Blueberry Effects on Dark Vision and Glare Recovery

NCT01942746 | Completed

• 1 other identifier: Blueberries and Vision
• Study Type: interventional
• Target: 72
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Blindness and Low Vision

Keywords

blueberry; anthocyanin; dark vision; photo bleaching; Visual Perception; Photic Stimulation

Outcome Measures

Primary Outcomes (2)

• 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

Secondary Outcomes (2)

• Rate of recovery of visual acuity after retinal photostress (S2).

  Pre-intervention testing and testing for changes after 3 weeks of intervention and 3 weeks of washout

• Rate of recovery of visual acquity after retinal photostress (L1).

  Pre-intervention and then testing for changes after 8 and 12 weeks of intervention and 4 and 8 weeks of washout.

Other Outcomes (2)

• Visual acuity and contrast sensitivity testing after dark adaptation (S2).

  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).

  Testing preintervention and testing for changes after 8 & 12 weeks of intervention and 4 & 8 weeks of washout

Study Arms (4)

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).

Dietary Supplement: Blueberry Juice S2; Dietary Supplement: Blueberry Juice L1

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.

Dietary Supplement: Blueberry Capsules S2

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.

Dietary Supplement: Placebo Capsule S2; Dietary Supplement: Placebo Juice L1

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.

Interventions

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.

Also known as: Single-strength blueberry juice, commercially prepared

Blueberry Juice

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.

Also known as: freeze-dried blueberry juice powder

Blueberry Capsules

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.

Also known as: Red beet powder

Placebo

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.

Placebo

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.

Also known as: single strength blueberry juice, commercially prepared

Blueberry Juice

Eligibility Criteria

• Age: 35 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Atlantic Food and Horticulture Research Center: lead
• Dalhousie University: collaborator
• U.S. Highbush Blueberry Council: collaborator

Study Sites (1)

Atlantic Food and Horicultural Research Center

Kentville, Nova Scotia, B4N1J5, Canada

Location

Related Publications (1)

• 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.

  PMID: 25335781 DERIVED

MeSH Terms

Conditions

Blindness; Vision, Low

Interventions

blueberry extract; Epinephrine

Condition Hierarchy (Ancestors)

Vision Disorders; Sensation Disorders; Neurologic Manifestations; Nervous System Diseases; Eye Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Ethanolamines; Amino Alcohols; Alcohols; Organic Chemicals; Amines; Biogenic Monoamines; Biogenic Amines; Catecholamines; Catechols; Phenols; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons

Study Officials

• Wilhelmina Kalt, PhD

  Agriculture and Agri-Food Canada

  PRINCIPAL INVESTIGATOR

• Francois Tremblay, PhD

  Dalhousie University and IWK Health Center

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Scientist

Study Record Dates

• First Submitted: May 23, 2013
• First Posted: September 16, 2013
• Study Start: July 1, 2005
• Primary Completion: July 1, 2006
• Study Completion: July 1, 2006
• Last Updated: September 16, 2013

Record last verified: 2013-09

Locations

CA (1)