Cranberry

Vaccinium macrocarpon

Cranberry Parts used Uses Habitat and cultivation Constituents How much to take Side effects and cautions

The cranberry is an evergreen shrub with long runners and vines. The flowers, which appear in the spring, are light pink to purple. By summer they fall away and leave brilliant red berries. Leaves are tiny and narrow, lining the vines evenly.

The American cranberry, also known as the trailing swamp cranberry, is referred to scientifically as Vaccinium macrocarpon Ait. (family Ericaceae). Many varieties of the species are cultivated extensively in natural or artificial bogs throughout the United States, but especially in Massachusetts and Washington. Cranberry fruits have long been valued for their pleasant acidulous flavor and have become a mainstay in sauces, relishes, and jellies that are especially favored at Thanksgiving time.

In 1923, American scientists showed that the urine of test subjects became more acid after eating large amounts of cranberries. Because bacteria favor an alkaline medium for growth, these investigators speculated that a diet which included cranberries might be helpful in preventing and treating recurrent urinary tract infections (UTI). This condition is especially prevalent among women and often causes considerable discomfort. Until the advent of the sulfa medications and the antibiotics, conventional medical treatment was largely ineffective.

Interested in any potential cure, women suffering from UTI began to consume quantities of the commercially available cranberry juice cocktail and reported, anecdotally, very satisfactory results. Recommendations of the treatment spread, not only by word of mouth, but in occasional articles in regional medical journals. One of the latter reported symptomatic relief from chronic kidney inflammation in female patients who drank 6 ounces of cranberry juice twice daily. However, in 1967, a study showed that consumption of the commercial cranberry juice cocktail did not acidify the urine sufficiently to produce an appreciable antibacterial effect. Such negative findings did not appear to influence adversely consumption of the product by UTI sufferers who remained convinced of its effectiveness.

Subsequent studies have provided evidence that the effectiveness of cranberry juice is not due to its ability to acidify the urine but to an entirely different mechanism. It appears to inhibit the ability of the microorganisms to adhere to the epithelial cells that line the urinary tract, thus rendering the environment there less suitable for the growth of the bacteria that typically cause UTI. The most common of these bacteria, Escherichia coli, produces two constituents known as adhesins that cause the organism to cling to the cells where they multiply rapidly. This adhering ability is inhibited by two constituents of cranberry juice. One of the anti-adhesin factors is fructose; the other is a polymeric compound of unknown nature. Of a number of fruit juices tested, only cranberry and blueberry (both species of the same genus, Vaccinium) contained this latter, high-molecular-weight inhibitor. In addition to these anti-adhesin factors, cranberries contain various carbohydrates and fiber, as well as a number of plant acids, including benzoic, citric, malic, and quinic.

Many persons consume 3 or more fluidounces daily of the cocktail (one-third of which is pure juice) as a preventive or 12 to 32 fluidounces daily as a treatment for UTI. Alternatively, capsules containing dried cranberry powder are now available, 6 capsules being equivalent to 3 fluidounces of cranberry juice cocktail. These contain more fiber and much less sugar than the cocktail, but an artificially sweetened cocktail is now available. It is also theoretically possible to consume either fresh or frozen cranberries: about 1.5 ounces equals 3 fluidounces of cocktail. However, in practice this is not feasible because of their high acidity and extremely sour taste. An appropriate cranberry product does seem to be a useful adjunct in the prevention and treatment of urinary tract infections.

PARTS USED

Berry.

USES

The Pilgrims in America supposedly feasted on cranberry dishes at their first Thanksgiving in 1621. Such dishes became a national tradition, however, only after General Ulysses S. Grant ordered them served to Union troops during the Civil War. Native Americans used cranberries as a source of dye. Cranberry juice cocktail is available commercially. Because pure cranberry juice is too acidic and sour to drink, water and sugar are added.

German researchers in the 1840s discovered that people who have eaten cranberries pass urine with hippuric acid, a bacteria-fighting chemical. Recent studies support the speculation that eating cranberries or drinking their juice can prevent or fight urinary tract infections. Hippuric acid prevents Escherichia coli (E. coli) from adhering to the urinary tract. Cranberries also contain arbutin, which fights yeast infections. The berries are also used as a "urinary deodorant:' Native Americans are known to have treated wounds with poultices of cranberries. The Pilgrims who used these berries to treat fevers were not misguided; the berries have a high vitamin C content.

HABITAT AND CULTIVATION

The cranberry is native to North America. For best growth cranberry requires boggy soil.

CONSTITUENTS

Proanthocyanidins; fructose; flavonol glycosides, including leptosine; catechin; triterpenoids; organic acids, including citric, malic, benzoic, quinic and hippuric acids; miscellaneous compounds, including vitamin C and an unidentified large-molecular-weight molecule.

HOW MUCH TO TAKE

People often take one capsule or tablet of a concentrated cranberry juice extract two to four times per day. Several glasses (16 ounces total) of a high-quality cranberry juice (not the cocktail) each day can approximate the effect of the cranberry concentrate.

SIDE EFFECTS AND CAUTIONS

There are no known side effects with cranberry concentrate, and it is safe for use during pregnancy and lactation. Cranberry should not be used as a substitute for antibiotics during an acute urinary tract infection.