* "Dietary intake of DHA (omega 3 fatty acid) is associated with several health benefits, including normal brain and eye function2. .. <i>mice that lack the protein Mfsd2a</i>, which transports DHA across the blood–brain barrier into the brain, develop severe retinal and brain dysfunction3"<p>* A quick search shows that a) DHAs are vital for brain function and b) the role of Mfsd2a is known: "Mfsd2a-deficient (Mfsd2a-knockout) mice show markedly reduced levels of DHA in brain accompanied by neuronal cell loss in hippocampus and cerebellum, as well as cognitive deficits and severe anxiety, and microcephaly. " <a href="https://www.nature.com/articles/nature13241?WT.feed_name=subjects_phospholipids" rel="nofollow">https://www.nature.com/articles/nature13241?WT.feed_name=sub...</a><p>* OP paper says: DHA and DHA oxidation produced epoxide metabolites "are associated with beneficial retinal effects" and an enzyme called sEH degrade them to form 19,20-DHDP, "suggesting that sEH has a causal role in diabetic retinopathy." (which is "a major cause of blindness in middle age").<p>* Then .. plot twist: And then "Hu and colleagues showed that it is the production of 19,20-DHDP, rather than the reduction in DHA or epoxide molecules, that is the key trigger of vascular degeneration.<p>* "19,20-DHDP acts through a different mechanism from that of another player in retinopathy — vascular endothelial growth factor (VEGF). This protein is induced under low-oxygen conditions.."<p>* So the real villain here is increased sEH and the question for future research is "what triggers increases in sEH production in diabetic retinopathy"
I've had type 1 diabetes for 12 years, in the recent couple of years I occasionally take Omega3 and DHA supplements every day. My daily intake is 300 mg of Omega 3, 180 mg of EPA, 120 mg of DHA.<p>I couldn't really understand the full article. Does this mean I should switch to pure Vitamin D supplements instead of DHA?<p>As far as I could find, current understanding is that Omega3 (EPA and DHA) help prevent vascular damage and retinopathy.<p>"Mice receiving the omega-3 rich diet were observed to have 40-50% less initial retinal vessel loss compared to omega-6 fed mice.
As a result, the omega-3 group had a similar 40-50% reduction in pathological vessel growth.
The results were virtually identical in the Fat-1 mice, confirming that increased retinal omega-3 levels inhibited neo-vascularization." (Source: <a href="http://www.sciencebasedhealth.com/-DHA-and-EPA-May-Protect-Against-Retinopathy-W71.aspx" rel="nofollow">http://www.sciencebasedhealth.com/-DHA-and-EPA-May-Protect-A...</a>)
"The molecule 19,20-dihydroxydocosapentaenoic acid, formed by the metabolism of a fatty acid involved in normal brain function, promotes the development of a diabetes-associated form of blindness in a mouse model."<p>tl;dr Mice should be really careful when consuming too much omega-3 fatty acids.