The New Complete Book of Food
Jersey) identified specific tannins in cranberries as the effective agents. In 2004, research-
ers at Beth Israel Medical Center (New York) published a review of 19 recent studies of
cranberries. The report, in the journal American Family Physician, suggested that a regimen
of eight ounces of unsweetened cranberry juice or one 300–400 mg cranberry extract tablet
twice a day for up to 12 months safely reduced the risk of urinary tract infections. In 2008,
a similar review by scientists at the University of Stirling (Scotland) of 10 studies showed
similar results.Adverse Effects Associated with This Food
Increased risk of kidney stones. Long-term use of cranberry products may increase the risk of
stone formation among patients known to form oxalate stones (stones composed of calcium
and/or other minerals).Food/Drug Interactions
Anticoagulants Anticoagulants (blood thinners) are drugs used to prevent blood clots. They
are most commonly prescribed for patients with atrial fibrillation, an irregular heartbeat that
allows blood to pool in the heart and possibly clot before being pumped out into the body. In
2006 researchers at the College of Pharmacy and the Antithrombosis Center at the Univer-
sity of Illinois (Chicago) reported that consuming cranberry juice while using the anticoagu-
lant warafin (Coumadin) might cause fluctuations in blood levels of the anticoagulant, thus
reducing the drug’s ability to prevent blood clots.