Don't turn blind eye to eating fish

Put down those chips - while you can still see them!

Research in Boston has found that fat in your diet can increase the risk of going blind.

Doctors have long known that some fats in snack food such as potato crisps and chips, cookies and chocolate can cause heart disease.

But a new study warns that fat in your diet can also lead to age-related retina macular degeneration (the macula is an area of the retina in the back of the eye and macular degeneration is the leading cause of blindness in people aged 65 and over).

"Fats in our favourite snacks cause a two-fold increased risk of age-related macular degeneration," says researcher Johanna Seddon, an associate professor of opthalmology at Harvard Medical School.

Just as dietary fat can accumulate in the blood vessels and lead to heart disease, it can also clog up the vessels going to the eyes, leading to loss of vision.

There was no proven treatment for early and moderate forms of macular degeneration, and therapies for the advanced stages were limited, she said.

The study - the largest so far to look at the connection between dietary fat and the eye disease - involved more than 300 patients.

All were aged between 55 and 80, and all had advanced macular degeneration. Each person was sent a list of food and drink, both healthy and high-fat, and was asked to indicate how often each was consumed over a year.

People who ate more processed foods of any type daily - foods high in vegetable, monounsaturated, and polyunsaturated fats - were more likely to get the eye disease.

Those foods that were highest in a type of fat called linoleic acid (found primarily in snack foods like potato chips) seemed to put people at even higher risk.

People who ate fish high in omega-3 fatty acids were less likely to have the eye disease, Johanna Seddon said, but only if they also ate very little snack food containing linoleic acid.

Her previous studies on macular degeneration have shown that it does run in families, suggesting a genetic component.

"But part of it could be environmental as families share common eating habits."

Retina degeneration was a 30-year to 40-year process, and any dietary and lifestyle changes had to be made at an early age.

Johanna Seddon's advice: "Eat fish, not fat. Eat fish two or more times a week."

* The Seddon study appears in the Archives of Opthalmology.