Macular Pigment Optical Density Clinical Trial
Official title:
The Effect of Gojiberry Intake (Lycium Barbarium) on Macular Function
Objective: To evaluate the effects of goji berry intake for three months on macular pigment
ocular density (MPOD) between 45 and 65 years old.
Specific Aims:
Determine if goji berry intake for 90 days, 5 times per week, will:
- result in favorable changes in macular pigment optical density (MPOD), as measured using
heterochromatic flicker photometry (HFP), in adults aged from 45 to 65 years old.
- impact the carotenoid distribution in the skin.
- will change the fermentation capacity of the gut microbiota.
The investigators hypothesize that the intake of 28 grams of goji berry for 90 days, 5 days
per week will significantly increase MPOD after three months, compared to baseline values. In
contrast, the investigators hypothesize that a dietary supplement of lutein and zeaxanthin
will not alter MPOD.
Prior to enrollment, all volunteers that meet the initial inclusion and exclusion based on a
telephone interview will be asked to participate in a clinical screening visit, which will
assess the subject's overall health, and whether the individual meets the inclusion and
exclusion criteria. To determine normal eye health, subjects will provide a statement from
their optometrist verifying normal functioning. The study will be conducted in the Ragle
Human Nutrition Research Center on the UC Davis campus. The participants will be consented
into the study. For those who are not familiar with goji berry, a sample tasting will be
provided. In addition, each volunteer will be asked to complete a diet and health habits
questionnaire. The first study visit will begin on the same day after the screening visit is
done.
The study will be a randomized, controlled, parallel arm design with two groups: goji berry
or lutein/zeaxanthin (L/Z) supplement. Participants will be randomly assigned to one of the
two groups using a block design that will place an approximately similar number of males and
females in each group. The randomization will be conducted by an online tool called Research
Randomizer.
The study will include three study visits over a 90 days period, with study visit one (SV1)
occurring at day 0, SV2 conducted at day 45, and SV3 conducted at day 90. The first study
visit will occur immediately after consent is completed.
Depending on group assignment, the participant will be provided with either a 45-day supply
of goji berries or L/Z supplements which contains 6 mg of lutein and 4 mg of zeaxanthin and
will be asked to consume the given items five days per week. After the 45-day intake period,
the participants will return to the lab for SV2 and then be given a new 45-day supply of
items to consume until the end of the 90 day test period (SV3). Participants will complete a
log in order to verify compliance. Dietary recall will be collected by using the Automated
Self-Administered 24-hour dietary assessment (ASA24) web-based tool between each SV.
MPOD measurement - MPOD will be assessed by the psychophysical method of HFP technology
(Macular Metrics, Providence, RI). Participants will watch a 20 minutes long video of a
description of HFP. After adapting to the dark for seven minutes, participants will be asked
to rest their head on a chin rest and look at a blue background field for three minutes.
Prior to each test, the light intensity from each wavelength will be calibrated with a
photodiode. The flicker frequency is selected for each subject based on preliminary tests of
flicker sensitivity. The observer's task is to eliminate or minimize the flicker by turning a
dial that changes the intensity of the 460-nm light. They will be asked to do this when
looking directly at the flickering light and also when looking at a fixation point so that
the stimulus can be presented in the periphery.
Skin carotenoid measurement - the carotenoid content in the skin will be measured through a
finger-scanning device using reflection spectroscopy (this process does not capture
fingerprints) called the Veggie Meter (VM). This noninvasive method of measuring skin
carotenoid levels has been validated to reflect plasma carotenoid concentrations.
Breath Hydrogen measurement - the participant will be asked to do one short exhalation (about
2-3 seconds) into a collection tube. Their breath sample will be analyzed for hydrogen and
methane that are produced by fermentation of carbohydrates (including fiber) in the digestive
tract.
Compliance will be assessed verbally and through self-reported logs indicating consumption of
the product. Dietary recall will be collected by using the Automated Self-Administered
24-hour dietary assessment (ASA24) web-based tool during each study arm, and a weekly log
book of digestive tract symptoms, which will record a typical symptom such as bloating, gas,
intestinal cramps, and loose stools.
;
| Status | Clinical Trial | Phase | |
|---|---|---|---|
| Completed |
NCT00449917 -
"Visiobiane Anti-age" Effects on Vision Parameters
|
Phase 4 | |
| Recruiting |
NCT05251792 -
Macular Pigment Optical Density in Primary Angle-closure Disease
|
||
| Recruiting |
NCT03433885 -
Wenzhou Dry Age-related Macular Degeneration (AMD) Progression Study
|