Eating fish protects from blindness: Study

By Dr. Ananya Mandal, MDMar 17 2011

According to latest study fish that is rich in omega 3 fatty acids significantly lowers the risk of developing age-related macular degeneration (AMD) that leads to blindness. The study was published in the Archives of Ophthalmology.

The results come from the Harvard Women’s Health Study, which followed 39,876 women in midlife, had participants fill out detailed food-frequency questionnaires at the start of the study in 1993. After an average 10 years of follow-up, 235 of the women had developed macular degeneration, a progressive eye disease that is the leading cause of irreversible vision loss in the elderly. The team of researchers analyzed the data and found that women who had reported eating one or more servings of fish per week were 42 percent less likely to develop age-related macular degeneration than those who ate less than a serving each month. This was after they adjusted for factors that were linked to the disease like smoking and heredity. Eating canned tuna and dark-meat fish like mackerel, salmon, sardines, bluefish and swordfish appeared to have the most benefit.

“We know that inflammatory processes are involved in AMD, and the omega-3 long-chain fatty acids do have an anti-inflammatory effect,” said the lead author, Dr. William G. Christen, an associate professor at Brigham and Women’s Hospital and Harvard Medical School. He added, “Our observational data needs to be confirmed in randomized trials… But already the message seems to be simple and strong…Fish oil, that is the omega-3 fatty acids found in fish, that have long been thought to be protective against cardiovascular disease may also be of significant benefit in the primary prevention of AMD among women who have no disease or have undetected early signs of disease, and have not yet been diagnosed with AMD.”

About 9 million U.S. adults over the age of 40 have experienced some degree of AMD. Most have an early-stage form of the disease, while about 1.7 million have the advanced stage of illness that results in a serious loss of vision. To date, there is no recognized method, aside from advising patients not to smoke cigarettes, to prevent or slow the onset of AMD among those who do not have the disease or only display the symptoms of early illness.

Dr. David M. Kleinman, an associate professor and retina specialist with the Flaum Eye Institute at the University of Rochester in Rochester, N.Y., described the findings as “unsurprising, but very helpful.” “All scientists are going to say they need more research,” he noted. “But this is great data, and it's supportive enough for me to already say to my patients, 'Eat fish. Or almonds.' Because realistically, we're talking about an intervention that has very little risk, and is something that we believe is really good for the eye.”