🧬 Overview of Inherited Retinal Diseases (IRDs)
- IRDs involve progressive degeneration of photoreceptors, leading to irreversible vision loss.
- Nutritional supplementation is being explored as a potential adjunctive therapy to slow disease progression.
🥕 Vitamin A in Retinitis Pigmentosa (RP)
- Essential for the visual cycle and photoreceptor integrity.
- A landmark trial showed 15,000 IU/day vitamin A slowed ERG amplitude decline in RP patients.
- Later analyses questioned its overall efficacy, with possible benefits only in RHO-related RP.
- Risks include hepatotoxicity and teratogenicity—especially concerning for women of childbearing age.
🐟 Omega-3 Fatty Acids (DHA)
- DHA supports photoreceptor membrane structure.
- Mixed results in trials: some trends toward delayed progression in X-linked RP, but no significant ERG improvements.
- May help with visual field sensitivity and dark-adapted thresholds.
🛡️ Antioxidants and Oxidative Stress
Oxidative stress contributes to retinal degeneration. Several compounds have been studied:
🌿 Carotenoids (Lutein & Zeaxanthin)
- Act as natural blue light filters and antioxidants.
- Mixed trial results: some improvements in visual field decline, especially with higher serum lutein levels.
💊 N-Acetylcysteine (NAC)
- Precursor to glutathione, a key antioxidant.
- FIGHT-RP1 trial showed improvements in visual acuity and macular sensitivity.
- No structural preservation observed; Phase 3 trial underway.
🧪 Tauroursodeoxycholic Acid (TUDCA)
- Shows neuroprotective effects in animal models (anti-apoptotic, anti-inflammatory).
- No clinical trials yet to validate efficacy in humans.
🌱 Curcumin
- Anti-inflammatory and antioxidant properties.
- Limited by poor bioavailability despite promising preclinical results.
🌼 Saffron
- Contains safranal and crocetin, which may slow photoreceptor degeneration.
- Combined with photobiomodulation, initial synergy was suggested but later studies showed limited or antagonistic effects.
🧠 Precision Medicine Potential
- Genetic profiling may help identify which patients benefit most from specific supplements.
⚠️ Clinical Takeaways
- Nutritional supplementation offers promise but faces challenges:
- Limited bioavailability
- Inconsistent study designs
- Lack of long-term clinical validation
- Until stronger evidence emerges, supplements remain more of a hopeful adjunct than a proven therapy.
Morales, P. C., Estrada-Puente, C., & Maldonado, R. (2025). Nutritional Supplementation for IRDs: Preservation or Placebo? Retina Today, July/August 2025, pp. 44–46.
