Clinical trial NCT05064865: Impact of Regular Consumption of Grapes on Eye Health in Singapore Older Adults
Official title: Impact of Regular Consumption of Grapes on Eye Health in Singapore Older Adults
Study type: INTERVENTIONAL
Overall status: ACTIVE_NOT_RECRUITING
Phase: NA
Conditions: Eye Health
Age-related Macular Degeneration
Keywords: Eye Health
Age-related Macular Degeneration
carotenoids
Lead sponsor: National University of Singapore
Sponsor class: OTHER
Collaborators: name: National University Hospital, Singapore
name: Ministry of Education, Singapore
First posted: 2021-10-01
Enrollment: 34
Sex: ALL
Minimum age (years): 60
Maximum age (years): 85
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief 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.

Detailed 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.

Eligibility criteria: 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

Primary outcomes:
measure: Change in macular pigment optical density
timeFrame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
measure: Change in skin carotenoid status
timeFrame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
measure: Change in blood carotenoid concentration
timeFrame: Every eight weeks (week 0, week 8, week 16)
Secondary outcomes:
measure: Change in flow mediate dilation
timeFrame: week 0 and week 16
measure: Change in endothelial function
timeFrame: week 0 and week 16
measure: Change in the concentration if Endothelin-1 in plasma
timeFrame: week 0 and week 16
measure: Change in the concentration if Nitric Oxide in plasma
timeFrame: week 0 and week 16
measure: Change in body weight
timeFrame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
measure: Change in BMI
timeFrame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
measure: Change in blood pressure
timeFrame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
measure: change in waist circumference
timeFrame: Every four weeks (week 0, week 4, week 8, week 12, week 16)
measure: Change in the concentration of malondialdehyde in plasma
timeFrame: Every eight weeks (week 0, week 8, week 16)
measure: Change in the concentration of 8-iso-prostaglandin F2α in plasma
timeFrame: Every eight weeks (week 0, week 8, week 16)
measure: Change in blood glucose concentration
timeFrame: Every eight weeks (week 0, week 8, week 16)
measure: Change in total cholesterol
timeFrame: Every eight weeks (week 0, week 8, week 16)
measure: Change in high-density lipoprotein cholesterol
timeFrame: Every eight weeks (week 0, week 8, week 16)
measure: Change in low-density lipoprotein cholesterol
timeFrame: Every eight weeks (week 0, week 8, week 16)
measure: Change in total triglyceride
timeFrame: Every eight weeks (week 0, week 8, week 16)
Other outcomes:
Locations:
city: Singapore
country: Singapore
facility: National University of Singapore
Study officials:
affiliation: National University of Singapore
name: Jung Eun Kim
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.