By Rob Winwood
A new, small Japanese study (n=20) has demonstrated that a six-month supplementation of 20 mg lutein, 1 mg zeaxanthin and 200 mg docosahexaenoic acid (DHA) dramatically increased blood serum levels of both carotenoids, resulting in higher levels of the protective pigments in the fovea of the eye as measured by macular pigment optical density (MPOD).
The xanthophylls lutein and zeaxanthin are potent antioxidants that are found in the macular pigment of the human eye. This macular pigment is particularly concentrated in the fovea, the central area of the retina where it can protect the retinal pigment epithelium from the effects of photooxidative stress and blue light (2). The fovea is close to the optic nerve and is important for central vision and visual acuity.
In the new study (1), 20 patients in Japan aged 56 years or more (average age 66 years) were selected as they had wet age-related macular degeneration (ARMD) in one eye but the other was healthy. ARMD is the leading cause of blindness in older people. Wet ARMD derives its name from the tiny, abnormal vessels that grow behind the retina toward the macula that seep fluid into the tissue leading to the onset of blindness. It gradually destroys the macula, the part of the eye that provides sharp, central vision needed for seeing objects clearly.
There is some evidence that lutein, zeaxanthin and DHA may prevent the progression of ARMD (3). Lutein and zeaxanthin can be obtained from the diet by consuming dark green, leafy, vegetables and egg yolks, while DHA, a marine-derived omega-3 fatty acid, can be obtained from oily fish. Alternatively, a variety of proprietary supplements contain all three. In the new study, the MPOD was determined by quantification of the fundus autofluorescence (FAF) using a confocal scanning laser ophthalmoscope.
The blood serum levels of lutein and zeaxanthin were determined at the start of the trial and again after three and six months. The intervention dramatically increased blood serum levels of both carotenoids, which in turn resulted in higher levels of the protective pigments in the fovea of the eye as measured by MPOD. The strongest association occurred when considering the pigment levels at the periphery of the fovea. This could be advantageous because normally the concentration of the xanthophylls reduces significantly at the edges of the macula in ARMD patients (4).