General Health
Omega 3 fatty acids protect against eye disease
By Ben Wasserman-foodconsumer.org
Jun 30, 2007 - 5:31:57 PM

A new animal study suggests that omega-3 fatty acids found in a small number of foods such as oily fish, flaxseeds and walnuts may help protect against human retinopathy, a deterioration of the retina that could ultimately lead to blindness.

In contrast, high consumption of omega-6 fatty acids is associated with an increased risk of retinopathy, according to the study reported in the journal Nature Medicine.

Retinopathy, an eye disease affecting the retina - the light sensitive membrane at the back of the eye, occurs in about four million diabetic patients and about 40,000 premature infants in the United States.

In the study, Kip Connor from Harvard Medical School and John Paul SanGiovanni from the National Eye Institute studied in a mouse model the effect of omega 3 and omega 6 fatty acids on the disease.

They found that increased dietary intake of omega-3 and decreased intake of omega-6 fatty acids reduce the area of vessel loss that would ultimately cause the growth of the abnormal vessels and blindness.

The study was performed in mice that have been genetically modified to prevent the mice from converting omega-6 to omega 3 fatty acids.   The researchers fed mice diets rich either in omega 3 fatty acids or omega 6 fatty acids.

Animals on the diet rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), two commonly seen omega-3 fatty acids, had 40 to 50 percent less initial vessel loss in the retina than the mice on the omega 6 diet.

The researchers believe that omega 3 fatty acids suppress a type of inflammatory protein known as tumor necrosis factor alpha (TNF-alpha), which is found in cells called microglia.   TNF-alpha is linked with retinal blood vessels.

Anti-inflammatory compounds neuroprotectinD1, resolvinD1 and resolvinE1, which protect against pathological vessel growth, were produced in the retinas of mice on the omega 3 diet, but not in those on the omega 6 fatty acid diet, the study shows.

According to Nutraingredients.com, a human trial that aims to clarify the effect of omega 3 fatty acids on human retinopathy is scheduled to be carried out in premature infants who are at high risk of becoming blind because of the eye disease.

The ratio of omega 6 fatty acids to omega 3 fatty acids in the American diet is ridiculously high, about 16 to 20, which experts have been saying can cause health problems. Omega 6 fatty acids are widely present in vegetable oils, which is commonly used in the West.