Lutein and Age related Macular Degeneration (AMD)
Research has suggested a minimum of 6-10 mg per day of lutein is necessary to realize lutein’s health benefits. One such benefit is lutein’s role in eye health, specifically its role in reducing the risk of Age Related Macular Degeneration (AMD).**
AMD occurs when the fragile center of the retina–the macula–deteriorates from a lifetime of slow but steady damage. The macula is a small area of the retina responsible for central vision, and high visual acuity.1 Poor macular health can cause oxidative stress within the retina, leading to a loss of central vision.
According to AMD Alliance International dry AMD, the more common and milder form of AMD, accounts for 85% to 90% of all cases. It develops gradually over time and usually causes only mild loss of vision. One key identifier for AMD is the collection of small, round, white-yellow, fatty deposits called drusen in the central part of the retina. Drusen accumulate in the Retinal Pigment Epithelium (RPE) tissue beneath the macula and the macula thins and dries out. The amount of vision loss is related to the location and amount of macular thinning caused by the drusen. Sometimes abnormal new blood vessels form (wet AMD). It is therefore important for individuals with dry AMD to have their eyes examined regularly, because it may eventually develop into the wet form.
What AMD looks like as it progresses
Although the wet form of AMD accounts for only 10 – 15% of all AMD, the chance for severe sight loss is much greater. It is responsible for 90% of severe vision loss associated with AMD. Wet AMD is caused by the growth of abnormal blood vessels, or choroidal neovascularization (CNV), under the central part of the retina, the macula. These abnormal vessels leak fluid and blood into the tissue at the back of the eye, causing a blister to form in the retina. This progression leads to scar tissue, distortion and a loss of central vision. Wet AMD can rapidly damage the macula and result in a very quick loss of central vision.
Lutein and its related compound zeaxanthin are highly concentrated in the macula, providing a yellow color known as the macular pigment (MP).The macular pigment protects the macula from the damaging photo-oxidative effects of blue light.2
Of the 600 or so carotenoids present in nature, only a handful are present in human serum. Of those, nature has chosen only lutein and zeaxanthin to be present in the macula. These facts alone suggest that lutein plays a critical role in eye health.
There is a wealth of data available supporting a role for lutein in reducing the risk of AMD.** There are a number of observational studies showing the association between lutein intake, serum levels, macular pigment density (MPD), 3, 4, 5-7, 8 and AMD risk in humans.9, 10, 11, 12, 13, 14, 15
Controlled intervention studies in humans are needed to establish causality. In terms of eye health, more and more studies investigating the direct effect of dietary lutein and lutein supplementation on macular pigment density are now being published.
Researchers agree that it is the body of evidence that must be evaluated collectively in order to determine the merits of a given nutrient, and any conclusions based on a single study are premature. The body of evidence appears to support a beneficial role for lutein in eye health.**