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| Name | Class |
|---|---|
| California Table Grape Commission | OTHER |
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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.
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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Freeze-dried table grape powder | Experimental | Subjects in this group will be given pouches, each containing 46 g of freeze-dried table grape powder, with an instruction sheet on how to prepare the powder into a drink for consumption.They will consume one pouch a day. |
|
| Placebo table grape powder | Placebo Comparator | Subjects in this group will be given pouches, each containing 46 g of placebo grape powder, with an instruction sheet on how to prepare the powder into a drink for consumption.They will consume one pouch a day. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Freeze-dried table grape powder | Dietary Supplement | Consumption of grape powder as part of daily diet |
|
| Measure | Description | Time Frame |
|---|---|---|
| Macular pigment optical density | A measurement of macular pigment of the eye using a heterochromatic flicker photometry device. The measurements are in arbitrary units. | Week 0, Week 4, Week 8, Week 12, Week 16 |
| Visual acuity | Participants will read out letters on a ETDRS LogMAR chart at a fixed distance where letters becomes smaller as it goes down the chart. Tests results will be recorded in number of letters read, where the more letters the better the outcome. | Week 0, Week 4, Week 8, Week 12, Week 16 |
| Photostress recovery time | An ophthalmoscope will be used to shine a light into the participants eye for 10 seconds, and participants will be required to read letters off a chart the moment their vision returns to normal. The faster the recovery time, the better the outcome. Units will be in seconds | Week 0, Week 4, Week 8, Week 12, Week 16 |
| Visual function questionnaire 25 | A questionnaire to for participants to self-evaluate their perception of their current eye health based on general vision, ocular pain, near activities, distance activities, vision specific functions, driving, color vision and peripheral vision. The best possible score is 100 and worst possible score is 0. | Week 0, Week 4, Week 8, Week 12, Week 16 |
| Skin advanced glycation end products levels | Measurement of skin advanced glycation end products level using a skin autofluorescence device, where participants wlll be instructed to place their forearm over the device and a light will be shone and a reading can be captured by detecting fluorescence. The results will be presented as arbitrary units. | Week 0, Week 4, Week 8, Week 12, Week 16 |
| Measure | Description | Time Frame |
|---|---|---|
| Concentration of tumour necrosis factor-α | The blood obtained from the participants will be processed for storage. Tumor necrosis factor-α results will be presented in ng/L according to the commercially available enzyme-linked immunosorbent assay kits. | Week 0, Week 8, Week 16 |
| Concentration of interleukin-6 |
| Measure | Description | Time Frame |
|---|---|---|
| Measurement of height | Height will be measured using height-weight scale and units will be in cm. | Week 0, Week 4, Week 8, Week 12, Week 16 |
| Measurement of blood pressure | A blood pressure monitoring device available commercially will be used be to measure their systolic nad diastolic blood pressure. |
Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Marcus Ting | Contact | 97851245 | marcusting@u.nus.edu |
| Name | Affiliation | Role |
|---|---|---|
| Jung Eun Kim, Ph.D., R.D. | National University of Singapore | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| National University of Singapore, Faculty of Science, Department of Food Science and Technology | Recruiting | Singapore | Singapore | 117550 | Singapore |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 37605542 | Background | 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. |
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Electronic copies of the data with identifiable participant information will be kept on NUS OneDrive with access limited only Dr Kim Jung Eun and her research staff. All data will be de-identified prior to statistical analyses.
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| ID | Term |
|---|---|
| D007249 | Inflammation |
| ID | Term |
|---|---|
| D010335 | Pathologic Processes |
| D013568 | Pathological Conditions, Signs and Symptoms |
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| Placebo grape powder | Dietary Supplement | Consumption of placebo grape powder as part of daily diet |
|
| Dietary advanced glycation end products level | Participants will be instructed to record down 3-day food records, from Thursday to Saturday, before each clinical visit. This will be used to estimate their advanced glycation end products intake from food by referring to existing nutrient databases. Units will be based on a common advanced glycation end product measured, carboxymethyllysine (CML), thus the unit will be mg CML/ kg food | Week 0, Week 4, Week 8, Week 12, Week 16 |
| Blood advanced glycation end products levels | Participants will have their blood drawn by medical professionals at the Occupational Health Clinic. The blood will be processed and stored. Measurements will be done using ultra-performance liquid chromatography coupled with mass spectrometry techniques to determine the levels of advanced glycation end products. Units will be in μg/mL. | Week 0, Week 8 and Week 16 |
| Contrast sensitivity | Participants will read out letters on a ETDRS LogMAR chart at a fixed distance, where the letters differs in lightness to test participants' sensitivity to contrast. Tests results will be recorded in number of letters read, where the more letters the better the outcome. | Week 0, Week 4, Week 8, Week 12, Week 16 |
The blood obtained from the participants will be processed for storage. Interleukin-6 results will be presented in ng/L according to the commercially available enzyme-linked immunosorbent assay kits. |
| Week 0, Week 8, Week 16 |
| Concentration of high-sensitivity C-reactive protein | The blood obtained from the participants will be processed for storage. Analyses of inflammation markers include tumor necrosis factor-α, interleukin-6. high sensitivity C-reactive protein. Tumor necrosis factor-α and interleukin-6 results will be presented in ng/L according to the commercially available enzyme-linked immunosorbent assay kits. High-sensitivity C-reactive protein results will be obtained and presented in mg/L by commercial lab testing. | Week 0, Week 8, Week 16 |
| Concentration of fasting blood glucose | Fasting blood glucose will be measured using commercial lab testing using participants' blood, units will be in mmol/L. | Week 0, Week 8, Week 16 |
| Concentration of malondialdehyde | The blood obtained from the participants will be processed for storage. Analyses of malondialdehyde using commercially available enzyme-linked immunosorbent assay kits. Units for malondialdehyde will be in ng/L according to assay kit instructions. | Week 0, Week 8, Week 16 |
| Concentration of 8-isoprostaglandin-F2α | The blood obtained from the participants will be processed for storage. Analyses of 8-isoprostaglandin-F2α using commercially available enzyme-linked immunosorbent assay kits. Units for 8-isoprostaglandin-F2α will be in µmol/L according to assay kit instructions. | Week 0, Week 8, Week 16 |
| Skin carotenoid status | Measured using a commercially available device that measured carotenoids using Raman spectroscopy. Results are in arbitrary units. | Week 0, Week 4, Week 8, Week 12, Week 16; |
| Concentration of insulin | Fasting blood insulin will be measured using commercial lab testing using participants' blood, units in μU/L. | Week 0, Week 8, Week 16 |
| Percentage of glycated hemoglobin | Glycated hemoglobin will be measured using commercial lab testing from participant's blood, units in percent. | Week 0, Week 8, Week 16 |
| Week 0, Week 4, Week 8, Week 12, Week 16 |
| Measurement of weight | Weight will be measured using height-weight scale and units will be in kg. | Week 0, Week 4, Week 8, Week 12, Week 16 |
| Measurement of waist circumference | Waist circumference will be measured using a measuring tape by a trained personnel, units in cm. | Week 0, Week 4, Week 8, Week 12, Week 16 |