Dr. Grossman’s Blog

Researchers have released a new study showing that regular consumption of fish, omega-3 polyunsaturated fatty acids, and nuts helps protect against age-related macular degeneration (AMD).

The study, published in the Archives of Ophthalmology, assessed the relationship between dietary fatty acids and the 10-year incident of AMD.

Scientists examined 3654 elderly Australian participants at baseline and re-examined 2454 of these participants five and/or ten years later.  Participants completed a food frequency questionnaire.

The findings confirmed many previous studies on AMD.  After adjusting for age, sex, and smoking:

• one serving of fish per week was associated with reduced risk of early AMD primarily among participants with less than the median linoleic acid consumption
• findings were similar for consumption of long-chain omega-3 polyunsaturated fatty acids:  one to two servings of nuts per week was associated with reduced risk of early AMD 
• protective associations between nut consumption and reduced risk of pigmentary abnormalities were seen among nonsmokers, participants with less than the median ratio of serum total to high-density lipoprotein cholesterol, and those with beta carotene intake greater than the median level.

This study provides evidence of protection against early AMD through:

• regular consumption of fish and nuts
• greater consumption of omega-3 polyunsaturated fatty acids
• low intakes of foods rich in linoleic acid

Read more about AMD and natural eye care

Learn which foods to eat to help maintain good eye health

SOURCE:  Dietary Fatty Acids and the 10-Year Incidence of Age-Related Macular Degeneration, The Blue Mountains Eye Study, Tan, et al, Arch Ophthalmol. 2009;127(5):656-665.

A study published in the American Journal of Clinical Nutrition found that eating one portion of omega-3 fatty acid-rich fish per week may reduce the risk of age-related macular degeneration (AMD) by over 50 percent.

2,275 people over 65 years of age participated in the EUREYE Study. They were given eye exams and completed a food frequency questionnaire.

Researchers found that oily fish was consumed less than once per week by 64% of the study population, once per week by 25%, and twice per week or more by 12%.

Those eating oily fish at least once per week had a 50% reduced risk of a type of AMD called neovascular AMD (NV-AMD), while those eating oily fish at least twice per week had a 58% reduced risk.

Good choices for fish rich in omega-3 fatty acids are cold water oily fish such as salmon, herring, mackerel, anchovies and sardines.

Read other research showing the benefits of omega-3 fatty acids for healthy vision

Learn more about natural omega-3 vision supplements

SOURCE: Augood, et al; Oily fish consumption, dietary docosahexaenoic acid and eicosapentaenoic acid intakes, and associations with neovascular age-related macular degeneration; Am. J. Clinical Nutrition, Vol. 88, No. 2, 398-406, August 2008.

Data in US Twin Study also shows consumption of fish rich in omega-3 fatty acids helps fight AMD

In a study of male twins, research shows that those who smoke have an increased risk of developing age-related macular degeneration.  Men who ate more fish rich in omega-3 fatty acids had a lower risk of developing the disease.

Researchers collected data on 681 elderly male twins from the National Academy of Sciences National Research Council World War II Veteran Twin Registry.  The twins were given an eye exam and completed a food frequency and a risk-factor questionnaire.  222 of the twins had intermediate and late-stage age-related macular degeneration, while 459 of the twins had no signs of the disease.

The study showed that current smokers had a 1.9-fold increased risk of developing age-related macular degeneration, while past smokers had about a 1.7-fold increased risk.

Consumption of omega-3 fatty acids from fish reduced the risk of AMD, particularly if two or more servings of fish were consumed each week.

Although researchers noted that genetics are important in determining who will get AMD, lifestyle choices, such as smoking, play a role as well. 

What can you do to reduce your risk of AMD?  Eat a healthy diet, including omega-3 fatty acids from fish such as mackerel, lake trout, sardines, albacore tuna and salmon.  Experts also recommend exercising, refraining from smoking, and maintaining a normal healthy weight.

Learn more about Age-Related Macular Degeneration (AMD)

Read more studies about the benefits of omega-3 fatty acids for healthy vision

SOURCE:  Seddon, et al; Cigarette Smoking, Fish Consumption, Omega-3 Fatty Acid Intake, and Associations With Age-Related Macular Degeneration; Arch Ophthalmol. 2006;124:995-1001.

Researchers using data from the Third National Health and Nutrition Examination Survey (1988 through 1994) have found evidence that consuming vitamin D may help ward off age-related macular degeneration (AMD). 

In this study, 7752 individuals (including 11% with AMD) were given retinal photographs, dietary intake questionnaires, and blood tests to calculate blood vitamin D (25-hydroxyvitamin D) levels.  Based on these vitamin D blood levels, participants were divided into 5 groups.   Participants in the group with the highest vitamin D levels showed 40% lower risk of developing early AMD than those in the lowest group. 

Analysis was also conducted to evaluate associations with important food and supplemental sources of vitamin D. 

• People who drank milk daily decreased their risk of developing AMD, as did those who took supplemental vitamin D consistently but didn’t drink milk daily. 
• Fish consumption was also linked with a lower risk of advanced AMD.

What are good sources of vitamin D?  Consider fish — it’s naturally rich in vitamin D.  Milk and breakfast cereals are generally fortified with vitamin D as well. 

Read more about AMD

Learn tips for taking vitamins and maintaining good digestion

SOURCE:  “Association between vitamin D and age-related macular degeneration in the Third National Health and Nutrition Examination Survey”, Parekh N, et al. Arch of Ophthalmol 125:661-69, 2007.

Researchers with the Hordaland Health Study reviewed the relationship between consumption of different amounts of fish (and fish products) and cognitive performance.

In this study, 2031 subjects in Norway aged 70 to 74 underwent a battery of six cognitive tests and completed food-frequency questionnaires that identified both the quantity and the type of fish consumed in their diet. Researchers then studied the associations between cognitive performance and the main types of consumed seafood, i.e., fatty fish, lean fish, processed fish, fish sandwich, and fish or cod liver oil.

They found that fish eaters had significantly better results on all cognitive tests than did the non-consumers, even after adjustment for several non-nutritional factors with a proven association with cognition (e.g., education levels).

The protective effect of eating fish and fish products extended to almost all of the tested cognitive abilities. In addition, the associations between fish and fish product intake and cognition were dose-dependent: those who ate greater amounts of fish showed better test results.

The researchers also observed that the results depend on the type of fish consumed: the effect was more pronounced for non-processed lean fish and fatty fish.

Read other studies that link fish consumption to improved eye health

Learn more about natural fish oil products

SOURCE: “Cognitive performance among the elderly and dietary fish intake: the Hordaland Health Study”, Nurk, et. al., Am J Clin Nutr; 86:1470-1478 (November 2007).