Consumption of fatty acids found in fish helps in preventing age-related maculopathy, a deterioration of the retina that leads to blindness. Previous studies 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, Forbes reported.
But the findings are puzzling because unsaturated fats from fish and plant sources like olive oil are widely recognised as healthy fats that may protect against heart disease and other ills.
Researchers from Sydney followed more than 3,600 older adults for five years and found no evidence that dietary fat, of any kind, increased the risk of ARM.
It was also found that men and women who ate the most omega-3 fatty acids had a lower risk of ARM than those who ate less. Omega-3 polyunsaturated fats are found largely in oily fish, and to a lesser extent in flaxseed, walnuts and soybeans.
People who ate fish at least once a week were 40 percent less likely to develop early ARM than those who ate fish less than once per month. People who ate fish thrice a week had a substantially lower risk of advanced macular degeneration.
For other types of fat, there was some evidence that older adults with low intakes of monounsaturated fat (found in olive oil) had an elevated risk of ARM. Fat sources that should generally be limited, such as butter, showed no relationship to ARM risk.
The stark difference between the current and previous findings cannot be readily explained. But the notion that healthy fats would raise ARM risk is counterintuitive and lacks biological plausibility.
There's no reason for people to turn away from a heart-healthy diet, which emphasises fruits, vegetables, whole grains and unsaturated fats from fish and plant sources. A diet rich in omega-3 fats, 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, but it would be reasonable for them to eat more fish and other sources of omega-3 fatty acids.