Impact of Regular Consumption of Grapes on Eye Health in Singapore Older Adults

November 7, 2023 updated by: Jung Eun Kim, National University of Singapore
Aging epidemics in Singapore are rapidly increasing and Age-related macular degeneration (AMD) prevalence is significantly associated with older age. This study aims to understand the effect of consuming freeze-dried table grape powder on AMD in an older population.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not 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

This will be carried out through a 16-week double-blind, randomized, placebo-controlled trial of parallel study design. Thirty-eight men and women (aged between 60 and 85 years old inclusive) will recruited and assigned to an intervention or placebo group. The intervention group will consume 46 g/day of a freeze-dried table grape and the control group will consume the same amount of a placebo, table grape placebo powder. Measurements of 1) macular pigment optical density (MPOD), a clinical marker for eye health, 2) carotenoids status, 3) markers of oxidative stress, 4) markers of endothelial function, 5) body size and blood pressure, and 6) dietary assessment will be assessed over the 16-week study. This study will consist of 1 screening visit and 5 study visits in 4-week intervals to the Food Science and Technology Department, Occupational Health Clinic and National University Heart Centre.

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 (Actual)

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.
34

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, 117546
        • National University of Singapore

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

60 years to 85 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Male and female participants, aged between 60 and 85 years old inclusive
  • Able to give informed consent in English

Exclusion Criteria:

  • Smokers
  • Allergy to grapes
  • Known eye diseases (macular degeneration, cataracts, retinopathy or glaucoma), blindness in at least one eye or have had eye surgery
  • Abnormal kidney and liver function
  • Taking eye medication and/or dietary supplements for the eyes for the past 3 months
  • Taking supplements containing carotenoids (e.g. Vitamin A, lutein, zeaxanthin) for the past 3 months
  • Currently on type 2 diabetic medication.
  • Currently on anti-hypertensive or cholesterol-lowering; unless this prescription has been ongoing for more than 3 years prior to study participation.
  • Currently on a specialized diet (e.g. vegetarian, vegan, weight loss diet, low fat diet)
  • 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.
  • Significant change in weight (≥ 3 kg body weight) in the past 3 months
  • Significant exercise pattern over the past 3 months defined as high-intensity exercise of more than 3 hours per week
  • Poor peripheral venous access based on past experiences with blood draw
  • 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
The intervention group will consume 46 g/day of a freeze-dried table grape powder.
Dietary supplement: Freeze-dried table grape powder
Consumption of 46g/day freeze-dried table grape powder
Placebo Comparator: Placebo grape powder
The control group will consume the same amount of a placebo with a similar taste to the table grape powder.
Dietary supplement: Placebo of the table grape powder
Consumption of 46g/day placebo version of the freeze-dried table grape powder

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
Change in macular pigment optical density
Time Frame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
Macular pigment optical density will be measured using macular pigment scanner
Every four weeks (week 0, week 4, week 8, week 12, week 16)
Change in skin carotenoid status
Time Frame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
Skin carotenoid status (a.u) measured using NuSkin II, resonance Raman spectroscopy
Every four weeks (week 0, week 4, week 8, week 12, week 16)
Change in blood carotenoid concentration
Time Frame: Every eight weeks (week 0, week 8, week 16)
Blood carotenoid concentration to be quantified by HPLC
Every eight weeks (week 0, week 8, 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
Change in flow mediate dilation
Time Frame: week 0 and week 16
Flow mediate dilation (%)
week 0 and week 16
Change in endothelial function
Time Frame: week 0 and week 16
Endothelial functions are determined by the function of endothelial progenitor cells
week 0 and week 16
Change in the concentration if Endothelin-1 in plasma
Time Frame: week 0 and week 16
Endothelin-1 concentration
week 0 and week 16
Change in the concentration if Nitric Oxide in plasma
Time Frame: week 0 and week 16
Nitric Oxide concentration
week 0 and week 16
Change in body weight
Time Frame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
Body weight (kg) measured using body scale
Every four weeks (week 0, week 4, week 8, week 12, week 16)
Change in BMI
Time Frame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
Weight and height will be combined to report BMI in kg/m^2
Every four weeks (week 0, week 4, week 8, week 12, week 16)
Change in blood pressure
Time Frame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
Systolic and diastolic blood pressure (mmHg) measured using sphygmomanometer
Every four weeks (week 0, week 4, week 8, week 12, week 16)
change in waist circumference
Time Frame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
Waist circumference (cm) measured using measuring tape
Every four weeks (week 0, week 4, week 8, week 12, week 16)
Change in the concentration of malondialdehyde in plasma
Time Frame: Every eight weeks (week 0, week 8, week 16)
Malondialdehyde concentration
Every eight weeks (week 0, week 8, week 16)
Change in the concentration of 8-iso-prostaglandin F2α in plasma
Time Frame: Every eight weeks (week 0, week 8, week 16)
8-iso-prostaglandin F2α concentration
Every eight weeks (week 0, week 8, week 16)
Change in blood glucose concentration
Time Frame: Every eight weeks (week 0, week 8, week 16)
Blood glucose concentration (mmol/l)
Every eight weeks (week 0, week 8, week 16)
Change in total cholesterol
Time Frame: Every eight weeks (week 0, week 8, week 16)
Total cholesterol (mmol/l)
Every eight weeks (week 0, week 8, week 16)
Change in high-density lipoprotein cholesterol
Time Frame: Every eight weeks (week 0, week 8, week 16)
High-density lipoprotein cholesterol (mmol/l)
Every eight weeks (week 0, week 8, week 16)
Change in low-density lipoprotein cholesterol
Time Frame: Every eight weeks (week 0, week 8, week 16)
Low-density lipoprotein cholesterol (mmol/l)
Every eight weeks (week 0, week 8, week 16)
Change in total triglyceride
Time Frame: Every eight weeks (week 0, week 8, week 16)
Total triglyceride (mmol/l)
Every eight weeks (week 0, week 8, 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.
National University Hospital, Singapore
Ministry of Education, Singapore

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, 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.
January 28, 2022

Primary Completion (Actual)

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 31, 2022

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.
October 1, 2024

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).
August 30, 2021

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.
September 23, 2021

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.
October 1, 2021

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 9, 2023

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 7, 2023

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.
November 1, 2023

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

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.
  • S15

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 key data will be de-identified prior to statistical analysis

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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