Most of us don’t give much thought to the humble cranberry outside of preparing for Thanksgiving or Christmas dinner — and many people never touch this lovely red berry the rest of the year! However, cranberry has a long history of American folk use as a medicinal food year-round for urinary problems, liver and gall bladder complaints, arthritis and mild constipation. Throughout the centuries, most cultures have made little distinction between medicine and food, so many medicinal herbs were built into daily dishes. Thus many of the herbs and foods we think of today as culinary are also medicinal. Cranberry’s use as an accompaniment to a robust, cholesterol-laden traditional holiday dinner of roast turkey with gravy, dressing and potatoes illustrates the simple beauty of this herbal wisdom. Cranberry’s actions perfectly meet the digestive and eliminative demands that this meal makes on our bodies.

Cholesterol accumulations in the body are first and foremost a signal that the liver is unable to keep up with the digestion of fats, and therefore cholesterol gets farmed out to other regions as a holding tank, including the circulatory system. As most of us can attest, cranberry is rich in bitter principles, elements traditional herbalists credit with stimulating the liver and fat digestion. Secondly, when digestion is insufficient — which is often the case with such Herculean dinners — partially digested foods may prematurely exit the stomach to the intestinal tract where they may ferment and cause constipation. This is where cranberry’s laxative actions may be much welcomed. Third, fat-laden foods are thought to clog the kidneys, thus slowing detoxification and making us more susceptible to infection in the urinary tract. According to traditional herbalism, we are most susceptible to this effect in the colder months of the year when the kidneys are thought to run more slowly. This is particularly noteworthy in light of our holidays arriving at the beginning of the cold months in much of North America, shortly after the wild cranberry becomes ripe.

Cranberry is a truly North American herb, naturally occurring in boggy areas of the Eastern seaboard, where they are cultivated today. Clinical research on cranberry began in the 1930s; it gained momentum in the 60s and 70s with a number of clinical studies focusing on chronic urinary infections. Today, researchers are still revealing cranberry’s numerous health effects. Clinical studies have shown that the daily administration of cranberry juice or supplements helps to reduce the severity of symptoms accompanying urinary infections, like burning urination or bladder pain, and it may reduce the number of infections if used preventively.

Early researchers thought that cranberry’s benefits for urinary complaints resulted from acidifying the urine with its own acidic constituents, thus lowering pH levels. This was attributed to hippuric acid. This theory has been abandoned due to conflicting evidence from later studies, showing that the concentration of hippuric acid in cranberry does not sufficiently acidify the urine to inhibit microbial growth. However, an early study from the 1930s showed that cranberries (not their juice) significantly lowered alkali reserves. In other words, rather than making the urine more acidic by the addition of its own acidic constituents, cranberry reduced the opposite mode, alkalinity, to create a more acidic environment.

Other later studies have confirmed that cranberry prevents bacteria from attaching to the urinary linings, where they can multiply, thus lowering bacterial levels found in urine samples. This includes activity against E. coli, which often is accidentally transferred to the urinary tract from the rectum. Cranberry also contains a lactone called parascorbic acid, which is active against fungi. This is a particularly interesting research finding, in that many people who are prone to urinary infections have chronic candida infections, or may develop secondary yeast infections on top of bacterial urinary infections. Cranberry is also reported to be high in vitamin C, another compound that helps our body fight infection. Other studies have demonstrated that cranberry may benefit chronic urethral inflammation, cystitis and kidney stones through reducing calcium crystallization. Incidentally, many holistic systems suggest that mineral crystallization in the kidneys, including that of calcium, is a mechanism in arthritis.

Cranberry belongs to the same plant genus as blueberry and bilberry, sharing many similar constituents. These include four major anthocyanins, bluish-tinged flavonoid compounds that provide antioxidant and anti-inflammatory actions plus cardiovascular protection. This may in part explain the joint and liver benefits noted by traditional herbalists, along with its bitter principles, which also stimulate peristalsis in the intestines. Antioxidant protection is especially important when the detoxifying mechanisms of the urinary tract, liver and bowels are compromised. The antioxidant actions plus some preliminary evidence that cranberry may benefit cholesterol levels are good news for heart and circulatory health as well.

Cranberry often contains significant levels of iron, depending on where and how it’s cultivated. This may explain why Native Americans from the Eastern seaboard often used cranberry as a blood tonic, along with its detoxifying actions. Many systems of herbalism employ a system of energetics to describe a plant’s actions and the characteristics of a disease or a patient’s constitution. For instance some herbs are described as cooling, others as warming, as are constitutions or conditions. In the case of iron, it is often attributed with warming properties. Certainly the well-known nutritional research on anemic women (who often have complaints of cold hands and feet as secondary symptoms) bears out the benefits of supplemental iron in this regard. Interestingly, women suffer from urinary infections more frequently than men, as well as often having sub-clinical levels of iron deficiency, and those who do often complain of being cold! Additionally, from an energetic standpoint, a plant contains a number of compounds that balance each other out energetically. This balance is thought to transfer therapeutically as well. In the case of cranberry, the presence of significant amounts of iron, which is considered warming energetically, tends to balance the bitter digestion-stimulating principles and the infection and inflammation-fighting constituents, which are considered strongly cooling.

Some recent preliminary research has suggested that cranberry’s activity against bacteria may extend to the bacteria in the mouth responsible for plaque and gum disease. Recent research has located a compound in cranberry that is undergoing testing as a possible cancer treatment. This compound occurs in a number of other plants as well, including substantial amounts in lavender, lemongrass, mints and lemon. The bioavailability of this compound ingested by humans from raw herb sources has not been yet established, much less any proof from oral administration of the whole herb of medicinal activity. It’s important to know that many, many plants are credited with benefits for cancer or tumors and other growths. A considerable amount of research will need to be undertaken to see if these are promising leads or not regarding the use of these raw herbs in this way. One of cranberry’s anthocyanins has also been reported to have benefits for cancer. Don’t forget its antioxidant activities, which may also figure into the picture here. However, all of this is a long way from saying that the naturally-occurring compounds in these plants, or those versions released in the body during digestion, have proven benefits for cancer at this time.

For the greatest purity and activity, look for a standardized cranberry product that uses no harmful solvents in the extraction process, like acetone or hexane, and is free of binders or excipients like stearic acid, dextrose or maltose. Because out-of-control urinary infections can cause serious organ damage, it is important not to self-diagnose or skip antibiotics if your physician deems them necessary. However, cranberry can be a helpful tool for relieving the secondary symptoms that can be so irritating and painful, and it may help to prevent an outbreak. Cranberry is a wonderful herbal tool to have on hand year-round, especially if you are prone to urinary complaints. Cranberry has gentle digestion and elimination — enhancing properties that we can reach for any time of year when we’ve overdone it, are feeling sluggish or have aching joints.

Selected References

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Brinker F. Vaccinium macrocarpon. Eclectic Dispensatory, vol. 2. Eclectic Medical Publications 1995.

Camire A & F Clydesdale. High pressure liquid chromatography of cranberry anthocyanins. Journal of Food Science 1979; 44.

Cardellina J & J Meinwald. Isolation of parascorbic acid from the cranberry plant, Vaccinium macrocarpon. Phytochemistry 1980; 19: 2109-2200.

Fellers C et al. Effect of cranberries on urinary acidity and blood alkali reserve. Sept. 1933.

Gibson L et al. Effectiveness of cranberry juice in preventing urinary tract infections in long-term care facility patients. Journal of Naturopathic Medicine 1991; 2(1).

Grieve M. A Modern Herbal. Dover 1931.

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McCaleb R et al. Encyclopedia of Popular Herbs. Prima Publishing 2000.

Pizzorno J & M Murray. An Encyclopedia of Natural Medicine. Prima Publishing, 1991.

Papas P et al. Cranberry juice in the treatment of urinary tract infections. Southwestern Medicine January 1966; 47(1).

Pedersen M. Nutritional Herbology: A Reference Guide to Herbs. Whitman 1994.

Schmidt D & A Sobota. An examination of the anti-adherence activity of cranberry juice on urinary and nonurinary bacterial isolates. Microbios 1988; 55: 173-181.

Sidrovhic E et al. Accumulation of iron in large cranberry plants. Khim. Selsk. Khoz. 1987; 1: 41-4.

Sobota A. Inhibition of bacterial adherence by cranberry juice: potential use for the treatment of urinary tract infections. Journal of Urology May 1984; 131.

Uphof JC. Dictionary of Economic Plants. Cramer 1968.

Werbach M & M Murray. Botanical Influences on Illness. Third Line Press 1994.

Zafiri D et al. Inhibitory activity of cranberry juice on adherence of type 1 and type P fibriated Escherichia coli to eucaryotic cells. Antimicrobial Agents and Chemotherapy January 1989; 33(1): 92-98.