Some observational studies suggest that vitamin D and marine omega-3 fatty acids may be associated with a lower risk of developing AMD; however, there’s limited evidence from randomized trials. A recent, large-scale randomized trial took on this gap in the literature and found the supplements had no significant effect on AMD incidence or progression.

The randomized, placebo-controlled clinical trial was an ancillary study of the Vitamin D and Omega-3 Trial (VITAL), a nationwide study on the potential effects of these supplements in preventing cancer and cardiovascular disease. For AMD study purposes, the researchers included 25,871 adults taking vitamin D₃ (2,000IU) and omega-3 fatty acids (1g) daily for a median of 5.3 years.

The participants were around 67 years of age (50.6% female, 71.3% white and 20.2% Black). Over the course of the study follow-up period, 324 participants experienced an AMD event (285 incident AMD and 39 progression to advanced AMD). Those taking vitamin D₃ experienced 163 AMD events, while the placebo group experienced 161. In the omega-3 group, 157 AMD events occurred compared with 167 in the placebo group.

The researchers reported hazard ratios in the vitamin D₃ group of 1.09 for incident AMD and 0.63 for AMD progression. In the omega-3 group, they reported 0.93 for incident AMD and 1.05 for AMD progression. They concluded that neither supplement had a significant effect on AMD.