Impact of Grape Powder Consumption on Eye Health and Glycemic Status in Singapore Older Adults

November 12, 2024 updated by: Jung Eun Kim, National University of Singapore

Impact of Regular Consumption of Grape on Eye Health and Regulation of Advanced Glycation End-products in Singapore Older Adults

The purpose of this study is to understand the impacts of regular consumption of freeze-dried table grape powder on eye health and regulation of advanced glycation end products in Singapore older adults. The investigators hypothesize that regular consumption of freeze-dried table grape powder will promote improvements in eye health and lower levels of advanced glycation end products when compared to the placebo group.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The study will be a 16-week, double-blind, randomized, placebo-controlled trial using a parallel study design. 46 adults (aged 60 - 85) will be recruited and randomly assigned to the intervention or placebo group to investigate whether regular consumption of freeze-dried table grape powder (46g/d) can improve eye health parameters, blood/skin AGE and glycemic status, and reduce inflammation and oxidative stress. This study will consist of 1 screening visit and 5 study visits with 4-week intervals.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
46

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Singapore
      • Singapore, Singapore, 117550
        • Recruiting
        • National University of Singapore, Faculty of Science, Department of Food Science and Technology
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Male and female participants, aged between 60 and 85 years old inclusive
  2. English-literate and able to give informed consent in English

Exclusion Criteria:

  1. Smokers
  2. Allergy to grapes or food dyes/additives, or had serious food allergies in the past
  3. Known eye diseases (macular degeneration, cataracts, retinopathy or glaucoma), blindness in at least one eye or have had eye surgery
  4. Unable to view bright lights or flashing lights
  5. Has Type 1 or 2 diabetes, uremia, cardiovascular disease, abnormal kidney and liver function
  6. Taking eye medication and/or dietary supplements for the eyes for the past 3 month
  7. Taking supplements containing carotenoids (e.g. Vitamin A, lutein, zeaxanthin) for past 3 months
  8. Currently on a specialised diet (e.g. vegetarian, vegan, weight loss diet, low fat diet
  9. Consumes more than 2 alcoholic drinks per day i.e. one drink is defined as either 150ml of wine,340ml of beer/cider or 45ml of distilled spirit
  10. Significant change in weight (≥ 3 kg body weight) in the past 3 months
  11. Significant exercise pattern over the past 3 months defined as high-intensity exercise of more than 3 hours per week
  12. Currently on anti-hypertensive, cholesterol-lowering or psychoactive drugs
  13. Scored ≤ 7 on the abbreviated mental test
  14. Poor peripheral venous access based on past experiences with blood draw
  15. Participating in another clinical study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Freeze-dried table grape powder
Subjects in this group will be given pouches, each containing 46 g of freeze-dried table grape powder, with an instruction sheet on how to prepare the powder into a drink for consumption.They will consume one pouch a day.
Dietary supplement: Freeze-dried table grape powder
Consumption of grape powder as part of daily diet
Placebo Comparator: Placebo table grape powder
Subjects in this group will be given pouches, each containing 46 g of placebo grape powder, with an instruction sheet on how to prepare the powder into a drink for consumption.They will consume one pouch a day.
Dietary supplement: Placebo grape powder
Consumption of placebo grape powder as part of daily diet

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Macular pigment optical density
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16
A measurement of macular pigment of the eye using a heterochromatic flicker photometry device. The measurements are in arbitrary units.
Week 0, Week 4, Week 8, Week 12, Week 16
Visual acuity
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16
Participants will read out letters on a ETDRS LogMAR chart at a fixed distance where letters becomes smaller as it goes down the chart. Tests results will be recorded in number of letters read, where the more letters the better the outcome.
Week 0, Week 4, Week 8, Week 12, Week 16
Photostress recovery time
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16
An ophthalmoscope will be used to shine a light into the participants eye for 10 seconds, and participants will be required to read letters off a chart the moment their vision returns to normal. The faster the recovery time, the better the outcome. Units will be in seconds
Week 0, Week 4, Week 8, Week 12, Week 16
Visual function questionnaire 25
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16
A questionnaire to for participants to self-evaluate their perception of their current eye health based on general vision, ocular pain, near activities, distance activities, vision specific functions, driving, color vision and peripheral vision. The best possible score is 100 and worst possible score is 0.
Week 0, Week 4, Week 8, Week 12, Week 16
Skin advanced glycation end products levels
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16
Measurement of skin advanced glycation end products level using a skin autofluorescence device, where participants wlll be instructed to place their forearm over the device and a light will be shone and a reading can be captured by detecting fluorescence. The results will be presented as arbitrary units.
Week 0, Week 4, Week 8, Week 12, Week 16
Dietary advanced glycation end products level
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16
Participants will be instructed to record down 3-day food records, from Thursday to Saturday, before each clinical visit. This will be used to estimate their advanced glycation end products intake from food by referring to existing nutrient databases. Units will be based on a common advanced glycation end product measured, carboxymethyllysine (CML), thus the unit will be mg CML/ kg food
Week 0, Week 4, Week 8, Week 12, Week 16
Blood advanced glycation end products levels
Time Frame: Week 0, Week 8 and Week 16
Participants will have their blood drawn by medical professionals at the Occupational Health Clinic. The blood will be processed and stored. Measurements will be done using ultra-performance liquid chromatography coupled with mass spectrometry techniques to determine the levels of advanced glycation end products. Units will be in μg/mL.
Week 0, Week 8 and Week 16
Contrast sensitivity
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16
Participants will read out letters on a ETDRS LogMAR chart at a fixed distance, where the letters differs in lightness to test participants' sensitivity to contrast. Tests results will be recorded in number of letters read, where the more letters the better the outcome.
Week 0, Week 4, Week 8, Week 12, Week 16

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Concentration of tumour necrosis factor-α
Time Frame: Week 0, Week 8, Week 16
The blood obtained from the participants will be processed for storage. Tumor necrosis factor-α results will be presented in ng/L according to the commercially available enzyme-linked immunosorbent assay kits.
Week 0, Week 8, Week 16
Concentration of interleukin-6
Time Frame: Week 0, Week 8, Week 16
The blood obtained from the participants will be processed for storage. Interleukin-6 results will be presented in ng/L according to the commercially available enzyme-linked immunosorbent assay kits.
Week 0, Week 8, Week 16
Concentration of high-sensitivity C-reactive protein
Time Frame: Week 0, Week 8, Week 16
The blood obtained from the participants will be processed for storage. Analyses of inflammation markers include tumor necrosis factor-α, interleukin-6. high sensitivity C-reactive protein. Tumor necrosis factor-α and interleukin-6 results will be presented in ng/L according to the commercially available enzyme-linked immunosorbent assay kits. High-sensitivity C-reactive protein results will be obtained and presented in mg/L by commercial lab testing.
Week 0, Week 8, Week 16
Concentration of fasting blood glucose
Time Frame: Week 0, Week 8, Week 16
Fasting blood glucose will be measured using commercial lab testing using participants' blood, units will be in mmol/L.
Week 0, Week 8, Week 16
Concentration of malondialdehyde
Time Frame: Week 0, Week 8, Week 16
The blood obtained from the participants will be processed for storage. Analyses of malondialdehyde using commercially available enzyme-linked immunosorbent assay kits. Units for malondialdehyde will be in ng/L according to assay kit instructions.
Week 0, Week 8, Week 16
Concentration of 8-isoprostaglandin-F2α
Time Frame: Week 0, Week 8, Week 16
The blood obtained from the participants will be processed for storage. Analyses of 8-isoprostaglandin-F2α using commercially available enzyme-linked immunosorbent assay kits. Units for 8-isoprostaglandin-F2α will be in µmol/L according to assay kit instructions.
Week 0, Week 8, Week 16
Skin carotenoid status
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16;
Measured using a commercially available device that measured carotenoids using Raman spectroscopy. Results are in arbitrary units.
Week 0, Week 4, Week 8, Week 12, Week 16;
Concentration of insulin
Time Frame: Week 0, Week 8, Week 16
Fasting blood insulin will be measured using commercial lab testing using participants' blood, units in μU/L.
Week 0, Week 8, Week 16
Percentage of glycated hemoglobin
Time Frame: Week 0, Week 8, Week 16
Glycated hemoglobin will be measured using commercial lab testing from participant's blood, units in percent.
Week 0, Week 8, Week 16

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Measurement of height
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16
Height will be measured using height-weight scale and units will be in cm.
Week 0, Week 4, Week 8, Week 12, Week 16
Measurement of blood pressure
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16
A blood pressure monitoring device available commercially will be used be to measure their systolic nad diastolic blood pressure.
Week 0, Week 4, Week 8, Week 12, Week 16
Measurement of weight
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16
Weight will be measured using height-weight scale and units will be in kg.
Week 0, Week 4, Week 8, Week 12, Week 16
Measurement of waist circumference
Time Frame: Week 0, Week 4, Week 8, Week 12, Week 16
Waist circumference will be measured using a measuring tape by a trained personnel, units in cm.
Week 0, Week 4, Week 8, Week 12, Week 16

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
National University of Singapore

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
California Table Grape Commission

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Jung Eun Kim, Ph.D., R.D., National University of Singapore

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 30, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
August 1, 2025

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 1, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 14, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 4, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 5, 2024

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 14, 2024

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 12, 2024

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2024

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • S25

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Electronic copies of the data with identifiable participant information will be kept on NUS OneDrive with access limited only Dr Kim Jung Eun and her research staff. All data will be de-identified prior to statistical analyses.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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