A study came out earlier this year (thanks, Tom!) shedding some light on the issue of the short-chain omega-3 fatty acid, alpha-linolenic acid (ALA), and eye damage. Previous research from the Nurse’s Health Study had linked ALA intake to age-related macular degeneration (AMD) and cataracts. My suspicion is that this was due to confounding, but until more is known, I have been discouraging vegans from taking large amounts of ALA.
This new study from France (1) measured ALA levels in the blood, rather than from the diet, and found that higher blood levels of ALA were associated with a reduced risk of late-AMD.
This gives me quite a bit of confidence that the association of ALA with AMD in the Nurse’s Health Study was probably due to confounding. However, we are not out of the woods on yet on AMD and definitely not on cataracts. I hope we know more soon.
You can read more details in the section Eyesight of the VeganHealth.org article, Omega-3 Fatty Acid Recommendations for Vegetarians.
1. Merle BM, Delyfer MN, Korobelnik JF, Rougier MB, Malet F, Féart C, Le Goff M, Peuchant E, Letenneur L, Dartigues JF, Colin J, Barberger-Gateau P, Delcourt C. High concentrations of plasma n3 fatty acids are associated with decreased risk for late age-related macular degeneration. J Nutr. 2013 Apr;143(4):505-11. | link