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| Name | Class |
|---|---|
| Dalhousie University | OTHER |
| U.S. Highbush Blueberry Council | OTHER |
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Clinical evidence for effects of plant anthocyanins on vision, and particularly night vision is controversial. Two clinical trials were conducted to investigate whether blueberry juice consumption affected visual dark adaptation, functional night vision, and recovery after photo-bleaching of the retina. One trial (S2) employed a 3 week intervention and washout period, and two doses of blueberries plus a placebo. The other trial (L1) employed a 12 week intervention plus an 8 week washout and tested one blueberry juice dose against a juice placebo.
Vision Tests: 1. Dark adaptometry, 2. scotopic visual acuity, 3. scotopic contrast sensitivity, 4. rod/cone conversion, 5. recovery after retinal photobleaching
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Blueberry Juice | Active Comparator | Commercially prepared single strength blueberry juice which was composed of a 50:50 blend of two highbush blueberry species (Vaccinium corymbosum L. 'Rubel' and V. ashei Reade 'TifBlue'). Volunteers consumed 300 mls of juice/day (247-271 mg anthocyanins (as C3G) daily) while on this intervention, for either 3 weeks (Blueberry Juice S2) or 12 weeks (Blueberry Juice L1). |
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| Blueberry Capsules | Active Comparator | Commercially prepared single strength blueberry juice which was composed of a 50:50 blend of two highbush blueberry species (Vaccinium corymbosum L. 'Rubel' and V. ashei Reade 'TifBlue')was freeze dried to a powder and encapsulated in gelatin capsules (Blueberry Capsules S2). Volunteers consumed 3 capsules/daily (7.11mg anthocyanin (as C3G eq) for 3 weeks. |
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| Placebo | Placebo Comparator | Volunteers consumed in S2 three placebo capsules daily for 3 weeks. In L1 volunteers consumed 300ml placebo juice for twelve weeks. Placebo products contained no anthocyanins. |
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| Washout (S2 and L1) | No Intervention | Washout periods involved no study products. Washout was 3 weeks in S2 and or 8 weeks (L1) in duration. |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Blueberry Juice S2 | Dietary Supplement | Blueberry Juice S2 was commercially prepared single strength blueberry juice composed of a 50:50 blend of Rubel (Vaccinium corymbosum L.) and Tifblue (Vaccinium ashei Reade) cultivars. Colorimetric analysis showed that S2 juice contained 6.04 (SD=0.20) mg anthocyanins (C3G) eq/g dry mass. |
| Measure | Description | Time Frame |
|---|---|---|
| Rate of vision adaptation to low light after blueberry juice and placebo ingestion for 3 weeks (S2). | Effect of blueberry products and placebo on the rate of vision adaptation to low light. The rate of vision adaptation is measured by lowest perceptible light intensity after 30 min of darkness (dark threshold); time to reach dark threshold (min); time to reach rod/cone transition (min) [Time Frame: Pre-intervention, after 3 weeks intervention, again after a 3 week washout.] [Designated as safety issue: No] | Pre-intervention, and changes after 3 weeks of intervention, and again after 3 weeks of washout |
| Rate of vision adaptation to low light after ingestion of blueberry juice and placebo for 12 weeks (L1). | Effect of blueberry products and placebo on the rate of vision adaptation to low light. The rate of vision adaptation is measured by lowest perceptible light intensity after 30 min of darkness (dark threshold); time to reach dark threshold (min); time to reach rod/cone transition (min) [Time Frame: Pre-intervention, after 8 and 12 weeks intervention, and again after 4 and 8 weeks washout] [Designated as safety issue: No] | Preintervention, and changes after 8 and 12 weeks of intervention and after 4 and 8 weeks of washout |
| Measure | Description | Time Frame |
|---|---|---|
| Rate of recovery of visual acuity after retinal photostress (S2). | After dark adaptation testing (primary outcome) and contrast sensitivity and visual acuity testing (other pre-specified outcome measures), participants are subjected to photostress of the retina using bright light. The time (sec) required to recover pre-stress acuity is measured. | Pre-intervention testing and testing for changes after 3 weeks of intervention and 3 weeks of washout |
| Measure | Description | Time Frame |
|---|---|---|
| Visual acuity and contrast sensitivity testing after dark adaptation (S2). | After dark adaptation testing (primary outcome measure) and before measuring rate of recovery from photo stress (secondary outcome) visual acuity in darkness and contrast sensitivity in darkness was measured using defined optotypes with different degrees of crowding and contrast. Performance was defined as the number of correct answers in 12 tests of acuity and 8 tests of contrast sensitivity. |
Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Wilhelmina Kalt, PhD | Agriculture and Agri-Food Canada | Principal Investigator |
| Francois Tremblay, PhD | Dalhousie University and IWK Health Center | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Atlantic Food and Horicultural Research Center | Kentville | Nova Scotia | B4N1J5 | Canada |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 25335781 | Derived | Kalt W, McDonald JE, Fillmore SA, Tremblay F. Blueberry effects on dark vision and recovery after photobleaching: placebo-controlled crossover studies. J Agric Food Chem. 2014 Nov 19;62(46):11180-9. doi: 10.1021/jf503689c. Epub 2014 Nov 6. |
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| ID | Term |
|---|---|
| D001766 | Blindness |
| D015354 | Vision, Low |
| ID | Term |
|---|---|
| D014786 | Vision Disorders |
| D012678 | Sensation Disorders |
| D009461 | Neurologic Manifestations |
| D009422 | Nervous System Diseases |
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| ID | Term |
|---|---|
| C000721609 | blueberry extract |
| D004837 | Epinephrine |
| ID | Term |
|---|---|
| D004983 | Ethanolamines |
| D000605 | Amino Alcohols |
| D000438 | Alcohols |
| D009930 | Organic Chemicals |
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| Blueberry Capsules S2 | Dietary Supplement | Commercially prepared single strength blueberry juice composed of a 50:50 blend of Rubel (Vaccinium corymbosum L.) and Tifblue (Vaccinium ashei Reade) cultivars was freeze dried then powdered and encapsulated in gelatin capsules. Colorimetric analysis indicated an anthocyanin concentration in the powder of 2.37(SD=0.18) mg C3G eq per capsule. |
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| Placebo Capsule S2 | Dietary Supplement | Placebo Capsule S2 (containing no anthocyanins) were prepared by freeze drying red beets and grinding them to fine powder before encapsulating in gelatine capsules. Red beets do not contain anthocyanins. |
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| Placebo Juice L1 | Dietary Supplement | Placebo juice was prepared from water, sugars, citric acid, sodium citrate, and artificial colors and flavours, then pasteurized. The placebo juice contains no anthocyanins. |
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| Blueberry Juice L1 | Dietary Supplement | Blueberry Juice L1 was commercially prepared single strength blueberry juice composed of a 50:50 blend of Rubel (Vaccinium corymbosum L.) and Tifblue (Vaccinium ashei Reade) cultivars. Colorimetric analysis showed that L1 juice contained 6.83 (SD=0.20) mg cyanidin-3-glucoside equivalents (C3GE)/g dry mass at the start of the study, declining to 5.52 (SD=0.09) mg C3GE/g dry mass after 3 months refrigerated storage. |
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| Rate of recovery of visual acquity after retinal photostress (L1). | After dark adaptation testing (primary outcome) and contrast sensitivity and visual acuity testing (other pre-specified outcome measures) participants are subjected to photostress of the retina using bright light. The time (sec) required to recover pre-stress acuity is measured. | Pre-intervention and then testing for changes after 8 and 12 weeks of intervention and 4 and 8 weeks of washout. |
| Testing preintervention and testing for changes after 3 weeks of intervention and 3 weeks of washout |
| Visual acuity and contrast sensitivity testing after dark adaptation (L1). | After dark adaptation testing (primary outcome measure) and before testing rate of recovery from photo stress (secondary outcome) visual acuity in darkness and contrast sensitivity in darkness was measured using defined optotypes with different degrees of crowding and contrast. Performance was defined as the number of correct answers in 12 tests of acuity and 8 tests of contrast sensitivity. | Testing preintervention and testing for changes after 8 & 12 weeks of intervention and 4 & 8 weeks of washout |
| D005128 |
| Eye Diseases |
| D012816 | Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D000588 |
| Amines |
| D015306 | Biogenic Monoamines |
| D001679 | Biogenic Amines |
| D002395 | Catecholamines |
| D002396 | Catechols |
| D010636 | Phenols |
| D001555 | Benzene Derivatives |
| D006841 | Hydrocarbons, Aromatic |
| D006844 | Hydrocarbons, Cyclic |
| D006838 | Hydrocarbons |