The study, published in Archives of Ophthalmology, reports that regular consumption of DHA, EPA, and fish is associated with up to a 45 percent lower risk of visual impairment due to AMD.
“These prospective data from a large population of women with no prior diagnosis of AMD indicate that regular consumption of DHA and EPA and fish significantly reduced the risk of incident AMD,” said the researchers, led by Dr William G. Christen of Brigham and Women's Hospital and Harvard Medical School, USA.
They added that the results of the study “appear to be the strongest evidence to date to support a role for omega-3 long-chain fatty acids in the primary prevention of AMD, and perhaps a reduction in the number of persons who ultimately have advanced AMD.”
Omega-3 for AMD
An estimated 9 million US adults over the age of 40 show signs of age-related macular degeneration (AMD). The most cases of severe vision loss associated with the disease are due to advanced AMD, which affects an estimated 1.7 million people.
“For the large majority of persons with early or no AMD, there is no recognized means of disease prevention …Thus, the identification of means to prevent or delay the development of AMD would have marked public health significance,” said the authors
Dietary intake of fish, specifically the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), has been linked with reduced rates of cardiovascular events in epidemiologic studies, and researchers have suggested similar benefits may be possible for AMD.
Omega-3 fatty acids are known to exert anti-inflammatory, anti-atherosclerotic, and antithrombotic effects on blood vessels and may help to maintain or improve blood flow in the eye.
“The further observations that DHA and arachidonic acid (AA), an omega-6 fatty acid, are found in high concentrations in the retina, are modifiable by diet, and are important structural components of retinal photoreceptor outer segments and vascular tissue further support the potential importance of these nutrients in AMD,” explained Christen and his colleagues.
The new report examined the relationship between dietary intake of DHA and EPA and fish with visually significant AMD over a ten year follow-up of a large group of female health professionals.
The researchers collected information on eating habits via questionnaire at the beginning of the study. The 38,022 women were then followed up over ten years to track the diagnosis of AMD.
Dr Christen and his co- workers reported that women who consumed the most DHA compared with women who consumed the lowest amount had a 38 percent lower risk of developing age-related macular degeneration, whilst higher intake of EPA resulted in a 35 percent lower risk.
Results for fish intake showed that consumption of one or more servings of fish per week, when compared to less than one per month, was associated with a 42 percent lower risk of AMD.
“This inverse association was independent of other AMD risk factors and was not materially altered after adjustment for saturated, monounsaturated, and trans unsaturated fat intake,” explained Christen and colleagues.
“Thus, these findings suggest that dietary intake of DHA and EPA and fish may be beneficial in the primary prevention of AMD,” they added.
The team of researchers concluded that their results “indicate that regular consumption of docosahexaenoic acid and eicosapentaenoic acid and fish was associated with a significantly decreased risk of incident AMD and may be of benefit in primary prevention of AMD.”
Source: Archives of Ophthalmology
Published online ahead of print, doi: 10.1001/archophthalmol.2011.34
“Dietary n-3Fatty Acid and Fish Intake and Incident Age-Related Macular Degeneration in Women”
Authors: W.G. Christen, D.A. Schaumberg, R.J. Glynn, J.E. Buring