Contrary to some past studies, new research suggests that intake of fatty acids found in fish may help prevent age-related maculopathy, a deterioration of the eye's retina that can lead to blindness.
|A chef prepares a salmon in the kitchen|
Several studies in recent years have found a link between high fat intake -- from any source -- and a higher risk of age-related maculopathy (ARM), the leading cause of vision loss among the elderly.
The findings are puzzling because unsaturated fats from fish and plant sources like olive oil are widely recognized as healthy fats that may protect against heart disease and other ills.
The new study, published in the Archives of Ophthalmology, adds to the puzzle. Australian researchers who followed more than 3,600 older adults for five years found no evidence that dietary fat, of any kind, increased the risk of ARM.
What's more, men and women who ate the most omega-3 fatty acids had a lower risk of ARM than those with the lowest intakes. Omega-3 polyunsaturated fats are found largely in oily fish, and to a lesser extent in flaxseed, walnuts and soybeans.
In this study, people who ate fish at least once a week were 40 percent less likely to develop early ARM than their peers who ate fish less than once per month. People who ate fish three times per week had a substantially lower risk of advanced macular degeneration.
As for other types of fat, there was some evidence that older adults with low intakes of monounsaturated fat -- the type found in olive oil -- had an elevated risk of ARM. And fat sources that should generally be limited, such as butter, showed no relationship to ARM risk.
The stark difference between these findings and those of some earlier studies cannot be readily explained, according to the researchers. But the notion that healthy fats would raise ARM risk is counterintuitive and lacks biological plausibility, study co-author Dr. Jie Jin Wang of the
According to Wang and co-author Dr. Paul Mitchell, there's no reason for people to veer from what's considered a "heart-healthy" diet -- one emphasizing fruits, vegetables, whole grains and unsaturated fats from fish and plant sources.
A diet rich in omega-3 fats, the researchers noted, may also help lower the risks of high blood pressure, diabetes and obesity.
There are no definitive guidelines on dietary fat for people with early ARM, they said, but it would be "reasonable" for them to eat more fish and other sources of omega-3s.