While they're fresh, preserve their health benefits
5 Great Recipes with Cranberries
• Cranberry Cubes
• Low-Sugar Cranberry Drinks
• Cranberry-Pear Butter
• Acorn Squash Stuffed with Cranberry Wild Rice
• Cranberry Bran Loaf
• Preparing cranberries
With fresh cranberries just coming to market, now’s the time to stock up. Preserving the tangy taste means a year’s protection against urinary troubles, dental plaque, and maybe even cholesterol and cancer.
Nearly 50 percent of all women have had a urinary tract infection (UTI) at some point in their lives. And for those who have had one, they’re more likely to have another.
Long a folk remedy for UTIs, cranberries have moved into the medical mainstream. During the past two decades, numerous articles have verified not only their ability to cure and/or prevent UTIs but have also suggested that compounds found in cranberries may inhibit tumors, dental caries, and the oxidation of LDL cholesterol.
Although antibiotics and other aggressive forms of intervention may be required to cure UTIs, cranberries can be the first line of defense to prevent their occurrence, and may be sufficient treatment to eliminate some established infections.
How cranberries work
How do cranberries—and cranberry products—act? Probably in several ways. Initially, scientists believed that cranberries’ effect derived from their ability to acidify urine, creating a less hospitable environment for bacterial growth. Recent research suggests a different mechanism: Cranberries interfere with the activity of specific strains of Escherichia coli, the bacteria associated with UTIs. Typically only those E. coli strains isolated from the urine of UTI patients are affected by cranberries.
Scientists believe that UTIs are caused, in part, by E. coli attaching to cells that line the urinary tract (the kidneys, ureters, bladder, and urethra). Although this process is still poorly understood, it probably involves interactions between specific cellular receptors and fimbriae, or tiny filaments on the UTI-causing bacteria. At least two classes of fimbriae exist, and each prefers to bind to a different type of receptor on the cell surface. Cranberry compounds may interrupt this binding process in several ways. A recent study showed that E. coli cells treated with cranberry concentrate didn’t form fimbriae.
Scientists are just beginning to identify the molecules in cranberries that inhibit UTI. One study suggests that condensed tannins, called proanthocyanadins, prevent the infections. Test-tube studies suggest that other compounds may possess similar activity. In other laboratory experiments, fructose, a natural sugar found in cranberries and most fruits, was found to inhibit one type of UTI-producing E. coli. Whether this is relevant to lower urinary tract infections is questionable, since kidneys— upstream from that area—presumably remove the sugar from urine.
Cranberry vs. the three Cs: Cavities, Cholesterol, and Cancer
A recent study suggests that cranberry also has the potential to reduce dental plaque. Plaque is composed of a raft of different bacteria, loosely bonded—or coaggregated—together. Test-tube experiments with a compound isolated from cranberries demonstrated that the compound could inhibit 58 percent of the oral bacteria strains on which it was tested. Obviously, commercial cranberry juice, with its hefty sugar content, is hardly a mouthwash candidate. However, the finding does suggest that once the compounds are isolated, they may be used as cavity fighters. It also speaks to concocting your own, lightly sugared cranberry products.
One further in-vitro study sponsored by Ocean Spray Cranberries showed that cranberry juice may inhibit oxidation of LDL cholesterol. Because cholesterol oxidation is implicated in cardiovascular disease, regular cranberry consumption may offer some protection against this condition. The study’s authors credit cranberries’ high concentration of gallic acid (a tannin-like compound) with the effects.
Cranberries may also possess at least two molecules that inhibit cancer. When whole cranberries were extracted with a variety of solvents, in-vitro studies showed some compounds inhibited the induction of an enzyme (ornithine decarboxylase) involved in the promotion of tumors. Other compounds upped the production of a second enzyme (quinone reductase) involved in detoxifying some carcinogens. What physiological significance this carries, considering the quantity of cranberries the average American consumes, is an open question.
Ahuja, S., et al. “Loss of fimbrial adhesion with the addition of Vaccinum macrocarpon to the growth medium of P-fimbriated Escherichia coli.” Journal of Urology 1998, 159:559–562.
Bomser, J., et al. “In vitro anticancer activity of fruit extracts from Vaccinium species.” Planta Medica 1996, 62:212–216.
Fleet, J. C. “New support for a folk remedy: Cranberry juice reduces bacteriuria and pyuria in elderly women.” Nutrition Reviews 1994, 52:168–170.
Sobota, A. E. “Inhibition of bacterial adherence by cranberry juice: Potential use for the treatment of urinary tract infections.” Journal of Urology 1984, 131:1013–1016.
Weiss, E. I., et al. “Inhibiting interspecies coaggregation of plaque bacteria with a cranberry juice constituent.” Journal of the American Dental Association 1998, 129:1719–1723.
Wilson, T., et al. “Cranberry extract inhibits low density lipoprotein oxidation.” Life Sciences 1998, 62: PL381–386.
Zafriri, D., et al. “Inhibitory activity of cranberry juice on adherence of type 1 and type P fimbriated Escherichia coli to eucaryotic cells.” Antimicrobial Agents and Chemotherapy 1989, 33:92–98.
Sit in on dozens of practical workshops from the leading authorities on natural health, organic gardening, real food and more!LEARN MORE