Study: Eating Fish Protects Against Diabetic Retinopathy in Asians

Eating more fish has been shown to decrease the severity and frequency of diabetic retinopathy in patients in Spain and Australia, but what about the rest of the world?

New evidence suggests that the same could be said for Asian populations, according to Jaqueline Chua, PhD, B. Optom, FAAO, of the Singapore Eye Research Institute.

“It’s unclear if the findings from Australia and Spain can be found in Asians,” she said. “Although Asians are starting to adopt western dietary habits, there are still fundamental differences in dietary patterns between these two populations. We wanted to find out if there was an association of dietary fish intake with the severity of diabetic retinopathy in Asians with type 2 diabetes.”

In a presentation at the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO) in Baltimore, Maryland, Chua said she became interested in the topic when she learned that Singapore has the second highest prevalence of diabetes, behind only the United States.

To start, Chua and her team began monitoring the dietary habits of 357 participants from Singapore. They were given food frequency questionnaires and underwent clinical exams, ocular exams, face to face interviews, and a medical history review. Non-fasting blood samples and retinal photographs were taken from each participant.

Participants were 57 years of age on average and predominantly of Chinese descent. Their mean fish consumption was 3.4 weekly servings, and the overall prevalence of diabetic retinopathy was 60%, with 40% made up of individuals with minimal to moderate diabetic retinopathy, and 20% of participants having severe diabetic retinopathy.

“When we adjusted for age, gender, race, lifestyle and clinical variables, we saw that there were 65% reduced odds of having diabetic retinopathy [in patients with higher fish intake], with every unit increase of fish intake resulting in a 10% reduction in diabetic retinopathy severity,” Chua said.

According to the researchers involved, this suggests that there is a biological association for fish intake and diabetic retinopathy risk that may be broadly consistent across ethnic boundaries.

“This may become one of the cornerstones of diabetes care, which can be potentially very useful in clinical and research settings,” Chua said.

Limitations of the study included the fact that while there is a strong correlation between dietary fish intake and reduction in the severity of diabetic retinopathy, there is not a causal relationship between the two.

“The potential benefits of fish intake on diabetic retinopathy can be attributed to omega 3 fatty acids, but the questionnaire we gave participants did not include [a question about] what type of fish participants were eating, so we did not know where the source of omega 3 fatty acid was coming from,” Chua said.