Blueberry Effects on Dark Vision and Glare Recovery

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

Interventions

DIETARY_SUPPLEMENT

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.

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.

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.

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.

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.

Sponsors & Collaborators

• Dalhousie University

  collaborator OTHER

• U.S. Highbush Blueberry Council

  collaborator OTHER

• Atlantic Food and Horticulture Research Center

  lead OTHER_GOV

Principal Investigators

• Wilhelmina Kalt, PhD · Agriculture and Agri-Food Canada

• Francois Tremblay, PhD · Dalhousie University and IWK Health Center

Study Design

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Model

CROSSOVER

Eligibility

Min Age

35 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2005-07-31

Primary Completion

2006-07-31

Completion

2006-07-31

Countries

• Canada

Study Locations