The health benefits of oily fish have been widely reported including reduced risk for heart disease, depression and certain kinds of cancers. Eating fish rich in omega-3 fatty acids has also long been thought to be good for maintaining eye health.
Now new research from Johns Hopkins University backs up previous studies showing that fatty fish-eaters tend to have lower rates of advanced age-related macular degeneration (AMD) -- a condition where vision becomes increasingly blurry and distorted due to damage to part of retina. This can impair basic daily activities such as reading, driving or even recognizing faces.
While there is no cure for AMD, there are some treatments and lifestyle changes that can help to prevent serious vision loss.
The study, published in the journal Ophthalmology, indicates that omega-3 fatty acids -- found in oily fish such as salmon, albacore tuna and mackerel -- may affect the development or progression of AMD.
Researchers looked at data from 2,520 adults aged 65 to 84 who underwent eye exams and completed detailed dietary questionnaires. And while they found no clear relationship between participants' reported fish intake and the risk of AMD, there was a link between higher intake of omega-3-rich fish and the odds of having advanced AMD, the most serious stage of the condition.
In fact, participants who ate one or more servings of such fish on a weekly basis were 60 per cent less likely to have advanced AMD than those who averaged less than a serving per week. However, the relationship between participant's fish intake and the risk of AMD -- as opposed to advanced AMD -- was less clear.
The study took into account known risk factors such as gender, race and smoking habits, which have been previously connected with AMD. (Women face a greater risk of AMD than men, whites are at greater risk than African Americans and smokers face a higher risk than non-smokers.)
"While the current research indicates that a diet rich in omega-3 fatty acids can reduce the risk of late AMD in some patients, more research is still necessary," study leader Bonnielin K. Swenor from Johns Hopkins University told Reuters.
The fact that the study was "cross-sectional" -- meaning it analyzed participants at one point in time rather than following them over time – means that its difficult to know for sure if the participants' reported diet habits preceded the development of the eye disease.
Foods For Healthy Eyes
In addition to fatty fish, there is growing evidence that fresh fruits and dark green, leafy vegetables -- foods rich in vitamins C and E, selenium, and carotenoids (including beta-carotene, lutein and zeaxanthin) -- may delay or reduce the severity of AMD.
To reap the most health benefits, select the freshest, most colourful veggies and fruits you can find -- think red, dark green, orange or yellow. Some top foods for your peepers include carrots, corn, kiwi, pumpkin, yellow squash, red grapes, tomatoes, spinach, kale, collard greens and green peas.
Nuts are another source of omega-3 fatty acids -- and they also contain copper, which it thought to play a role in preventing age-related eye diseases.
Foods to Avoid
A high-fat, high-cholesterol diet is not only bad for your heart, but it can lead to fatty plaque deposits in the macular vessels -- which can hamper blood flow and increase the risk of AMD.
Similar to guidelines for cardiovascular health, experts recommend maintaining a diet low in fat to keep your eyes healthy. Research has also shown that consuming red meat 10 times a week or more puts you at a 47 per cent higher risk for macular degeneration.
Vitamins and Supplements
A high-dose formulation of antioxidants and zinc can significantly reduce the risk of advanced AMD and its associated vision loss, according to The National Eye Institute's Age-Related Eye Disease Study (AREDS). This is often recommended for people with intermediate AMD in one or both eyes.
Because there can be harmful side effects, including urinary tract problems, to high-dose supplements, be sure to consult with your doctor before taking supplements in high doses.
Other Preventative Measures
Experts also recommend making other healthy lifestyle choices to help prevent AMD:
- Smoking. If you smoke, quit. Studies have shown that people who smoke may be 3-4 times more likely to have AMD.
- Exercise. Not only can physical activity reduce risk for AMD, but it may also slow progression of the disease.
- Watch your numbers. This includes controlling your weight, blood pressure and cholesterol levels.
- Adequate protection. Protect your eyes and be sure to wear sunglasses, especially in strong sunlight.