Clinical trial NCT06349304: Impact of Grape Powder Consumption on Eye Health and Glycemic Status in Singapore Older Adults
Official title: Impact of Regular Consumption of Grape on Eye Health and Regulation of Advanced Glycation End-products in Singapore Older Adults
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Macula; Degeneration
Aging
Advanced Glycation End Products
Keywords: Vitis vinifera
Older adults
Inflammation
Glycemic status
Oxidative stress
Eye health
Lead sponsor: National University of Singapore
Sponsor class: OTHER
Collaborators: name: California Table Grape Commission
First posted: 2024-04-05
Enrollment: 46
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: 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.

Detailed description: 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.

Eligibility criteria: 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

Primary outcomes:
measure: Macular pigment optical density
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16
measure: Visual acuity
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16
measure: Photostress recovery time
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16
measure: Visual function questionnaire 25
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16
measure: Skin advanced glycation end products levels
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16
measure: Dietary advanced glycation end products level
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16
measure: Blood advanced glycation end products levels
timeFrame: Week 0, Week 8 and Week 16
measure: Contrast sensitivity
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16
Secondary outcomes:
measure: Concentration of tumour necrosis factor-α
timeFrame: Week 0, Week 8, Week 16
measure: Concentration of interleukin-6
timeFrame: Week 0, Week 8, Week 16
measure: Concentration of high-sensitivity C-reactive protein
timeFrame: Week 0, Week 8, Week 16
measure: Concentration of fasting blood glucose
timeFrame: Week 0, Week 8, Week 16
measure: Concentration of malondialdehyde
timeFrame: Week 0, Week 8, Week 16
measure: Concentration of 8-isoprostaglandin-F2α
timeFrame: Week 0, Week 8, Week 16
measure: Skin carotenoid status
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16;
measure: Concentration of insulin
timeFrame: Week 0, Week 8, Week 16
measure: Percentage of glycated hemoglobin
timeFrame: Week 0, Week 8, Week 16
Other outcomes:
measure: Measurement of height
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16
measure: Measurement of blood pressure
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16
measure: Measurement of weight
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16
measure: Measurement of waist circumference
timeFrame: Week 0, Week 4, Week 8, Week 12, Week 16
Locations:
city: Singapore
country: Singapore
facility: National University of Singapore, Faculty of Science, Department of Food Science and Technology
Study officials:
affiliation: National University of Singapore
name: Jung Eun Kim, Ph.D., R.D.
role: PRINCIPAL_INVESTIGATOR
References:
citation: Hu W, Zheng R, Feng Y, Tan D, Chan Chung-Tsing G, Su X, Kim JE. Impacts of regular consumption of grapes on macular pigment accumulation in Singapore older adults: a randomized controlled trial. Food Funct. 2023 Sep 19;14(18):8321-8330. doi: 10.1039/d3fo02105j.