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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT05064865
Recruitment Status : Recruiting
First Posted : October 1, 2021
Last Update Posted : March 31, 2022
Sponsor:
Collaborators:
National University Hospital, Singapore
Ministry of Education, Singapore
Information provided by (Responsible Party):
Jung Eun Kim, National University, Singapore

Brief Summary:
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.

Condition or disease Intervention/treatment Phase
Eye Health Age-related Macular Degeneration Dietary Supplement: Freeze-dried table grape powder Dietary Supplement: Placebo of the table grape powder Not Applicable

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.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 38 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Prevention
Official Title: Impact of Regular Consumption of Grapes on Eye Health in Singapore Older Adults
Actual Study Start Date : January 28, 2022
Estimated Primary Completion Date : April 2023
Estimated Study Completion Date : October 2023

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
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




Primary Outcome Measures :
  1. 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

  2. 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

  3. Change in blood carotenoid concentration [ Time Frame: Every eight weeks (week 0, week 8, week 16) ]
    Blood carotenoid concentration to be quantified by HPLC


Secondary Outcome Measures :
  1. Change in flow mediate dilation [ Time Frame: week 0 and week 16 ]
    Flow mediate dilation (%)

  2. Change in endothelial function [ Time Frame: week 0 and week 16 ]
    Endothelial functions are determined by the function of endothelial progenitor cells

  3. Change in the concentration if Endothelin-1 in plasma [ Time Frame: week 0 and week 16 ]
    Endothelin-1 concentration

  4. Change in the concentration if Nitric Oxide in plasma [ Time Frame: week 0 and week 16 ]
    Nitric Oxide concentration

  5. 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

  6. 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

  7. 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

  8. 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

  9. Change in the concentration of malondialdehyde in plasma [ Time Frame: Every eight weeks (week 0, week 8, week 16) ]
    Malondialdehyde concentration

  10. 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

  11. Change in blood glucose concentration [ Time Frame: Every eight weeks (week 0, week 8, week 16) ]
    Blood glucose concentration (mmol/l)

  12. Change in total cholesterol [ Time Frame: Every eight weeks (week 0, week 8, week 16) ]
    Total cholesterol (mmol/l)

  13. Change in high-density lipoprotein cholesterol [ Time Frame: Every eight weeks (week 0, week 8, week 16) ]
    High-density lipoprotein cholesterol (mmol/l)

  14. Change in low-density lipoprotein cholesterol [ Time Frame: Every eight weeks (week 0, week 8, week 16) ]
    Low-density lipoprotein cholesterol (mmol/l)

  15. Change in total triglyceride [ Time Frame: Every eight weeks (week 0, week 8, week 16) ]
    Total triglyceride (mmol/l)



Information from the National Library of Medicine

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Ages Eligible for Study:   60 Years to 85 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT05064865


Contacts
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Contact: Weili Hu 80393103 weili.hu@u.nus.edu

Locations
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Singapore
National University of Singapore Recruiting
Singapore, Singapore, 117546
Contact: Weili Hu    80393103    weili.hu@u.nus.edu   
Sponsors and Collaborators
National University, Singapore
National University Hospital, Singapore
Ministry of Education, Singapore
Investigators
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Principal Investigator: Jung Eun Kim National University, Singapore
Publications:
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Responsible Party: Jung Eun Kim, Assistant Professor, National University, Singapore
ClinicalTrials.gov Identifier: NCT05064865    
Other Study ID Numbers: S15
First Posted: October 1, 2021    Key Record Dates
Last Update Posted: March 31, 2022
Last Verified: March 2022
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Plan Description: Electronic copies of the data with identifiable participant information will be key data will be de-identified prior to statistical analysis

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Jung Eun Kim, National University, Singapore:
Eye Health
Age-related Macular Degeneration
carotenoids
Additional relevant MeSH terms:
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Macular Degeneration
Retinal Degeneration
Retinal Diseases
Eye Diseases