Age-related macular degeneration (AMD)
affects 10 million Americans and is the leading cause of blindness in people age 65 and older. The macula, situated in the middle of the retina, is essential for the central vision used in reading, driving, and recognizing faces. With AMD, damage to the macula causes blurriness and a progressive loss of sight. Treatment can slow vision loss in some cases, but there is no cure for AMD. Much research is focused on prevention.
Researchers evaluated the effects of two lifestyle factors—smoking and eating fish—on the risk of AMD. Among the elderly men studied, current smokers had nearly twice the risk of AMD as nonsmokers, while risk was lower among those regularly consuming fish rich in omega-3 fatty acids. These findings are in the July 2006
Archives of Ophthalmology
About the Study
Researchers from the Massachusetts Eye and Ear Infirmary interviewed 681 elderly, male twins about their smoking habits and other health-related factors. The men also underwent a thorough eye exam and completed a food frequency questionnaire. Using this data, the researchers compared the eating and smoking habits of the 222 men with AMD and the 459 without it.
Current smokers had almost double the risk of AMD, while past smokers had a 1.7-fold greater risk than men who never smoked. Thirty-two percent of AMD cases in this cohort study were due to smoking.
On the bright side, men who ate two or more servings per week of fish rich in omega-3 fatty acids cut their AMD risk. Specifically, the men who ate the most omega-3 fatty acids enjoyed a protective effect from their fish consumption. AMD incidence in this group could be cut by 22% if all men consumed 0.35 grams of omega-3 fatty acids per day—about 2 servings (3-ounces each) of salmon per week.
Since this study was limited to men, it is unclear if the effects will be the same in women. However, another study in the same issue of the
Archives of Ophthalmology
found that a diet rich in omega-3 fatty acids protected against AMD in both men and women in Australia. In this cohort study, eating fish at least once per week reduced the risk of early AMD by 40%, while three or more servings per week lowered the risk for more advanced forms of the disease.
How Does This Affect You?
Should you add more fish to your diet? Absolutely. While the evidence to date is not conclusive, there is still enough to strongly suggest that a diet rich in omega-3 fatty acids from fish has significant health benefits. The American Heart Association already recommends two fish meals per week based on its heart benefits. And research has also connected a diet rich in fish fat with a lowered risk
. Now you can add AMD to the list!
Aim to eat fatty fish (3-5 ounces) 2-3 times per week. Ideally, fish should replace foods high in saturated fat, such as beef or fried chicken. Good sources of omega-3 fatty acids include the following:
A note of caution: some fish contain mercury, which is dangerous for children and women who are pregnant, breastfeeding, or may become pregnant. These women and children should avoid shark, swordfish, tilefish, and king mackerel; and limit consumption of tuna and red snapper.
To get the full benefit of omega-3 fatty acids, minimize intake of linoleic acid, which is an omega-6 fatty acid. Most linoleic acid in the American diet comes from processed foods made with vegetable oils, such as safflower, sunflower, corn, and soybean oils. Choose fresh fruits, vegetables, and meats whenever possible, and avoid snack foods and prepared meals. Use olive oil and canola oil when cooking.
Also, the findings on smoking should not be overlooked. AMD is just one of many serious and debilitating conditions that are linked to cigarette smoking. If you smoke, quit. Take advantage of available resources to help kick the habit, such as support groups and nicotine patches.
Chua B, Flood V, Rochtchina E, et al. Dietary fatty acids and the 5-year incidence of age-related maculopathy.
Parmet S. Age-related macular degeneration [patient page].
Seddon JM, George S, Rosner B. Cigarette smoking, fish consumption, omega-3 fatty acid intake, and associations with age-related macular degeneration. The US twin study of age-related macular degeneration.
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a