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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Eye Health, Age-related Macular Degeneration

Intervention / Treatment
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* Dietary Supplement: Freeze-dried table grape powder
* Dietary Supplement: Placebo of the table grape powder


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 60 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Freeze-dried table grape powder<br>The intervention group will consume 46 g/day of a freeze-dried table grape powder. | Dietary Supplement: Freeze-dried table grape powder<br>* Consumption of 46g/day freeze-dried table grape powder<br>|
| Placebo Comparator: Placebo grape powder<br>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<br>* Consumption of 46g/day placebo version of the freeze-dried table grape powder<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in macular pigment optical density | 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 | 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 | Blood carotenoid concentration to be quantified by HPLC | Every eight weeks (week 0, week 8, week 16) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in flow mediate dilation | Flow mediate dilation (%) | week 0 and week 16 | 
| Change in endothelial function | 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 | Endothelin-1 concentration | week 0 and week 16 | 
| Change in the concentration if Nitric Oxide in plasma | Nitric Oxide concentration | week 0 and week 16 | 
| Change in body weight | Body weight (kg) measured using body scale | Every four weeks (week 0, week 4, week 8, week 12, week 16) | 
| Change in BMI | 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 | 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 | 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 | Malondialdehyde concentration | Every eight weeks (week 0, week 8, week 16) | 
| Change in the concentration of 8-iso-prostaglandin F2α in plasma | 8-iso-prostaglandin F2α concentration | Every eight weeks (week 0, week 8, week 16) | 
| Change in blood glucose concentration | Blood glucose concentration (mmol/l) | Every eight weeks (week 0, week 8, week 16) | 
| Change in total cholesterol | Total cholesterol (mmol/l) | Every eight weeks (week 0, week 8, week 16) | 
| Change in high-density lipoprotein cholesterol | High-density lipoprotein cholesterol (mmol/l) | Every eight weeks (week 0, week 8, week 16) | 
| Change in low-density lipoprotein cholesterol | Low-density lipoprotein cholesterol (mmol/l) | Every eight weeks (week 0, week 8, week 16) | 
| Change in total triglyceride | Total triglyceride (mmol/l) | Every eight weeks (week 0, week 8, week 16) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Eye Health, Age-related Macular Degeneration, carotenoids