Effects of blueberry and cranberry juice consumption on the plasma antioxidant capacity of healthy female volunteers.
OBJECTIVE
To assess whether consumption of 500 ml of blueberry juice or cranberry juice by healthy female subjects increased plasma phenolic content and antioxidant capacity.


METHODS
Latin square arrangement to eliminate ordering effects. After an overnight fast, nine volunteers consumed 500 ml of blueberry juice, cranberry juice or a sucrose solution (control); each volunteer participated on three occasions one week apart, consuming one of the beverages each time. Blood samples were obtained by venipuncture at intervals up to four hours after consumption of the juices. Urine samples were also obtained four hours after consuming the juice.


RESULTS
Consumption of cranberry juice resulted in a significant increase in the ability of plasma to reduce potassium nitrosodisulphonate and Fe(III)-2,4, 6-Tri(2-pyridyl)-s-triazine, these measures of antioxidant capacity attaining a maximum after 60-120 min. This corresponded to a 30% increase in vitamin C and a small but significant increase in total phenols in plasma. Consumption of blueberry juice had no such effects.


CONCLUSIONS
The increase in plasma antioxidant capacity following consumption of cranberry juice could mainly be accounted for by an increase in vitamin C rather than phenolics. This also accounted for the lack of an effect of the phenolic-rich but vitamin C-low blueberry juice.


BACKGROUND
Funded by the Scottish Executive Rural Affairs Department and the Danish Government.
Pedersen
C B
CB
Technical University of Denmark, 2800-Lyngby, Copenhagen, Denmark.
Kyle
J
J
Jenkinson
A M
AM
Gardner
P T
PT
McPhail
D B
DB
Duthie
G G
GG
D000328:Adult; D000975:Antioxidants / Q000378:metabolism*; D001205:Ascorbic Acid / Q000097:blood; D001628:Beverages; D002614:Chelating Agents / Q000737:chemistry; D005260:Female; D005290:Ferric Compounds / Q000737:chemistry; D005638:Fruit; D006801:Humans; D007700:Kinetics; D009603:Nitroso Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D010636:Phenols / Q000097:blood; D014227:Triazines / Q000737:chemistry
D000975:Antioxidants; D002614:Chelating Agents; D005290:Ferric Compounds; D009603:Nitroso Compounds; D010636:Phenols; D014227:Triazines; C001259:Fremy's salt; D001205:Ascorbic Acid; C002849:2,4,6-tripyridyl-s-triazine