Early American physicians successfully applied crushed cranberries to tumors and wounds. They also used cranberries as a remedy for the age-old malady known as scurvy, a disease caused by a lack of vitamin C. It wasn’t too surprising, therefore, when modern scientists discovered that cranberries contain plentiful stores of this common antioxidant vitamin.
In June 2001, Finnish doctors reported much more promising evidence of the benefits of cranberry juice in preventing recurrent urinary infections in women. In a study of 150 women with urinary tract infection caused by E.coli, drinking 50ml of a cranberry-lingo berry juice concentrate every day for six months was associated with a significant reduction in recurrences.
More recent studies have suggested that cranberry juice’s alleged effectiveness against bacteria is not in its ability to acidify the urine, but in its ability to prevent bacteria from sticking to the lining of the urinary tract where they can multiply and cause infection. Two anti-adhesion factors have been isolated from cranberry juice, fructose and another polymeric compound of unknown nature. Several fruit juices have been tested, but only
cranberry and blueberry juice contains the latter inhibitor.
Benefits of cranberry juice
Early work focused on the potential of the cranberry for urine acidification, with resulting bacteriostasis. The mode of action of cranberry juice is associated with interference with the adherence of a particular surface component of E. Coli and other gram-negative bacteria, to at least a few types of epithelial cells. Cranberry juice fructose and an uncharacterized high molecular weight polymeric compound are responsible for the inhibition of adhesion activity.
A new study finds that the juice can lower the risk of heart disease for people with high cholesterol, and provide antioxidant benefits. Three glasses per day raised good cholesterol 10%, which in turn decreased their risk of heart disease by 40%. The antioxidant benefits were noticeable with just one or two glasses a day. Scientists are discovering that cranberry juice may also be good for the heart. According to recent clinical results conducted at the University of Laval in Quebec City, Quebec, a daily serving of low calorie cranberry cocktail may improve circulation by increasing the level of HDL (good cholesterol) by 8 percent on average, and by acting as a powerful antioxidant.
Cranberries contain hippuric acid, which has antibacterial effects on the body, as well as natural antibiotic ingredients. Cranberries also contain plant pigments called bioflavanoids, which help, repair damaged molecules formed when the body uses up oxygen. Research in Europe has shown that anthocynin, one of these bioflavanoids, aids the formation of visual purple, a pigment in the eyes instrumental in color and night vision.
The ‘anti-stick’ power of cranberry against the bacteria causing urinary tract infections is well known, and this same mechanism also shows promise against the various bacteria responsible for stomach ulcers and gum disease. The accumulating science regarding heart health benefits further raises cranberry’s profile among healthful foods and beverages.
“There is no evidence that drinking or eating cranberry products can cure a UTI once the bacteria have established infection,” said Kalpana Gupta, MD, principal investigator of the University of Washington study. “The next step is to evaluate our findings in a larger group of women, and then conduct a trial to help determine if the laboratory findings translate into clinical differences in the rate of UTI depending on the dosage of cranberry consumed.”
The acidity of cranberry juice assists the digestion of high fat content foods and works to increase the appetite.
Symptoms of high intake
In any case, it seems clear that for an otherwise healthy individual, drinking moderate amounts of cranberry juice can’t do any harm and might even do some good.
Cranberry juice has a moderately high concentration of oxalate, a common component of kidney stones, and should be limited in persons with a history of nephrolithiasis.
A patient suspecting a urinary tract or kidney problem, he must consult a physician.
Recommended dosage of cranberry juice (not cocktail) as a preventative of urinary tract infections (UTIs), is 12 to 32 fluid ounces (360 to 960 ml).
In the Finnish study, 50ml/day of juice concentrate seemed to provide a beneficial effect while in the earlier US study in elderly women, it was 300ml/day, which seemed to reduce the bacterial content of the urine