Eating oily fish may cut risk of blindness

London: Eating fish once or twice a week may reduce the risk of age-related blindness by nearly a half, a new study has claimed.

Researchers at the Harvard Medical School found that eating oily fish such as tinned salmon and tuna – which are rich in omega-3 fatty acids – can help prevent the onset of age-related macular degeneration (AMD) that leads to the gradual loss of vision.

They found that having just one to two portions of fish a week could reduce the risk of sight loss by up to 42 per cent in older women. And this finding backs up previous research which showed similar results in men, the Telegraph reported.

The lead author Dr William Christen said that "dark meat" fish appeared to help the most.

He said: "This lower risk appeared to be due primarily to consumption of canned tuna fish and dark-meat fish."

AMD is caused by the deterioration and death of the cells in the macula, a part of the retina used to see straight ahead.

It is a major cause of visual impairment in people older than 55 years and affects more than 1.75 million in the US alone. The condition is more common among women, and is thought to be linked to smoking and heavy drinking.

To obtain the findings, the Harvard team piggybacked on a another study of more than 38,000 women who were AMD-free when the study was began.

Questionnaires were given out to assess participants eating habits, including how much omega-3 fatty acids each woman ate.

Over a 10-year follow-up period, the women`s eye-health was tracked, with a specific focus on AMD. A total of 235 of the women who participated developed AMD.

It was found that women who ate one or more servings of fish a week were 42 per cent less likely to develop the condition than those who ate less than one serving of fish per month.

Omega 3, whose common form in food is Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) can also be taken as a supplement, the researchers said.

"In summary, 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," they wrote.

For omega-6 fatty acids, higher intake of linoleic acid but not arachidonic acid was associated with an increased risk of age-related macular degeneration, however this association was non-significant after adjustment for other risk factors and fats.

The study was published in the journal Archives of Ophthalmology.