There may be another good reason to eat fish, a food containing a fatty acid called omega-3. Researchers have found that a diet enriched with omega-3 helps repair and prevent retinal damage in mice, a discovery with potential for preventing blindness in premature infants and adults suffering from age-related macular degeneration.
Nature Medicine published the omega-3 study, written by a team that included Harvard University ophthalmology researcher Kip Connor, in June. “With just a 2 percent change in dietary omega-3, there was a 40 to 50 percent decrease in the disease pathology,” Connor says.
The researchers fed almost identical diets to two groups of female mice nursing litters. One diet was enriched with 2 percent omega-3 fatty acid, mirroring a Japanese diet, the other with 2 percent omega-6 fatty acid, similar to a typical American diet.
The litters were also exposed to high levels of oxygen, which causes a loss of blood vessels in retinal tissue. When oxygen levels are restored to normal, the eye senses it as a lack of oxygen and responds by growing new blood vessels, which often leads to excessive growth and damage to vision. This happened to the offspring of the mothers receiving omega-6, but the pups receiving omega-3 through their mothers’ milk grew new vessels at a healthy rate.
In humans, abnormal and excessive blood vessel growth related to decreased oxygen supply is the most common cause of blindness in premature babies, diabetics, and the elderly. It affects some 4 million people in the United States alone. Connor and other researchers are studying the impact of omega-3 and -6 on human eyesight and will release the results later in 2008.
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