FROM THE DESK OF:

The Surgeon General C Everitt Koop

NEW YORK -- Chalk up another possible health benefit of eating fish: prevention of age-related macular degeneration, the leading cause of irreversible blindness in the United States, according to a report. The macula is the central portion of the retina in the eye and when it is damaged, visual problems -- including blindness -- are the unfortunate result. In a study that enrolled more than 3,500 adults aged 49 and older, Dr. Wayne Smith of the Australian National University in Australian Capital Territory and colleagues found that more frequent consumption of Fish appeared to protect against late age-related macular degeneration. Their report is published in the March issue of Archives of Ophthalmology.

However, great intake of fish was necessary for the protective effect. Those who ate fish one to three times a month had about half the risk of late-stage disease than those who ate fish less than once a month. More fish was not necessarily better, the authors explain. The greatest amount of protection was seen in those who ate one serving of fish a week, and there was no additional benefit of consuming more.

The investigators note that eating too much fish may interfere with the absorption of vitamin E in the elderly. "Consumption of high-fish diets by the elderly has been shown to compromise the status of vitamin E, an important antioxidant needed by the retina;" they write, "this could explain the threshold protective effect from dietary fish."

The researchers point out that omega-3 fatty acids are found in the human retina. Since fatty fish also contain these compounds, Smith's team theorized that people who ate more fish might enjoy a reduced risk the eye disease. However, Smith's team did not see any benefit of fish consumption when it came to preventing the early stages of age-related macular degeneration, according to the report. The study did find that those who consumed low levels of saturated fat had a much lower risk of the eye disease -- either late- or early-stage -- than those who consumed the highest amounts.

Those findings agree with previous studies that have suggested, but not yet confirmed, that a high-fat diet may contribute to the illness. The cause of the eye disease is unknown, but several factors, including smoking, are known to increase risk of the disorder.

Because previous studies did not find any benefit of fish intake on age-related macular degeneration, more study is needed to confirm the findings. "Identifying preventable risk factors for age-related macular degeneration, now the most common cause of blindness in western countries, may be the only way of reducing the burden of this disease, as current treatments are rarely effective in the longer term," Smith and colleagues conclude.