General Description
The cranberry is a member of the plant family Ericaceae, which includes
a number of edible berries such as blueberries, huckleberries, and
bilberries. The plant is an evergreen, fruit-bearing vine found
in bogs and swamps throughout much of Europe, Asia, and North America.
Most commercially grown cranberries are produced in bog fields in
New England, Wisconsin, Washington, Oregon, and Eastern and Central
Canada. The primary cultivated species, Vaccinium macrocarpon, is
a woody vine that produces stems or runners which can reach lengths
of six feet or more. From these runners grow short upright branches
(about two to three inches long) which bear the flowers and fruit.
The small (7-13 mm long and 2-6 mm wide), oval-shaped leaves stay
on the plant about two years and vary in color from dark, glossy
green during summer to a dull, reddish brown during the dormant
winter months. The plant flowers from June through July, producing
small, pale-rose colored blossoms. The bitter-tasting fruit, which
are bright red in color and nearly spherical in shape, are used
widely as a food and are also used for medicinal purposes.
Health applications
History and traditional use
Cranberries have been used as a food since ancient times. As far
back as the Bronze age, an early Scandinavian form of beer was being
made from wheat, cranberries, myrtle, and honey. The early European
explorers of America found cranberries growing abundantly and noted
that the fruit was used widely by native tribes. Native Americans
used cranberries in foods such as pemmican and succotash, to make
dyes for blankets and rugs, and in poultices for wounds. Cranberries
remain popular to this day as an ingredient in beverages, sauces,
jellies, salads, and stuffings. Cranberry juice and concentrated
cranberry supplements are used in folk medicine for urinary tract
infections.
Chemical composition
Most of cranberry's activity in the body is attributed to its
concentration of proanthocyanidins, a group of antioxidant flavonoids
found in red, blue, and purple colored berries. Cranberry also
contains vitamin C and (in trace amounts) a variety of other essential
vitamins and minerals.
Urinary tract infections
Herbalists have long recommended cranberry juice for the prevention
and treatment of recurrent urinary
tract infections (UTIs), and modern clinical studies appear
to support this use. Research indicates that women who consume
cranberry juice daily can reduce their risk of UTIs by 50 percent
or more.1-3 The results of one study suggest
that cranberry juice may be more effective in treating than preventing
UTIs,3 but it appears to useful for both purposes.
The method of action by which cranberry inhibits UTIs has been
the subject of much debate. Cranberry has shown the ability to
increase the acidity of the urine,4-5 and
this action was initially thought to be responsible for the herb's
protective role against UTIs. More recent studies indicate that
cranberry inhibits the ability of bacteria cells to adhere to
the lining of the urinary tract and cause infection.6,7
Dosage/toxicity
The optimum dosage of cranberry juice for UTIs has yet to be determined.
Because many commercial cranberry drinks (cranberry juice cocktails)
contain less than 30 percent cranberry juice, and most are heavily
sweetened with sugar, many herbalists recommend using concentrated
(10:1) cranberry capsules or tablets in doses equivalent to 1,600
mg per day. Cranberry juice has no known toxicity and appears
to be very safe, with no negative side effects reported at this
dosage. Increasing intake of fluids is often recommended for people
taking cranberry supplements. Cranberry should not be used as
a substitute for antibiotics during acute urinary tract infection.
Because acute urinary tract infections can be dangerous, even
lethal, they should be diagnosed and treated by a physician. |
