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

National University of Singapore34 enrolled

Overview

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.

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

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

DOUBLE

Enrollment

Conditions

Eye Health Age-related Macular Degeneration

Interventions

Freeze-dried table grape powderDIETARY_SUPPLEMENT

Consumption of 46g/day freeze-dried table grape powder

Placebo of the table grape powderDIETARY_SUPPLEMENT

Consumption of 46g/day placebo version of the freeze-dried table grape powder

Eligibility

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

Medical Language ↔ Plain English

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

Locations (1)

National University of Singapore

Singapore, Singapore

Outcomes

Primary Outcomes

Change in macular pigment optical density

Macular pigment optical density will be measured using macular pigment scanner

Time frame: Every four weeks (week 0, week 4, week 8, week 12, week 16)

Change in skin carotenoid status

Skin carotenoid status (a.u) measured using NuSkin II, resonance Raman spectroscopy

Time frame: Every four weeks (week 0, week 4, week 8, week 12, week 16)

Change in blood carotenoid concentration

Blood carotenoid concentration to be quantified by HPLC

Time frame: Every eight weeks (week 0, week 8, week 16)

Secondary Outcomes

Change in flow mediate dilation

Flow mediate dilation (%)

Time frame: week 0 and week 16

Change in endothelial function

Endothelial functions are determined by the function of endothelial progenitor cells

Time frame: week 0 and week 16

Change in the concentration if Endothelin-1 in plasma

Endothelin-1 concentration

Time frame: week 0 and week 16

Change in the concentration if Nitric Oxide in plasma

Nitric Oxide concentration

Time frame: week 0 and week 16

Change in body weight

Body weight (kg) measured using body scale

Time frame: Every four weeks (week 0, week 4, week 8, week 12, week 16)

Data from ClinicalTrials.gov

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