mg lutein, 10 mg lutein plus 10 mg zeaxanthin, or placebo daily for two years. Here’s what the investigators learned after two years:
- Lutein plus zeaxanthin significantly boosted macular pigment optical density (MPOD). The MPOD is the density or thickness of the macular pigment layer, which varies among individuals.
- Supplementation with either 10 mg or 20 mg lutein was associated with significant increases in mean retinal sensitivity (MRS), although the improvement was better in the 20-mg group. MRS refers to the sensitivity of the receptors in the retina to respond to light stimuli.
- Individuals in the placebo group did not experience any improvements in MPOD or MRS
Other nutrients and macular degeneration
Two National Eye Institute studies have been landmarks in the search for nutrients that may help with age-related macular degeneration. One is the Age-Related Eye Disease Study (AREDS), in which researchers concluded that the antioxidants beta-carotene, vitamins E and C, and the minerals copper and zinc, in a specific formulation, can be helpful in fighting macular degeneration.
In the AREDS2 study, the investigators evaluated the benefits of other nutrients found to be helpful. They include lutein, zeaxanthin, and the omega-3 fatty acids docosahexaenoic acid (DHA) and eiosapentaenoic acid (EPA).
The authors of the latest study concluded that taking supplements of lutein and/or zeaxanthin is beneficial for two important issues associated with early age-related macular degeneration. This finding, along with previous research, helps support the use of these two nutrients for macular degeneration.
Also read: Macular degeneration treatment options
Huang Y-M et al. Changes following supplementation with lutein and zeaxanthin in retinal function in eyes with early age-related macular degeneration: a randomized, double-blind, placebo-controlled trial. British Journal of Ophthalmology 2015; 99:371-75
Sin HP et al. Lifestyle modification, nutritional and vitamins supplements for age-related macular degeneration. Acta Ophthalmology 2013 Feb; 91(1): 6-11