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

National University of Singapore46 enrolled

Overview

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.

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

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

DOUBLE

Enrollment

Conditions

Macula; Degeneration Aging Advanced Glycation End Products

Interventions

Freeze-dried table grape powderDIETARY_SUPPLEMENT

Consumption of grape powder as part of daily diet

Placebo grape powderDIETARY_SUPPLEMENT

Consumption of placebo grape powder as part of daily diet

Eligibility

Sex: ALLMin age: 60 YearsMax age: 85 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Locations (1)

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

Singapore, Singapore, Singapore

RECRUITING

Outcomes

Primary Outcomes

Macular pigment optical density

A measurement of macular pigment of the eye using a heterochromatic flicker photometry device. The measurements are in arbitrary units.

Time frame: 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.

Time frame: 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

Time frame: 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.

Time frame: 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.

Time frame: Week 0, Week 4, Week 8, Week 12, Week 16

Dietary advanced glycation end products level

Central Contacts

Marcus Ting

CONTACT

97851245 marcusting@u.nus.edu

Data from ClinicalTrials.gov

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Secondary Outcomes

Concentration of tumour necrosis factor-α

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.