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Fish-rich diet linked to lower risk of macular degeneration
BMJ Group News
Women who consume high amounts of omega-3 fatty acids from fish have a lower risk of macular degeneration, a leading cause of blindness in older people, reports a new study. However, it's too soon to say whether these fats can actually help prevent this eye disease.
What do we know already?
Macular degeneration damages the middle of your vision, making it hard to see things that are straight in front of you. There's no cure for macular degeneration, but treatments can help to slow vision loss, and may give some improvement to sight.
Research suggests that a diet high in omega-3 fatty acids might also help. These fats, which are plentiful in salmon and other oily fish, may help to reduce inflammation and prevent cell damage in macular degeneration. Supporting this theory are several studies showing that people with macular degeneration who consume high levels of omega-3 fatty acids are less likely to develop an advanced form of the disease.
However, less research has looked at whether omega-3 fatty acids might stop macular degeneration from developing in the first place. There are currently no known ways to prevent the disease.
To learn more, researchers looked at a group of 38,022 middle-aged women who took part in a study that assessed their diets and then tracked their health, including whether they got macular degeneration.
What does the new study say?
Over 10 years, 235 women were diagnosed with macular degeneration. Those who ate fish one or more times a week were 42 percent less likely to develop the disease than those who ate fish less than once a month. Canned tuna and dark-meat fish were most closely linked to a reduction in risk.
The researchers also found a lower risk with two types of omega-3 fatty acids found in the women's diets: DHA (docosanexaenoic acid) and EPA (eicosapentaenoic acid). Women who had the highest intake of DHA had a 38 percent lower risk than those who had the lowest intake, and high levels of EPA were linked to a 36 percent drop in risk.
These findings remained steady when researchers took into account other factors that might have affected women's risk of macular degeneration, including what other fats they ate, and whether they smoked, were overweight, took multivitamins, or had high blood pressure, high cholesterol, or diabetes.
How reliable are the findings?
This study provides fairly strong support for the theory that omega-3 fatty acids can help prevent macular degeneration. However, this is still just a theory. This type of study can't show cause and effect, so it can't prove that consuming high amounts of omega-3 fatty acids was what lowered women's risk. There could have been something else about their diet or lifestyle that made a difference.