The goal of this project is to conduct a clinical trial in 60 participants ranging from age 65-95 who are at risk for age-related macular degeneration (AMD). The study will evaluate the effects of 14g of goji berry intake or an equivalent amount and type of fiber, five days a week for six months, on visual health, gut microbiome profiles, skin carotenoid measures, and lipoprotein profiles.
Age-related macular degeneration (AMD) is the third leading cause of blindness worldwide. The disease occurs when the macula in the central retina develops lesions due, in part, to the loss of the protection of macular pigments zeaxanthin, lutein, and meso-zeaxanthin, which are responsible for light filtering and oxidative defense. The major risk factor for AMD is aging, and currently, no definitive prevention for AMD exists. Goji berry (Lycium Barbarum) is a fruit that has been used as traditional medicine in Asian countries for more than 2,000 years. Modern science has identified potential benefits of the berry in oxidant defense, immune regulation, diabetes, and vision in animal and cell models. Nonetheless, evidence regarding the effects of goji berries on human health is scarce. The bioactive components of goji berries include zeaxanthin, lutein, Lycium Barbarum polysaccharides-protein complex, betaine, cerebroside, minerals, and vitamins. Importantly, goji berries contain the highest concentration of zeaxanthin among all commonly consumed foods. Previous clinical studies have shown that goji berries have a high bioavailability of zeaxanthin, and that macular pigment optical density (MPOD) was increased after supplementation. This study uses macular pigment optical volume (MPOV; a measure that integrates MPOD across multiple macular eccentricities) as the primary outcome measure. It is unknown if the changes in MPOV will be associated with other functional changes or anatomic conditions in the eye among a population with small drusen, a risk factor for AMD. In addition, the impact of goji berry intake on the gut microbiome profile and associated metabolites is unknown, and potentially important in understanding the mechanism(s) of action. Participants who meet the eligibility criteria will be enrolled and will be randomized 1:1 to the goji berry arm or fiber arm of the study. Over the course of approximately 180 days, participants will consume the assigned food item five days per week and attend three study visits. Study visits will include ophthalmic imaging and testing, skin carotenoid measurements, completion of a food record, height, weight, handgrip strength, blood pressure measurement, and fasting blood collection. At 2 timepoints participants will be asked to provide a stool sample (collected within 24 hours of visit).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
NONE
Enrollment
60
Participants will be instructed to consume 14 grams of goji berries 5 days a week for 6 months
Participants will be instructed to consume the fiber supplements 5 days a week for 6 months
UC Davis Eye Center, Tschannen Eye Institute
Sacramento, California, United States
RECRUITINGMacular pigment optical volume (MPOV)
MPOV provides an objective measure of macular pigments by using dual wavelength autofluorescence using the Heidelberg Spectralis to obtain HRA + OCT measures
Time frame: Day 0 and Day 180
Stool microbiome
Metagenomic sequencing
Time frame: Day 0 and Day 180
Spectral Domain-Ocular Coherence Tomography (SD-OCT)
Central subfield thickness will be measured using the OCT instrument's algorithm
Time frame: Day 0 and Day 180
Fundus autofluorescence (FAF)
Blue FAF imaging will be performed to assess variations in lipofuscin autofluorescence
Time frame: Day 0 and Day 180
Color Fundus Photography (CFP)
CFP imaging uses a standard retinal camera.
Time frame: Day 0 and Day 180
Microperimetry testing
Microperimetry will be tested according to a standard protocol using a Nidek MP-1 instrument
Time frame: Day 0 and Day 180
Dark adaptometry
Dark adaptometry will be assessed using a standard protocol.
Time frame: Day 0 and Day 180
Plasma microbial metabolites
Biogenic amines will be measures by LC-MS
Time frame: Day 0 and Day 180
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Plasma lutein and zeaxanthin
Plasma concentrations of lutein and zeaxanthin will be measured by LC-MS
Time frame: Day 0 and Day 180
Lipoprotein profile
Lipoprotein profiles will be measured according to standard protocols
Time frame: Day 0 and Day 180
HDL particle characteristics
Plasma will also be used to isolate and characterize HDL particles.
Time frame: Day 0 and Day 180
Peripheral blood mononuclear cells (PBMC) gene expression changes
PBMCs will be collected to monitor gene expression changes.
Time frame: Day 0 and Day 180
Cognitive function
Cognitive function will be assessed using web-based CANTAB tests
Time frame: Day 0 and Day 180
Handgrip strength
Handgrip strength will be measured using a Jamar hand dynamometer
Time frame: Day 0 and Day 180