The small, randomised trial carried out at the University of California, Davis, assessed the impact of Zeaxanthin (Z) -rich goji berry intake on macular pigment optical density (MPOD) and skin carotenoids on a healthy population.
While uncorrected refractive errors and cataracts are the top two leading causes of blindness worldwide, AMD follows in third place. MPOD is a non-invasive way of evaluating risk and is a biomarker for AMD.
A randomised trial
The macula xanthophyll pigments lutein (L) and zeaxanthin (Z) protect against blue light and offer oxidant defence, which can be measured by MPOD.
The research initially involved 88 volunteers between the ages of 45 and 65 in greater Sacremento, California, who were found via a website and through advertising in the area.
However, following a screening process and a review of inclusion criteria, a randomised trial was carried out among a total of 27 people.
They either ate 28 grams (g) of goji berries or took a supplement of six milligrams (mg) L and four mg Z (LZ), five times a week for a 90-day period.
At the end of the trial period, MPOD had significantly risen at 0.25 and 1.75 retinal eccentricities among the goji berry group while there were no changes in the LZ group.
Additionally, skin carotenoids were noted to have greatly increased among the goji berry group on the 45th and 90th days, but they had not in the LZ group.
The findings suggest that even among healthy people who do not show signs of early AMD, consumption of goji berries can benefit their eye health.
Other bioactive compounds found in goji berries, in addition to L and Z, may also contribute to the rise in MPOD.
The results further highlighted that a higher intake of Z relative to L could reduce the risk of AMD, which is consistent with findings from A Double-Blind, Placebo-Controlled study on the Effects of Lutein and Zeaxanthin on Neural Processing Speed and Efficiency, which showed greater MPOD levels after four months of taking supplements containing 20mg Z or 26mg Z with eight mg L, in addition to 190mg of mixed Omega-3 fatty acids by young healthy adults.
Goji berries were also discovered to be a credible dietary supplement for maintaining eye health is a study carried out in Singapore last year, particularly in preventing or delaying common retinal diseases among the ageing population.
Published online: doi.org/10.3390/nu13124409
‘Goji Berry Intake Increases Macular Pigment Optical Density in Healthy Adults: A Randomized Pilot Trial’
Authors: Xiang Li et al.