Standardised Tagetes Erecta Lutein and Zeaxanthin for Macular Health and Visual Performance: A Narrative Review

Abstract

Lutein and zeaxanthin are the xanthophyll carotenoids of the human macular pigment; because neither is synthesised in the body, the retina depends on dietary and supplemental intake. Marigold (Tagetes erecta) flowers are the principal natural feedstock for commercial lutein and its fatty-acid esters, placing this plant at the centre of nutritional eye care. This review assesses the clinical literature on T. erecta-derived lutein and zeaxanthin and the potential for standardising their use in vision supplements. In cellular and animal models, the mechanism of action is consistent with ocular protection through blue-light screening and antioxidant activity: lutein and zeaxanthin counter oxidative stress and damage to retinal pigment epithelium cells and photoreceptors, reduce inflammation, and support mitochondrial function via Nrf2/HO-1 pathways. In human randomised controlled trials, increased macular pigment optical density (MPOD) is linked to improved contrast sensitivity and visual performance under glare or photostress. Two independent meta-analyses found that dietary supplementation raised MPOD more in patients with age-related macular degeneration (AMD) and improved visual function, with a possible reduction in progression risk. Recent interventional studies in computer users report mostly positive effects on visual comfort and eye dryness, though largely from self-reported data and considered preliminary. AREDS2 established lutein/zeaxanthin as a lower-risk alternative to beta-carotene that may slow progression in certain AMD patients but does not prevent eye disease generally. Further research is needed to define clinically relevant doses, and few studies have examined finished T. erecta products rather than isolated extract components.