Observational studies have suggested that higher intake or blood levels of vitamin D and marine omega-3 fatty acids may be associated with lower risks of age-related macular degeneration (AMD). A recent large randomized trial (VITAL), however, has concluded that supplementation with vitamin D3 and marine omega-3 fatty acids actually had no significant overall effect on AMD incidence or progression.
25,871 adult US men and women, mean age 67.1, consumed daily supplementation with vitamin D3(2000 IU) and marine omega-3 fatty acids (1 g) for a median of 5.3 years. Randomization was from November 2011 to March 2014, and study pill-taking ended as planned on December 31, 2017. This the first randomized trial to examine vitamin D in AMD prevention. On the other hand, omega-3 has been studied in two past trials, most notably the AREDS2, but results have been uncertain.
In view of several minor limitations, the VITAL study has offered the most solid evidence to date that neither vitamin D3 nor omega-3 supplementation, while beneficial for other conditions, offer no specific prevention against AMD.
Effect of Vitamin D and ω-3 Fatty Acid Supplementation on Risk of Age-Related Macular Degeneration: An Ancillary Study of the VITAL Randomized Clinical Trial. William G. Christen, ScD1 (JAMA Ophthalmol. Published online October 29, 2020. doi:10.1001/jamaophthalmol.2020.4409)