A long-term, large US study has found that vitamin D and omega-3 supplements have little effect on the development and progression of age-related macular degeneration (AMD).

The nationwide observational study, Ancillary study of the VITAL randomised clinical trial, included 25,871 participants (50.6% women; 71.3% non-Hispanic, white; and 20.2% black) with a mean age of 67.1 years. Participants received a randomised, daily supplementation of vitamin D3 (2000 IU), marine omega-3 (1g) or placebo.

After a median range of 5.3 years of treatment and follow-up, findings showed neither vitamin D nor omega-3 supplements had a significant overall effect on AMD incidence or progression. Overall, 324 participants experienced an AMD event (285 incident, 39 progression to advanced AMD). Looking at the groups separately, there were 163 events in the vitamin D3-treated group and 161 in the placebo group, while the omega-3 group experienced 157 events in the treated group and 167 in the placebo group.

Dr Robert Frank of the Kresge Eye Institute at Wayne State University School of Medicine in Detroit, writing in an invited commentary for Jama Ophthalmology, said the findings were “discouraging”.

“This is especially the case, because the prior successes of AREDS and AREDS2 have led to considerable optimism that at least one, and possibly other, common and highly disabling eye diseases can be substantially reduced in severity, or even prevented, by large but safe doses of commonly used and inexpensive vitamins and dietary supplements. That possibility has not been supported in the present instance.”