Benefits
Supports macular pigment density
In a 1-year placebo-controlled trial, 2 mg zeaxanthin with 10 mg lutein raised macular pigment across the central retina. In older adults, mostly men, 8 mg zeaxanthin alone raised it about as much as lutein. A 6-month trial in adults with a family history of macular degeneration found no change, so results are mixed and mostly reflect the pair.
Visual recovery from bright light and color contrast
In 115 healthy young adults, a year of 10 mg lutein plus 2 mg zeaxanthin shortened recovery time after a bright flash and improved contrast for a target on a blue background versus placebo. Glare disability did not improve significantly. The two carotenoids were given together, so the share due to zeaxanthin is unknown.
Replaces beta-carotene in the AREDS2 eye vitamin formula
In a 5-year trial of 4,203 adults aged 50 to 85, adding lutein and zeaxanthin to the AREDS formula did not significantly reduce progression to advanced macular degeneration in the main analysis. Beta-carotene was linked to more lung cancers, mostly in former smokers, so the authors suggested the pair as a substitute.
Mechanism of action
Part of the macular pigment
Zeaxanthin joins lutein and meso-zeaxanthin in the macular pigment at the center of the retina. Supplements raise its blood level, and in trials macular pigment density rose over months of daily use, including at the fovea in older adults taking zeaxanthin alone.
Filtering short-wavelength light
Macular pigment absorbs blue light before it reaches the light-sensing cells. In a 1-year trial, raising it improved contrast for a target seen against a 460 nm blue background and sped recovery after a bright flash, which fits this filtering role.
Clinical trials
Multicenter, randomized, double-masked, placebo-controlled phase 3 trial with a 2 x 2 factorial design testing 10 mg lutein + 2 mg zeaxanthin, omega-3 fats, both, or placebo on top of the AREDS formula, NCT00345176 (AREDS2 Research Group 2013, JAMA).
4,203 adults aged 50 to 85 at risk of advanced age-related macular degeneration, with large drusen in both eyes or large drusen in one eye and advanced disease in the other.
After a median of 5 years, progression to advanced disease was 29% with lutein and zeaxanthin versus 31% with placebo, a difference that was not statistically significant (hazard ratio 0.90, P=.12). Removing beta-carotene did not change progression, and the beta-carotene group had more lung cancers (2.0% versus 0.9%), mostly in former smokers.
Randomized, double-blind, placebo-controlled 1-year trial of 10 mg lutein + 2 mg zeaxanthin daily, NCT00909090 (Hammond et al. 2014, Invest Ophthalmol Vis Sci).
115 healthy young adults: 57 on lutein and zeaxanthin, 58 on placebo.
Macular pigment rose versus placebo at every retinal location measured, and blood lutein and zeaxanthin rose by the first follow-up. Photostress recovery time and chromatic contrast improved versus placebo. Glare disability tracked macular pigment but did not improve significantly in the treated group.
Randomized, 1-year trial comparing 8 mg zeaxanthin, 8 mg zeaxanthin + 9 mg lutein, or 9 mg lutein as an active control, with no true placebo (Richer et al. 2011, Optometry).
60 older adults (57 men), mean age 74.9, with mild to moderate atrophic age-related macular degeneration.
Macular pigment rose in all three groups from 0.33 to 0.51 density units, with no difference between groups. The zeaxanthin group gained 1.5 lines of high-contrast acuity and showed trends in shape discrimination; the lutein group did better on low-contrast acuity, contrast sensitivity and glare recovery. The combined group raised macular pigment least. No adverse effects were reported.
Randomized, placebo-controlled 6-month trial of a lutein, zeaxanthin, omega-3 and vitamin supplement with 6 months of follow-up, NCT01269697 (Korobelnik et al. 2017, JAMA Ophthalmol).
120 adults with healthy retinas, mean age 56.7, whose parents had neovascular age-related macular degeneration.
Blood lutein and zeaxanthin rose versus placebo at 3 and 6 months, but macular pigment optical density, the primary outcome, did not change compared with placebo (P=.33).