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

Age-related Macular Degeneration Clinical Trial

Official title:

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

Clinical Trial Details — Status: Active, not recruiting

Administrative data

• NCT number: NCT05064865
• Other study ID #: S15
• Status: Active, not recruiting
• Phase: N/A
• Start date: January 28, 2022
• Est. completion date: October 2024

Study information

• Verified date: November 2023
• Source: National University of Singapore
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Active, not recruiting
• Enrollment: 34
• Est. completion date: October 2024
• Est. primary completion date: August 31, 2022
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 60 Years to 85 Years

Eligibility

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

Related Conditions & MeSH terms

• Age-related Macular Degeneration
• Eye Health
• Macular Degeneration

Intervention

Dietary Supplement:
• Freeze-dried table grape powder
Consumption of 46g/day freeze-dried table grape powder
• Placebo of the table grape powder
Consumption of 46g/day placebo version of the freeze-dried table grape powder

Locations

Country	Name	City	State
Singapore	National University of Singapore	Singapore

Sponsors (3)

Lead Sponsor	Collaborator
National University of Singapore	Ministry of Education, Singapore, National University Hospital, Singapore

Country where clinical trial is conducted

Singapore, 

References & Publications (1)

Gehrs KM, Anderson DH, Johnson LV, Hageman GS. Age-related macular degeneration--emerging pathogenetic and therapeutic concepts. Ann Med. 2006;38(7):450-71. doi: 10.1080/07853890600946724. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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)
Primary	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)
Primary	Change in blood carotenoid concentration	Blood carotenoid concentration to be quantified by HPLC	Every eight weeks (week 0, week 8, week 16)
Secondary	Change in flow mediate dilation	Flow mediate dilation (%)	week 0 and week 16
Secondary	Change in endothelial function	Endothelial functions are determined by the function of endothelial progenitor cells	week 0 and week 16
Secondary	Change in the concentration if Endothelin-1 in plasma	Endothelin-1 concentration	week 0 and week 16
Secondary	Change in the concentration if Nitric Oxide in plasma	Nitric Oxide concentration	week 0 and week 16
Secondary	Change in body weight	Body weight (kg) measured using body scale	Every four weeks (week 0, week 4, week 8, week 12, week 16)
Secondary	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)
Secondary	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)
Secondary	change in waist circumference	Waist circumference (cm) measured using measuring tape	Every four weeks (week 0, week 4, week 8, week 12, week 16)
Secondary	Change in the concentration of malondialdehyde in plasma	Malondialdehyde concentration	Every eight weeks (week 0, week 8, week 16)
Secondary	Change in the concentration of 8-iso-prostaglandin F2a in plasma	8-iso-prostaglandin F2a concentration	Every eight weeks (week 0, week 8, week 16)
Secondary	Change in blood glucose concentration	Blood glucose concentration (mmol/l)	Every eight weeks (week 0, week 8, week 16)
Secondary	Change in total cholesterol	Total cholesterol (mmol/l)	Every eight weeks (week 0, week 8, week 16)
Secondary	Change in high-density lipoprotein cholesterol	High-density lipoprotein cholesterol (mmol/l)	Every eight weeks (week 0, week 8, week 16)
Secondary	Change in low-density lipoprotein cholesterol	Low-density lipoprotein cholesterol (mmol/l)	Every eight weeks (week 0, week 8, week 16)
Secondary	Change in total triglyceride	Total triglyceride (mmol/l)	Every eight weeks (week 0, week 8, week 16)