Blueberry Effects on Dark Vision and Glare Recovery

NCT ID: NCT01942746

Last Updated: 2013-09-16

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

72 participants

Study Classification

INTERVENTIONAL

Study Start Date

2005-07-31

Study Completion Date

2006-07-31

Brief Summary

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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.

Detailed Description

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Vision Tests: 1. Dark adaptometry, 2. scotopic visual acuity, 3. scotopic contrast sensitivity, 4. rod/cone conversion, 5. recovery after retinal photobleaching

Conditions

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Blindness and Low Vision

Keywords

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blueberry anthocyanin dark vision photo bleaching Visual Perception Photic Stimulation

Study Design

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Allocation Method

NON_RANDOMIZED

Intervention Model

CROSSOVER

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

DOUBLE

Participants Outcome Assessors

Study Groups

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Blueberry Juice

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).

Group Type ACTIVE_COMPARATOR

Blueberry Juice S2

Intervention Type 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.

Blueberry Juice L1

Intervention Type 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.

Blueberry Capsules

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.

Group Type ACTIVE_COMPARATOR

Blueberry Capsules S2

Intervention Type 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.

Placebo

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.

Group Type PLACEBO_COMPARATOR

Placebo Capsule S2

Intervention Type 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.

Placebo Juice L1

Intervention Type 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.

Washout (S2 and L1)

Washout periods involved no study products. Washout was 3 weeks in S2 and or 8 weeks (L1) in duration.

Group Type NO_INTERVENTION

No interventions assigned to this group

Interventions

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Blueberry Juice S2

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.

Intervention Type DIETARY_SUPPLEMENT

Blueberry Capsules S2

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.

Intervention Type DIETARY_SUPPLEMENT

Placebo Capsule S2

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.

Intervention Type DIETARY_SUPPLEMENT

Placebo Juice L1

Placebo juice was prepared from water, sugars, citric acid, sodium citrate, and artificial colors and flavours, then pasteurized. The placebo juice contains no anthocyanins.

Intervention Type DIETARY_SUPPLEMENT

Blueberry Juice L1

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.

Intervention Type DIETARY_SUPPLEMENT

Other Intervention Names

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Single-strength blueberry juice, commercially prepared freeze-dried blueberry juice powder Red beet powder single strength blueberry juice, commercially prepared

Eligibility Criteria

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Inclusion Criteria

* visual acuity better than 6/7.5 on EDTRS acuity chart at 2.5m
* visual contrast sensitivity within normal range at 2.5m as tested on Visteck 3000
* stereo acuity better than 80 seconds of arc on Frisby stereoacuity test
* no ocular history other than refractive glasses
* no family history of eye disease

Exclusion Criteria

* family history of retinal degeneration, glaucoma, diabetes, hypertension, cataract, or amblyopia (dimness in vision).
* evidence in subject (upon examination) of amblyopia (dimness in vision), manifest strabismus (unable to focus both eyes on one spot), or anisotropia (non-uniform responsiveness between both eyes).
* intraocular pressure above 21mmHG from an average of three measures using Mentor tonopen-XL
Minimum Eligible Age

35 Years

Maximum Eligible Age

65 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Dalhousie University

OTHER

Sponsor Role collaborator

U.S. Highbush Blueberry Council

OTHER

Sponsor Role collaborator

Atlantic Food and Horticulture Research Center

OTHER_GOV

Sponsor Role lead

Responsible Party

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Wilhelmina Kalt

Scientist

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Wilhelmina Kalt, PhD

Role: PRINCIPAL_INVESTIGATOR

Agriculture and Agri-Food Canada

Francois Tremblay, PhD

Role: PRINCIPAL_INVESTIGATOR

Dalhousie University and IWK Health Center

Locations

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Atlantic Food and Horicultural Research Center

Kentville, Nova Scotia, Canada

Site Status

Countries

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Canada

References

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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.

Reference Type DERIVED
PMID: 25335781 (View on PubMed)

Other Identifiers

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Blueberries and Vision

Identifier Type: -

Identifier Source: org_study_id