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

NCT06349304 | Recruiting

• 1 other identifier: S25
• Study Type: interventional
• Target: 46
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Macula; Degeneration; Aging; Advanced Glycation End Products

Keywords

Vitis vinifera; Older adults; Inflammation; Glycemic status; Oxidative stress; Eye health

Outcome Measures

Primary Outcomes (8)

• Macular pigment optical density

  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

  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

  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

  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

  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

  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

  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

  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 Outcomes (9)

• Concentration of tumour necrosis factor-α

  Week 0, Week 8, Week 16

• Concentration of interleukin-6

  Week 0, Week 8, Week 16

• Concentration of high-sensitivity C-reactive protein

  Week 0, Week 8, Week 16

• Concentration of fasting blood glucose

  Week 0, Week 8, Week 16

• Concentration of malondialdehyde

  Week 0, Week 8, Week 16

Other Outcomes (4)

• Measurement of height

  Week 0, Week 4, Week 8, Week 12, Week 16

• Measurement of blood pressure

  Week 0, Week 4, Week 8, Week 12, Week 16

• Measurement of weight

  Week 0, Week 4, Week 8, Week 12, Week 16

Study Arms (2)

Freeze-dried table grape powder

EXPERIMENTAL

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

Placebo table grape powder

PLACEBO COMPARATOR

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

Interventions

Freeze-dried table grape powder DIETARY_SUPPLEMENT

Consumption of grape powder as part of daily diet

Freeze-dried table grape powder

Placebo grape powder DIETARY_SUPPLEMENT

Consumption of placebo grape powder as part of daily diet

Placebo table grape powder

Eligibility Criteria

• Age: 60 Years - 85 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

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

You may not qualify if:

• Smokers
• Allergy to grapes or food dyes/additives, or had serious food allergies in the past
• Known eye diseases (macular degeneration, cataracts, retinopathy or glaucoma), blindness in at least one eye or have had eye surgery
• Unable to view bright lights or flashing lights
• Has Type 1 or 2 diabetes, uremia, cardiovascular disease, abnormal kidney and liver function
• Taking eye medication and/or dietary supplements for the eyes for the past 3 month
• Taking supplements containing carotenoids (e.g. Vitamin A, lutein, zeaxanthin) for past 3 months
• Currently on a specialised 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
• Currently on anti-hypertensive, cholesterol-lowering or psychoactive drugs
• Scored ≤ 7 on the abbreviated mental test
• Poor peripheral venous access based on past experiences with blood draw
• Participating in another clinical study

Sponsors & Collaborators

• National University of Singapore: lead
• California Table Grape Commission: collaborator

Study Sites (1)

National University of Singapore, Faculty of Science, Department of Food Science and Technology

Singapore, Singapore, 117550, Singapore

RECRUITING

Related Publications (1)

• Hu W, Zheng R, Feng Y, Tan D, Chan Chung-Tsing G, Su X, Kim JE. Impacts of regular consumption of grapes on macular pigment accumulation in Singapore older adults: a randomized controlled trial. Food Funct. 2023 Sep 19;14(18):8321-8330. doi: 10.1039/d3fo02105j.

  PMID: 37605542 BACKGROUND

MeSH Terms

Conditions

Inflammation

Condition Hierarchy (Ancestors)

Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Jung Eun Kim, Ph.D., R.D.

  National University of Singapore

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Marcus Ting

CONTACT

97851245; marcusting@u.nus.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: March 14, 2024
• First Posted: April 5, 2024
• Study Start: September 30, 2024
• Primary Completion: August 1, 2025
• Study Completion: August 1, 2025
• Last Updated: November 14, 2024

Record last verified: 2024-04

Data Sharing

• IPD Sharing: Will not share

Locations

SG (1)